Yasuro Atoji

Publications of Yasuro Atoji

• Differences in extrinsic innervation patterns of the small intestine in the cattle and sheep.

  Authors: Yasushige Ohmori, Yasuro Atoji, Shouichiro Saito, Hiroshi Ueno, Yasuo Inoshima, Naotaka Ishiguro

  Autonomic neuroscience : basic & clinical. 12/2011; 167(1-2):39-44.

  After oral challenge of the pathological prion protein, the pathogen was first detected in the distal ileum and then deposited in the brain. The present study aims determining the possible neuronalAfter oral challenge of the pathological prion protein, the pathogen was first detected in the distal ileum and then deposited in the brain. The present study aims determining the possible neuronal transport pathways from the small intestine to the brain in the cattle and sheep using a tracer protein. After horseradish peroxidase was injected into the wall in the duodenum of the calf and lamb and in the ileum of the lamb, the greater part of labeled neurons was detected in the celiac and cranial mesenteric ganglion complex. In the dorsal root ganglia T3 to L4 of both animals, some sensory neurons were always found to be labeled. Some parasympathetic preganglionic neurons were labeled in the dorsal motor nucleus of the vagus nerve after injections into the duodenum of the cattle and sheep, but extremely a small number of them were labeled after ileal application. The number of labeled sensory neurons in the nodose ganglion after duodenal injections of the sheep was much greater than that after duodenal application of the cattle. After ileal injections in the sheep, practically no labeled sensory neurons were found in the nodose ganglion. These results suggest that the pathological prion protein is mainly transported to the spinal cord and brain via the sympathetic nervous system and partially via the sensory neurons in the dorsal root ganglia. The vagus nerve seems to contribute to the transport of the pathogen not from the ileum, but from the duodenum.

• Afferent and efferent projections of the mesopallium in the pigeon (Columba livia).

  Authors: Yasuro Atoji, J Martin Wild

  The Journal of comparative neurology. 09/2011; 520(4):717-41.

  The mesopallium is a thick cell plate occupying a substantial portion of the avian dorsal pallium, but its hodology is incompletely known. In pigeons we examined fiber connections of the frontodorsalThe mesopallium is a thick cell plate occupying a substantial portion of the avian dorsal pallium, but its hodology is incompletely known. In pigeons we examined fiber connections of the frontodorsal (MFD) and frontoventral mesopallium (MFV), the ventrolateral mesopallium (MVL), the lateral (MIVl) and medial (MIVm) parts of the intermediate ventral mesopallium, and the caudal mesopallium (MC). MFV, MIVl, and MC connect reciprocally with secondary centers of the trigeminal, tectofugal, and auditory systems, respectively. MVL forms reciprocal connections with both the entopallial core and belt. MFV, MIVl, MVL, and MC receive thalamic inputs different from those of primary sensory pallial regions and have reciprocal connections with the caudolateral nidopallium (NCL) or arcopallium. MIVm has a strong reciprocal connection with the intermediate medial nidopallium. It receives afferents from the visual Wulst, rostral MC, posterior dorsointermediate thalamic nucleus, and caudal part of the posterior dorsolateral thalamic nucleus, is connected reciprocally with the arcopallium, and projects to NCL. MFD has reciprocal connections with the medial frontal nidopallium, arcopallium, posterior pallial amygdala, dorsolateral corticoid area, and projects to the medial part of medial striatum and hypothalamus. These results indicate that six subdivisions of the mesopallium have strong connections with corresponding portions of the nidopallium. In particular, the sensory mesopallial components of MFV, MIVl, MVL, and MC form parallel pathways to the one-way sensory streams in the nidopallium and make either feedback or feedforward circuits to the secondary centers of the nidopallium.

• Immunohistochemical localization of vesicular glutamate transporter 2 (vGluT2) in the central nervous system of the pigeon (Columba livia).

  Authors: Yasuro Atoji

  The Journal of comparative neurology. 05/2011; 519(14):2887-905.

  Glutamatergic neurons are distributed widely in the telencephalic pallium of birds, but their targets are unknown. In the present study, a polyclonal antibody was produced against pigeon vesicularGlutamatergic neurons are distributed widely in the telencephalic pallium of birds, but their targets are unknown. In the present study, a polyclonal antibody was produced against pigeon vesicular glutamate transporter 2 (vGluT2) and was used for Western blot and immunohistochemistry to detect projection targets of glutamatergic neurons in the pigeon central nervous system. The molecular weight of vGluT2 was measured at 65 kDa. vGluT2 immunoreactivity was observed in neuropil, but not in neuronal cell bodies or glia. Immunoreactive neuropil generally appeared homogeneous, but fine granules or puncta were found in many areas or nuclei. The telencephalon showed strong immunoreactivity, except for the globus pallidus. In particular, the mesopallium and hippocampal formation revealed the most intense immunostaining. In the diencephalon, vGluT2 immunoreactivity was intense in the dorsal thalamus and hypothalamus. In the midbrain, strong immunostaining was seen in the periaqueductal gray, the dorsal part of the lateral mesencephalic nucleus, and the isthmo-optic nucleus. The optic tectum showed moderate immunoreactivity. In the cerebellar cortex, glomeruli in the granular layer were intensely immunoreactive, and the molecular layer showed intensely homogeneous immunostaining. In the caudal brainstem, the cochlear magnocellular and angular nuclei showed strongly immunoreactive puncta around neuronal cell bodies. In the spinal cord, the dorsal horn revealed moderate immunoreactivity and the marginal nucleus was strongly immunoreactive. Ultrastructural observations revealed that vGluT2 immunoreactivity is localized in asymmetric, presynaptic terminals. The present results indicate an extensive distribution of glutamatergic projections and circuits in the avian central nervous system.

• Amino acid substitutions at positions 242, 255 and 268 in rabies virus glycoprotein affect spread of viral infection.

  Authors: Yuki Ito, Naoto Ito, Shouichiro Saito, Tatsunori Masatani, Keisuke Nakagawa, Yasuro Atoji, Makoto Sugiyama

  Microbiology and immunology. 02/2010; 54(2):89-97.

  Rabies virus Nishigahara strain kills adult mice after intracerebral inoculation, whereas the derivative RC-HL strain does not. It has previously been reported by us that the R(G 242/255/268) strain,Rabies virus Nishigahara strain kills adult mice after intracerebral inoculation, whereas the derivative RC-HL strain does not. It has previously been reported by us that the R(G 242/255/268) strain, in which amino acids at positions 242, 255 and 268 on the G protein have been replaced by those from the Nishigahara strain in the genetic background of the RC-HL strain, kills adult mice. This indicates that these three amino acids of G protein are important for pathogenicity of the Nishigahara strain. In order to obtain insights into the mechanism by which these amino acids affect pathogenicity, in this study spread of viral infection and apoptosis-inducing ability of the attenuated RC-HL strain and the virulent R(G 242/255/268) strain were compared. RC-HL infection spread less efficiently in the mouse brain than did R(G 242/255/268) infection. However, the apoptosis-inducing abilities of both viruses were almost identical, as shown by both in vitro and in vivo experiments. It was demonstrated that cell-to-cell spread of RC-HL strain was less efficient than that of R(G 242/255/268) strain in mouse neuroblastoma cells. These results indicate that the three amino acid substitutions affect efficiency of cell-to-cell spread but not apoptosis-inducing ability, probably resulting in the distinct distributions of RC-HL and R(G 242/255/268) strain-infected cells in the mouse brain and, consequently, the different pathogenicities of these strains.

• Afferent and efferent projections of the central caudal nidopallium in the pigeon (Columba livia).

  Authors: Yasuro Atoji, J Martin Wild

  The Journal of comparative neurology. 11/2009; 517(3):350-70.

  The central caudal nidopallium (NCC) is a large subdivision of the nidopallium in the pigeon brain, but its connectional anatomy is unknown. Here, we examined the connections of NCC by usingThe central caudal nidopallium (NCC) is a large subdivision of the nidopallium in the pigeon brain, but its connectional anatomy is unknown. Here, we examined the connections of NCC by using tract-tracing methods. Injections of cholera toxin B-chain (CTB) in NCC labeled many neurons within NCC. Outside NCC, many labeled neurons were found in the dorsal intermediate mesopallium and medialmost part of the medial intermediate nidopallium, with a few in the intermediate (AI) and medial (AM) arcopallium. In the thalamus, labeled neurons were located in the subrotundal nucleus, the shell region of nucleus ovoidalis, and the caudal part of the dorsolateral posterior thalamic nucleus. Injections of biotinylated dextran amine (BDA) in NCC labeled many fibers running rostrocaudally within NCC. Some of these terminated in the dorsal intermediate mesopallium, but the size of the terminal field was smaller than the region of the dorsal intermediate mesopallium that provided the projection to NCC. NCC sent numerous efferents to AI and AM but few to the thalamus. In contrast, after CTB injections in the dorsal intermediate mesopallium, a few neurons were labeled in NCC, but, after BDA injections in the dorsal intermediate mesopallium, large numbers of labeled fibers were seen to project widely throughout NCC. These findings indicate that the flow of information is predominantly from the dorsal intermediate mesopallium to NCC and from there to the arcopallium (AI and AM). The arcopallial outflow to the medial hypothalamus could imply that NCC is involved in neuroendocrine and autonomic functions and is limbic in nature.

• Immune cell types involved in early uptake and transport of recombinant mouse prion protein in Peyer's patches of calves.

  Authors: Sein Lwin, Yasuo Inoshima, Yasuro Atoji, Hiroshi Ueno, Naotaka Ishiguro

  Cell and tissue research. 10/2009;

  We have previously reported the early uptake and transport of foreign particles into Peyer's patches (PPs) of newborn and 2-month-old calves and shown that the peak uptake of particles occurs 6 hWe have previously reported the early uptake and transport of foreign particles into Peyer's patches (PPs) of newborn and 2-month-old calves and shown that the peak uptake of particles occurs 6 h after inoculation, in addition to site- and size-related effects on particle uptake. We now report the distribution of immune cells within PPs of the distal ileum in newborn and 2-month-old calves inoculated with carbon black. The types of immune cells involved in the early uptake and transport of recombinant mouse prion protein (rMPrP) within PPs of newborn calf were investigated by using monoclonal antibodies CD11c, CD14, CD68, CD172a, and CD21. CD11c(+), CD14(+), CD68(+), CD172a(+), and CD21(+) immune cells were widely distributed in four tissue compartments (villi, dome, interfollicular region, and follicles) of PPs in the distal ileum of newborn and 2-month-old calves, whereas CD11c(+), CD14(+), CD172a(+), and CD21(+) immune cells were more prominently distributed in the dome areas of newborn calves than in 2-month-old calves. Moreover, CD11c(+) and CD14(+) dendritic cells, CD172a(+) and CD68(+) macrophages, and CD21(+) follicular dendritic cells containing rMPrP were primarily observed in the dome and inner follicular regions. The deposition of rMPrP within CD11c(+), CD14(+), CD172a(+), and CD68(+) cells, but not CD21(+) cells, was detected in villous regions. rMPrP-positive immune cells within the interfollicular regions included only CD11c(+) and CD172(+) cells. Although the particles used in this investigation do not include the infectious prion protein, PrP(Sc), our experimental setup provides a useful model for studying immune cells involved in the early uptake and transport of PrP(Sc).

• Distribution of the cellular prion protein in the central nervous system of the chicken.

  Authors: Yasuro Atoji, Naotaka Ishiguro

  Journal of chemical neuroanatomy. 09/2009;

  The cellular prion protein (PrP), a cell membrane-bound glycoprotein mainly located in the dendrites and axons of the central nervous system (CNS), is responsible for transmissible spongiformThe cellular prion protein (PrP), a cell membrane-bound glycoprotein mainly located in the dendrites and axons of the central nervous system (CNS), is responsible for transmissible spongiform encephalopathies in mammals. PrP genes are widely conserved in vertebrates. In birds, the presence of PrP mRNA has been confirmed in neurons of the chicken brain, but localization of the protein remains to be determined. In the present study, we demonstrated the regional distribution of PrP in the CNS of adult chickens by immunohistochemical staining with a monoclonal antibody that recognizes chicken PrP 161-164. Immunoreactivity was observed in the neuropil, but not in neuronal somata or glial cells. It was preferentially intense in the olfactory bulb, the dorsal thalamus, the hypothalamus, and most regions of the telencephalon. Immunostaining became less intense toward the brainstem, but many nuclei were immunoreactive. Among brainstem nuclei, moderate immunostaining was observed in the nucleus of the solitary tract, dorsal motor nucleus of the vagus nerve, and substantia gelatinosa Rolandi. The cerebellar cortex was devoid of PrP immunoreactivity. The dorsal horn in the spinal cord was strongly immunoreactive. In situ hybridization with two probes of the C-terminal portion demonstrated localization of PrP mRNA in neurons of the brain and spinal cord. These findings suggest that PrP in the chicken CNS is localized in the dendrites and axons of neurons and that it is associated with certain sensory systems.

• Distribution of glutamate transporter 1 mRNA in the central nervous system of the pigeon (Columba livia).

  Authors: Yasuro Atoji, Mohammad Rafiqul Islam

  Journal of chemical neuroanatomy. 08/2009; 37(4):234-44.

  Glutamate transporter 1 (GLT1) in glial cells removes glutamate that diffuses from the synaptic cleft into the extracellular space. Previously, we have shown the distribution of glutamatergic neuronsGlutamate transporter 1 (GLT1) in glial cells removes glutamate that diffuses from the synaptic cleft into the extracellular space. Previously, we have shown the distribution of glutamatergic neurons in the central nervous system (CNS) of the pigeon. In the present study, we identified cDNA sequence of the pigeon GLT1, and mapped the distribution of the mRNA-expressing cells in CNS to examine whether GLT1 is associated with glutamatergic terminal areas. The cDNA sequence of the pigeon GLT1 consisted of 1889bp nucleotides and the amino acids showed 97% and 87% identity to the chicken and human GLT1, respectively. In situ hybridization autoradiograms revealed GLT1 mRNA expression in glial cells and produced regional differences of GLT1 mRNA distribution in CNS. GLT1 mRNA was expressed preferentially in the pallium than the subpallium. Moderate expression was seen in the hyperpallium, Field L, mesopallium, and hippocampal formation. In the thalamus, moderate expression was found in the ovoidal nucleus, rotundal nucleus, triangular nucleus, and lateral spiriform nucleus, while the dorsal thalamic nuclei were weak. In the brainstem, the isthmic nuclei, optic tectum, vestibular nuclei, and cochlear nuclei expressed moderately, but the cerebellar cortex showed strong expression. Bergmann glial cells expressed GLT1 mRNA very strongly. The results indicate that cDNA sequence of the pigeon GLT1 is comparable with that of the mammalian GLT1, and a large number of GLT1 mRNA-expressing areas correspond with areas where AMPA-type glutamate receptors are located. Avian GLT1 in glial cells probably maintain microenvironment of glutamate concentration around synapses as in mammalian GLT1.

• Distribution of vesicular glutamate transporter 2 and glutamate receptor 1 and 2 mRNA in the pigeon retina.

  Authors: Mohammad Rafiqul Islam, Yasuro Atoji

  Experimental eye research. 07/2009;

  Glutamate is an excitatory neurotransmitter in the central and peripheral nervous systems of the vertebrate. The previous studies show the presence of mRNAs of AMPA-type glutamate receptors, GluR1Glutamate is an excitatory neurotransmitter in the central and peripheral nervous systems of the vertebrate. The previous studies show the presence of mRNAs of AMPA-type glutamate receptors, GluR1 and GluR2, in the optic tectum of the pigeon, suggesting glutamatergic input from the retina. The present study examined localization of vesicular glutamate transporter 2 (VGLUT2) and GluR1 and GluR2 to confirm source of glutamatergic neurons in the pigeon retina by in situ hybridization histochemistry. VGLUT2 mRNA expressed in the inner nuclear layer and ganglion cells, while GluR1 and GluR2 mRNAs were observed in the inner nuclear layer, ganglion cells, and superficial layers of the optic tectum. The results suggest that photoreceptor cells, bipolar cells and ganglion cells are glutamatergic in the avian retina as in mammals.

• Localization of sympathetic, parasympathetic and sensory neurons innervating the distal ileum of the cattle.

  Authors: Yasushige Ohmori, Yasuro Atoji, Shouichiro Saito, Hiroshi Ueno, Yasuo Inoshima, Naotaka Ishiguro

  The Journal of veterinary medical science / the Japanese Society of Veterinary Science. 01/2009; 70(12):1289-94.

  After oral challenge of the pathological prion protein, the causative agent of bovine spongiform encephalopathy, the pathogen was first detected in the distal ileum and then deposited in the brain.After oral challenge of the pathological prion protein, the causative agent of bovine spongiform encephalopathy, the pathogen was first detected in the distal ileum and then deposited in the brain. The present study aims determining the possible neuronal transporting pathways from the ileum to the brain in the cattle using a tracer protein. After horseradish peroxidase was injected into the wall of the distal ileum in the calf, almost all labeled neurons were detected in the celiac and cranial mesenteric ganglion complex. Only a few labeled neurons existed in the caudal mesenteric ganglion and the paravertebral ganglia. They were sympathetic postganglionic neurons. In the dorsal root ganglia T5 to L4, some sensory neurons were found to be labeled. Only a small number of parasympathetic preganglionic neurons were labeled in the dorsal motor nucleus of the vagus nerve. No labeled sensory neurons were found in the nodose ganglion. These results suggest that the pathological prion protein is mainly transported to the spinal cord and brain via the sympathetic nervous system and partially via the sensory neurons in the dorsal root ganglia. The vagus nerve does not seem to contribute to the transport of the pathogen from the ileum directly.

• Distribution of vesicular glutamate transporter 2 and glutamate receptor 1 mRNA in the central nervous system of the pigeon (Columba livia).

  Authors: Mohammad Rafiqul Islam, Yasuro Atoji

  The Journal of comparative neurology. 11/2008; 511(5):658-677.

  Glutamate acts as the excitatory neurotransmitter in the central nervous system (CNS) and is mediated largely by the vesicular glutamate transporters (VGLUT1-3) andGlutamate acts as the excitatory neurotransmitter in the central nervous system (CNS) and is mediated largely by the vesicular glutamate transporters (VGLUT1-3) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) types of glutamate receptors (GluR1-4) in mammals. In the present study, we determined the cDNA sequences of pigeon VGLUT2 and GluR1 and mapped the distribution of their mRNA in the pigeon CNS. The predicted amino acids of pigeon VGLUT2 and GluR1 showed a 93% identity to human VGLUT2 and GluR1 both. In situ hybridization autoradiograms showed VGLUT2 mRNA expression exclusively in the pallium of the telencephalon, and no expression in the subpallium. Within the diencephalon, VGLUT2 mRNA was more abundant in the thalamus than in the hypothalamus. Rich VGLUT2 mRNA expression was found in the optic tectum, nucleus mesencephalicus lateralis, pars dorsalis, nucleus isthmi, pars parvocellularis, isthmo-optic nucleus, pontine nuclei, and granular layer of the cerebellum. Moderate expression was noted in the cerebellar nuclei, vestibular nuclei, cochlear nuclei, inferior olivary nucleus, and gray matter of the spinal cord. GluR1 mRNA was expressed abundantly in the pallium and subpallium of the telencephalon, but it was poor in the diencephalon, midbrain, medulla, cerebellar cortex, and gray matter of the spinal cord. These results suggest that the cDNA sequences of VGLUT2 and GluR1 in the pigeon are comparable to those of VGLUT2 and GluR1 in mammals, respectively. The distribution of pigeon GluR1 mRNA resembles that of mammals, but the distribution of VGLUT2 mRNA resembles that of both VGLUT1 and VGLUT2 in mammals. J. Comp. Neurol. 511:658-677, 2008. (c) 2008 Wiley-Liss, Inc.

• Key role of mucosal primary afferents in mediating the inhibitory influence of capsaicin on vagally mediated contractions in the mouse esophagus.

  Authors: Ammar Boudaka, Jürgen Wörl, Takahiko Shiina, Shouichiro Saito, Yasuro Atoji, Haruo Kobayashi, Yasutake Shimizu, Tadashi Takewaki

  The Journal of veterinary medical science / the Japanese Society of Veterinary Science. 05/2007; 69(4):365-72.

  Transient receptor potential ion channel of the vanilloid type 1 (TRPV1)-dependent pathway, consisting of capsaicin-sensitive tachykininergic primary afferent and myenteric nitrergic neurons, wasTransient receptor potential ion channel of the vanilloid type 1 (TRPV1)-dependent pathway, consisting of capsaicin-sensitive tachykininergic primary afferent and myenteric nitrergic neurons, was suggested to mediate the inhibitory effect of capsaicin on the vagally mediated striated muscle contractions in the rat esophagus. These primary afferent neurons upon entering into the esophagus are distributed through the myenteric plexus, terminating either in the myenteric ganglia or en route to the mucosa where they branch into a delicate net of fine varicose fibers. Therefore, this study aimed to investigate whether the mucosal primary afferents are a main mediator for the capsaicin inhibitory influence on vagally mediated contractions in the mouse esophagus. For this purpose, the vagally induced contractile activity of a thoracic esophageal segment was measured in the circular direction with a force transducer. Vagal stimulation (30 microsec, 25 V, 1-50 Hz for 1 sec) produced monophasic contractile responses, whose amplitudes were frequency-dependent. These contractions were completely abolished by d-tubocurarine (5 microM) while resistant to atropine (1 microM) and hexamethonium (100 microM). Capsaicin (30 microM) significantly inhibited the vagally induced contractions in esophagi with intact mucosa while its effect on preparations without mucosa was insignificant. Additionally, immunocytochemistry revealed the presence of TRPV1-positive nerve fibers in the tunica mucosa. Taken together, we conclude that in the mouse esophagus, capsaicin inhibits the vagally mediated striated muscle contractions mainly through its action on mucosal primary afferents, which in turn activate the presumed inhibitory local reflex arc.

• Fiber connections of the compact division of the posterior pallial amygdala and lateral part of the bed nucleus of the stria terminalis in the pigeon (Columba livia).

  Authors: Yasuro Atoji, Shouichiro Saito, J Martin Wild

  The Journal of comparative neurology. 12/2006; 499(2):161-82.

  The compact division of the posterior pallial amygdala (PoAc) and lateral part of the bed nucleus of the stria terminalis (BSTL) are components of the limbic system in the pigeon brain. In thisThe compact division of the posterior pallial amygdala (PoAc) and lateral part of the bed nucleus of the stria terminalis (BSTL) are components of the limbic system in the pigeon brain. In this study, we examined the position and fiber connections of these two nuclei by using Nissl staining and tract-tracing methods. PoAc occupies a central division in the posterior pallial amygdala. BSTL faces the ventral horn of the lateral ventricle and extends between A 7.25 and A 10.50. PoAc and BSTL connect bidirectionally by the stria terminalis. PoAc connects reciprocally with two nuclear groups in the cerebrum: 1) a continuum consisting of the caudoventral nidopallium, lateral part of the caudoventral nidopallium (NCVl), subnidopallium beneath NCVl, and piriform cortex and 2) rostral areas of the hemisphere, including the frontolateral and frontomedial nidopallium and the densocellular part of the hyperpallium. Extratelencephalic projections of PoAc terminate in the dorsomedial thalamic nuclei and reach the lateral hypothalamic area via the hypothalamic part of the occipito-mesencephalic tract. BSTL also connects reciprocally with two main regions: 1) the same continuum as for PoAc projections, except the piriform cortex and 2) rostral areas of the hemisphere, including the olfactory tubercle and nucleus accumbens. Extratelencephalic reciprocal connections are with the substantia nigra, nucleus subceruleus dorsalis, parabrachial nucleus, locus coeruleus, and nucleus of the solitary tract. The dorsomedial subdivision of the hippocampal formation projects massively to PoAc and BSTL. These findings indicate that PoAc and BSTL are important components of an interconnected neural circuit involving widespread regions of the neuraxis and mediating limbic-visceral functions.

• Subdivision of the accessory olfactory bulb in the Japanese common toad, Bufo japonicus, revealed by lectin histochemical analysis.

  Authors: Shouichiro Saito, Naoto Kobayashi, Yasuro Atoji

  Anatomy and embryology. 11/2006; 211(5):395-402.

  Lectin binding patterns in the olfactory bulb of the Japanese common toad, Bufo japonicus, were examined using 21 types of lectin. Ten out of 21 lectins, WGA, s-WGA, LEL, STL, DBA, VVA, SJA, RCA-I,Lectin binding patterns in the olfactory bulb of the Japanese common toad, Bufo japonicus, were examined using 21 types of lectin. Ten out of 21 lectins, WGA, s-WGA, LEL, STL, DBA, VVA, SJA, RCA-I, PNA, and PHA-L, stained the olfactory nerve, the glomeruli in the main olfactory bulb (MOB), the vomeronasal nerve, and the glomeruli in the accessory olfactory bulb (AOB). The binding patterns of LEL, STL, DBA, and PHA-L subdivided AOB glomeruli into rostral and caudal regions, where LEL, STL, and DBA stained the rostral region more intensely than the caudal region, and PHA-L had the opposite effect. Another lectin, BSL-I, stained both AOB glomeruli and the vomeronasal nerve, but not MOB glomeruli or the olfactory nerve. This is the first report of histological subdivision in the AOB of an amphibian, which suggests that the AOB development in Bufo may be unique.

• Anatomy of the avian hippocampal formation.

  Authors: Yasuro Atoji, J Martin Wild

  Reviews in the neurosciences. 02/2006; 17(1-2):3-15.

  Increasing knowledge of the avian hippocampal formation (hippocampus and parahippocampal area) suggests that it plays a role in a variety of behaviors, such as homing, cache retrieving, visualIncreasing knowledge of the avian hippocampal formation (hippocampus and parahippocampal area) suggests that it plays a role in a variety of behaviors, such as homing, cache retrieving, visual discrimination, imprinting, and sexual behavior. Knowledge of the neural circuits in the hippocampal formation and its related areas or nuclei is important for the understanding of these functions. This review therefore describes the functional neuroanatomy of the avian hippocampal formations, i.e., its subdivisions, cytoarchitecture, and afferent and efferent connections. Evidence obtained by a combination of Nissl staining and tract-tracing shows that the pigeon hippocampal formation can be divided into seven subdivisions: dorsolateral (DL), dorsomedial (DM), triangular (Tr), V-shaped (V), magnocellular (Ma), parvocellular, and cell-poor regions. DL and DM can be further divided into dorsal and ventral, and lateral and medial portions, respectively. In the hippocampal formation, reciprocal connections are found between DL-DM, DL-Tr, DL-Ma, DM-Ma, DM-V, and Tr-V. Neurons in the V-shaped layer appear to be intrinsic neurons. Sensory inputs from higher order visual and olfactory stations enter DL and DM, are modified or integrated by intrinsic hippocampal circuitry, and the outputs are sent, via DL and DM, to various telencephalic nuclei, septum, and hypothalamus. The neural pathways indicate that the hippocampal formation plays a central role in the limbic system, which also includes the dorsolateral corticoid area, nucleus taeniae of the amygdala, posterior pallial amygdala, septum, medial part of the anterior dorsolateral nucleus of the thalamus, and the lateral mammillary nucleus. Connectional and comparative studies, including the use of kainic acid excitotoxicity, suggest that the V-shaped layer is comparable to the dentate gyrus of the mammalian hippocampal formation and DM to Ammon's horn and subiculum.

• Afferent and efferent connections of the dorsolateral corticoid area and a comparison with connections of the temporo-parieto-occipital area in the pigeon (Columba livia).

  Authors: Yasuro Atoji, J Martin Wild

  The Journal of comparative neurology. 06/2005; 485(2):165-82.

  The dorsolateral corticoid area (CDL) in the pigeon telencephalon is a thin, superficial part of the caudal pallium adjoining the medially situated hippocampal formation. To determine theThe dorsolateral corticoid area (CDL) in the pigeon telencephalon is a thin, superficial part of the caudal pallium adjoining the medially situated hippocampal formation. To determine the connectivity of CDL, and to distinguish CDL from the rostrally adjacent temporo-parieto-occipital area (TPO), injections of neural tracers were made into the caudal superficial pallium at various rostrocaudal levels. The results showed that injections caudal to A 6.75 (Karten and Hodos [1967] Baltimore: Johns Hopkins University Press) gave rise to reciprocal connections with subdivisions of the hippocampal formation, TPO, piriform cortex, posterior pallial amygdala, caudoventral nidopallium, densocellular part of the hyperpallium, lateral hyperpallium, frontolateral nidopallium, and lateral intermediate nidopallium. Of these, the hippocampal formation showed very strong connectivity with CDL, and projection fibers from CDL clearly separated the dorsomedial region of the hippocampal formation into lateral and medial portions. CDL projected directly to the olfactory bulb, but did not receive projections from it. In the diencephalon, CDL received efferents from a dorsal region of the medial part of the anterior dorsolateral nucleus of the thalamus, subrotundal nucleus, and internal paramedian nucleus of the thalamus. These findings suggest that CDL in the pigeon belongs to the limbic pallium and that in some respects it may be comparable to the mammalian cingulate cortex. In contrast, injections of tracers into the pallial surface at or rostral to A 7.00 showed marked differences in the pattern of both anterograde and retrograde labeling from that resulting from injections caudal to A 6.50, thereby indicating the approximate level of transition from CDL to TPO.

• A neurophysiological evidence of capsaicin-sensitive nerve components innervating interscapular brown adipose tissue.

  Authors: Keiichi Shinozaki, Yasutake Shimizu, Takahiko Shiina, Kazutoshi Nishijima, Yasuro Atoji, Hideki Nikami, Akira Niijima, Tadashi Takewaki

  Autonomic neuroscience : basic & clinical. 05/2005; 119(1):16-24.

  Neurophysiological basis for the heterogeneity of the nerve components in the brown adipose tissue (BAT) was examined in this experiment. Efferent nerve signals were recorded from the central cut endNeurophysiological basis for the heterogeneity of the nerve components in the brown adipose tissue (BAT) was examined in this experiment. Efferent nerve signals were recorded from the central cut end of the small nerve filament dissected from the nerve fibers innervating the interscapular BAT (IBAT). By focusing on qualitative aspects of observed compound action potentials (spikes), we found two distinctive types of spikes exhibited by the intercostal nerves innervating IBAT. The spikes mainly appeared upon sympathetic stimulations (cold stimulation and glucose administration) were characterized by low amplitude with relatively short duration (small spike) and their sensitivity to the ganglion blocker, hexamethonium (C6). On the other hand, the spikes seen throughout the experiments were characterized by high amplitude with long duration (large spike) and their insensitivity to C6. Since BAT is activated by cold and feeding via sympathetic nervous system, the small spikes seemed to be exhibited by sympathetic fibers. On the other hand, appearance of the large C6-insensitive spikes was strongly attenuated in capsaicin-desensitized rats. Even though the functional link between IBAT and C6 insensitive fibers remains unanswered, our results suggest that IBAT is under control of various nerve types including capsaicin-sensitive fibers in addition to the control of sympathetic nervous system.

• A comparative histological study on the distribution of striated and smooth muscles and glands in the esophagus of wild birds and mammals.

  Authors: Takahiko Shiina, Yasutake Shimizu, Noriaki Izumi, Yuji Suzuki, Makoto Asano, Yasuro Atoji, Hideki Nikami, Tadashi Takewaki

  The Journal of veterinary medical science / the Japanese Society of Veterinary Science. 02/2005; 67(1):115-7.

  Musculature and glands of the esophagus in various wild birds and mammals were examined histologically. Cervical and thoracic esophagi of all birds used (mallard, spot-billed duck, Ural owl andMusculature and glands of the esophagus in various wild birds and mammals were examined histologically. Cervical and thoracic esophagi of all birds used (mallard, spot-billed duck, Ural owl and Hodgson's hawk-eagle) were comprised of smooth muscle fibers only. In contrast, esophagi of the nutria, Japanese raccoon dog, common raccoon and Japanese marten consisted largely of striated muscle fibers. In the masked palm civet, Japanese macaque and bottlenose dolphin, esophageal muscle layers consisted of both striated and smooth muscle fibers. Esophageal glands were observed except for the nutria and masked palm civet. These results show a wide variety of the structural composition in the esophagus of wild animals, particularly mammals, examined in this study.

• Innervation of the rat trachea by bilateral cholinergic projections from the nucleus ambiguus and direct motor fibers from the cervical spinal cord: a retrograde and anterograde tracer study.

  Authors: Yasuro Atoji, Dwi Liliek Kusindarta, Nao Hamazaki, Akihisa Kaneko

  Brain research. 02/2005; 1031(1):90-100.

  A tract-tracer method was employed to examine the innervation of the rat trachea. Cholera toxin beta subunit (CTB) was injected into the following locations in separate groups of rats: (1) ventralA tract-tracer method was employed to examine the innervation of the rat trachea. Cholera toxin beta subunit (CTB) was injected into the following locations in separate groups of rats: (1) ventral trachea, (2) lateral trachea, (3) ventral trachea after the excision of the nodose ganglion, and (4) ventral trachea after the transection of C1-C2 spinal nerves. CTB injection in the ventral trachea showed bilateral labeling of neurons in the nucleus ambiguus (NA), medial subnucleus of the nucleus of the solitary nucleus, dorsal motor nucleus of the vagus (DMV), and lamina IX of C1-C6. CTB injection in the lateral trachea showed significant ipsilateral predominance of neuronal labeling in the NA and lamina IX of C1-C2 segments. CTB injection in rats after the excision of the nodose ganglion revealed no labeling in the ipsilateral DMV and NA and a significant reduction of neuronal labeling in C1. CTB injection in rats after the transection of C1-C2 spinal nerves showed a significant decrease in the number of labeled neurons in ipsilateral NA, C1, and C2 and no labeling of fibers in C1-C2. The combination of retrograde fluorogold labeling and choline acetyltransferase (ChAT) immunostaining revealed that all fluorogold-labeled neurons in the NA and lamina IX of C1-C2 colocalized with ChAT. The injection of biotinylated dextran amine in NA produced labeling in axonal terminals on postganglionic neurons, but not in other regions of the trachea. Our findings indicate that the rat trachea is innervated bilaterally by cholinergic motor neurons in NA and C1-C2, while those traveling through the spinal nerves project directly to the trachea.

• Taste buds and nerve fibers in the rat larynx: an ultrastructural and immunohistochemical study.

  Authors: Kazutoshi Nishijima, Yasuro Atoji

  Archives of histology and cytology. 10/2004; 67(3):195-209.

  We investigated the rat laryngeal taste buds and their innervation by electron microscopy and immunohistochemical methods. Taste buds were densely arranged in the surface facing the laryngeal cavityWe investigated the rat laryngeal taste buds and their innervation by electron microscopy and immunohistochemical methods. Taste buds were densely arranged in the surface facing the laryngeal cavity of the epiglottis, the aryepiglottic fold, and the cuneiform process of the arytenoid cartilages. The cells of the buds were classified into types I, II, III, and basal cells, the ultrastucture of which was almost the same as that previously reported in lingual taste buds. The type III cells that had synaptic contacts with nerve fibers were considered to be sensory cells. Immunohistochemical analysis revealed thick calbindin D28k-immunoreactive fibers and thin varicose fibers immunoreactive for calcitonin gene-related peptide or substance P in and around the taste bud. Serotonin-immunoreactive cells were also observed here. The results revealed the innervation pattern of laryngeal taste buds to be the same as that in lingual taste buds. Carbonic anhydrase (CA) is known to catalyze the hydration of CO2 and dehydration of H2CO3, and seems to be essential in CO2 reception. Immunoreactivity for CAI was detected in slender cells and that for CAIII was observed in barrel-like cells in the laryngeal taste buds. The pH-sensitive inward rectifier K+ (Kir) channel in the cell membrane may be involved in CO2 reception as well. CAII-reactive cells were also reactive to Kir4.1, PGP 9.5 and serotonin. Our results indicated that CAII and Kir4.1 are located in type III cells of the laryngeal taste buds, and supported the idea that the buds may be involved in the recognition of CO2.