B Halász

Semmelweis University, Budapest, Budapest fovaros, Hungary

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Publications (112)275.28 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: By means of double-label immunocytochemistry, authors studied the presence of estrogen receptor α (ER-α) protein in vesicular glutamate transporter 2 (VGluT2) protein-immunoreactive neurons in the female rat hypothalamus and amygdala. They examined colocalization of the 2 immunoreactive proteins in structures in which they found a significant overlap in the localization of the distribution of ER-α- and VGluT2-immunopositive nerve cells, namely in the medial preoptic area, the ventral subdivision of the ventromedial hypothalamic nucleus, and the medial amygdaloid nucleus. In the medial preoptic area, only 2.74 % of ER-α-immunoreactive neurons were VGluT2 positive, and conversely, 5 % of VGluT2-immunoreactive neurons contained ER-α immunofluorescent labeling. Highest degree of colocalization was detected in the ventral subdivision of the ventromedial hypothalamic nucleus, where 22.81 % of the ER-α-immunopositive neurons were VGluT2 immunoreactive and 37.14 % of the VGluT2-immunolabeled neurons contained ER-α-positive nucleus. In the medial amygdaloid nucleus, 15.38 % of the ER-α and 18.1 % of the VGluT2-immunoreactive neurons were double labeled. The colocalizations suggest that glutamatergic (VGluT2 protein immunoreactive) neurons are involved in the mediation of the action of estrogen on the rat brain.
    Experimental Brain Research 03/2013; · 2.22 Impact Factor
  • J Kiss, A Csáki, B Halász
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    ABSTRACT: The hypothalamic ventromedial nucleus is a prominent cell group, which is involved in the control of feeding, sexual behavior and cardiovascular function as well as having other functions. The nucleus receives inputs from various forebrain structures and has a dense glutamatergic innervation. The aim of the present investigations was to reveal the location of glutamatergic neurons in the telencephalon and diencephalon projecting to this hypothalamic cell group. [(3)H]d-aspartate retrograde autoradiography was used injecting the tracer into the ventromedial nucleus. We detected radiolabeled neurons in telencephalic structures including the lateral septum, bed nucleus of the stria terminalis and the amygdala, and in various diencephalic regions, such as the medial preoptic area, hypothalamic paraventricular nucleus, periventricular nucleus, anterior hypothalamic area, ventral premamillary nucleus, thalamic paraventricular and parataenial nuclei and in the hypothalamic ventromedial nucleus itself. Our observations are the first data on the location of glutamatergic neurons terminating in the hypothalamic ventromedial nucleus. The findings indicate that glutamatergic innervation of the ventromedial nucleus is very complex.
    Neuroscience 03/2011; 176:210-24. · 3.12 Impact Factor
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    ABSTRACT: The aim of the present investigations was to examine the involvement of the rich glutamatergic innervation of the hypothalamic suprachiasmatic nucleus, a key structure in the control of circadian rhythms, in the regulation of the diurnal fluctuations in plasma prolactin and corticosterone, and to test the involvement of the glutamatergic innervation of the mesencephalic dorsal raphe nucleus in the prolactin response induced by the suckling stimulus. By means of a mini-pump a non-NMDA receptor antagonist (6-cyano-7- nitroquinoxaline-2,3-dione disodium, CNQX) was microinfused between the two suprachiasmatic nuclei for 3 days and on the third day blood samples were taken at different time points of the day. CNQX inhibited the afternoon rise in plasma prolactin and corticosterone. In lactating rats CNQX, similarly to the NMDA antagonist MK-801, microinjected into the dorsal raphe nucleus significantly attenuated the prolactin response to the suckling stimulus. The findings indicate that the glutamatergic innervation of the suprachiasmatic nuclei is involved in the diurnal fluctuations in plasma prolactin and corticosterone levels, and the glutamatergic innervation of the dorsal raphe nucleus has a prominent role in the mediation of the suckling stimulus to the hypothalamus.
    Brain research bulletin 07/2009; 80(1-2):9-16. · 2.97 Impact Factor
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    ABSTRACT: This review summarizes the data obtained with the aid of the recently introduced dual viral tracing technique, which uses isogenic recombinants of pseudorabies virus that express unique reporter gene. This approach made possible to explore simultaneously neural circuits of two organs. The results of these studies indicate: (1) there are neurons innervating exclusively a given organ; (2) left-sided predominance in the supraspinal innervation of the endocrine glands (adrenal, ovary) studied, so far; (3) viral co-infection of neurons, i.e., special neuronal populations coexist in different brain areas that are transsynaptically connected with both paired endocrine and non-endocrine organs, endocrine glands and non-endocrine organs, and organs of bodily systems other than the endocrine one. The number of common neurons seems to be related to the need of coordinating action of different systems. The data on co-infection of neurons suggest that the central nervous system has the capacity to coordinate different organ functions via common brain neurons providing supraspinal innervation of the organs.
    Endocrine 06/2009; 36(2):179-88. · 3.53 Impact Factor
  • Frontiers in Systems Neuroscience 01/2009;
  • Agnes Csaki, Jozsef Kiss, Bela Halasz
    Frontiers in Systems Neuroscience 01/2009;
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    ABSTRACT: The hypothalamic suprachiasmatic nucleus (SCN), which plays a pivotal role in the control of circadian rhythms, consists of several neuronal subpopulations characterized by different neuroactive substances. This prominent cell group has a fairly rich glutamatergic innervation, but the cell types that are targeted by this innervation are unknown. Therefore, the purpose of the present study was to examine the relationship between the afferent glutamatergic axon terminals and the vasoactive intestinal polypeptide (VIP)-, arginine-vasopressin (AVP)- and gamma-aminobutyric acid (GABA)-positive neurons of the SCN. Glutamatergic elements were revealed via immunocytochemical double-labelling for vesicular glutamate transporter type 1 (VGluT1) and type 2 (VGluT2), and brain sections were imaged via confocal laser-scanning microscopy and electron microscopy. Numerous VGluT2-immunoreactive axons were observed to be in synaptic contact with VIP- and GABA-positive neurons, and only a few synapses were detected between VGluT2 boutons and AVP neurons. VGluT1 axon terminals exhibiting very moderate distribution in this cell group were observed to be in synaptic contact with chemically unidentified neurons. The findings provide the first morphological data on the termination of presumed glutamatergic fibres on chemically identified neurons of the rat SCN, and indicate that all three prominent cell types of the cell group receive glutamatergic afferents.
    European Journal of Neuroscience 12/2008; 28(9):1760-74. · 3.75 Impact Factor
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    ABSTRACT: Previous studies using the viral transneuronal tracing technique demonstrated central autonomic circuits involved in the innervation of the adrenal gland. Since increasing number of data indicate laterality in the neuroendocrine system, we aimed to investigate whether the supraspinal innervation of the adrenal gland exhibits asymmetry or not. The central circuitry involved in the innervation of the left and the right adrenal gland was studied in individual rats by dual transneuronal tracing using isogenic recombinant strains (Ba-DupGreen and Ba-Duplac expressing lacZ) of Bartha strain of pseudorabies virus. Viral infection of brain nuclei (dorsal vagal nucleus, nucleus of the solitary tract, caudal raphe nuclei, A5 cell group, hypothalamic paraventricular nucleus) from the left adrenal was more severe than that from the right organ. Dual-infected neurons were present both in the brain stem and in the hypothalamus. The results indicate a predominance in the supraspinal innervation of the left adrenal gland, and that each adrenal gland is innervated both by side-specific neurons and by neurons that project to both organs.
    Microscopy Research and Technique 08/2008; 71(7):503-9. · 1.59 Impact Factor
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    ABSTRACT: Previous studies using the viral transneuronal tracing technique demonstrated central autonomic circuits involved in the innervation of the adrenal gland and the ovary. Since the pattern of infection of central nervous system structures is similar after virus inoculation of the adrenal gland and the ovary, and, on the other hand, it is well documented that the activity of the hypothalamo–pituitary–adrenal axis exerts an inhibitory effect on the reproductive system, we investigated whether there are neurons that are transneuronally connected both with the adrenal gland and the ovary. The central circuitry involved in the innervation of the left adrenal and the left ovary was studied in individual rats by dual transneuronal tracing using isogenic recombinant strains (BDG and DS-RED) of Bartha strain of pseudorabies virus. Dual-infected neurons were detected in the ventrolateral medulla, nucleus of the solitary tract, caudal raphe nuclei, A5 cell group, and hypothalamic paraventricular nucleus. The results indicate that there are neurons in the central nervous system that contribute to the transneuronal innervation of both the adrenal gland and the ovary. The data suggest a new type of interaction, i.e. interaction at cellular level that might be involved in regulatory processes integrating the functional activity of the two organs.
    Brain research bulletin 01/2008; · 2.97 Impact Factor
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    ABSTRACT: The hypothalamic suprachiasmatic nucleus is the key structure of the control of circadian rhythms and has a rich glutamatergic innervation. Besides the presence of glutamatergic afferents, several findings also suggest the existence of glutamatergic efferents from the suprachiasmatic nucleus to its target neurons in various prominent hypothalamic cell groups. However, there is no direct neuromorphological evidence for the presence of glutamatergic neurons in the suprachiasmatic nucleus. Therefore, the purpose of the present investigations was to try to clarify this question. Immunocytochemistry was used at the light and electron microscopy level to identify vesicular glutamate transporter type 2 (VGluT2) immunopositive (presumed glutamatergic) neurons in the rat suprachiasmatic nucleus. In addition VGluT2 mRNA expression in neurons of the nucleus was also addressed with radioisotopic in situ hybridization. Both at the light and electron microscopy level we detected VGluT2 positive neurons, which did not contain GABA, vasoactive intestinal polypeptide or vasopressin. Further, we demonstrated the expression of VGluT2 mRNA in a few cells within the suprachiasmatic nucleus; these glutamatergic cells were distinct from somatostatin mRNA expressing neurons. As VGluT2 is a selective marker of glutamatergic neuronal elements, the present observations provide direct neuromorphological evidence for the presence of glutamatergic neurons in the cell group.
    Brain Research Bulletin 12/2007; 74(6):397-405. · 2.94 Impact Factor
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    ABSTRACT: The hypothalamic suprachiasmatic nucleus functioning as the principal circadian pacemaker in mammals, has a rich glutamatergic innervation. Nothing is known about the terminations of the glutamatergic fibres. The aim of the present investigations was to study the relationship between glutamatergic axon terminals and vasoactive intestinal polypeptide (VIP), GABA and arginine-vasopressin (AVP) neurons in the cell group. Double label immunocytochemistry was used and the brain sections were examined under the electron microscope. Vesicular glutamate transporter type 2 was applied as marker of the glutamatergic elements. Results - Glutamatergic fibers were detected in synaptic contact with GABAergic, VIP- and AVP-positive neurons forming asymmetric type of synapses. The findings are the first data on the synaptic contacts of glutamatergic axon terminals with neurochemically identified neurons in the suprachiasmatic nucleus.
    Ideggyógyászati szemle 04/2007; 60(3-4):166-8. · 0.35 Impact Factor
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    ABSTRACT: Testosterone secretion by Leydig cells is affected by interleukin-1beta (IL-1beta). The aim of the present study was to investigate whether partial denervation of the testis or local administration of a serotonin (5-HT) receptor antagonist could alter the changes in testicular steoidogenesis induced by IL-1beta. Intratesticular administration of IL-1beta was combined with vasectomy or local injection of ketanserin (5-HT type 2 receptor antagonist) in immature hemicastrated rats and the effect of the interventions on testicular steroidogenesis was studied. One day after treatment with local injection of IL-1beta induced a significant rise in testosterone secretion that could be prevented by vasectomy (that also means transection of the inferior spermatic nerve). In a model in which neither IL-1beta nor ketanserin interfered with steroidogenesis, administration of the receptor antagonist just prior to IL-1beta treatment significantly reduced testosterone secretion. Data indicate interaction between testicular nerves and IL-1beta action and interaction between testicular 5-HT2 receptors and local effect of IL-1beta on testosterone secretion.
    Autonomic Neuroscience 02/2007; 131(1-2):21-7. · 1.85 Impact Factor
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    ABSTRACT: Growth hormone-releasing hormone (GHRH) and somatostatin are the two main hypothalamic neurohormones, which stimulate or inhibit directly hypophysial growth hormone (GH) release. Majority of the GHRH neurons projecting to the median eminence is situated in the arcuate nucleus and the somatostatin neurons in the anterior periventricular nucleus. Data suggest that the excitatory amino acid glutamate may play an important role in the control of hypothalamic neuroendocrine neurons and processes including the control of GH. There is a dense plexus of glutamatergic fibres in the hypothalamic arcuate and anterior periventricular nucleus. The aim of the present studies was to examine the relationship of these fibres to the GHRH neurons in the arcuate nucleus and to somatostatin neurons in the anterior periventricular nucleus. Double-labelling immuno-electron microscopy was used. Glutamatergic structures were identified by the presence of vesicular glutamate transporter 2 (VGluT2) (a selective marker of glutamatergic elements) immunoreactivity. A significant number of VGluT2-immunoreactive boutons was observed to make asymmetric type of synapses with GHRH-immunostained nerve cells in the arcuate and with somatostatin neurons in the anterior periventricular nucleus. A subpopulation of somatostatin-immunoreactive neurons displayed also VGluT2 immunoreactivity. Our findings provide direct neuromorphological evidence for the view that the action of glutamate on GH release is exerted, at least partly, directly on GHRH and somatostatin neurons releasing these neurohormones into the hypophysial portal blood.
    Brain Research Bulletin 11/2006; 70(4-6):278-88. · 2.94 Impact Factor
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    ABSTRACT: The aim of the present investigations was to test the involvement of the glutamatergic innervation of the hypothalamic paraventricular nucleus in the prolactin response to stress. A non-NMDA (6-cyano-7-nitroquinoxaline-2,3-dione disodium, CNQX) or an NMDA glutamate receptor antagonist (dizocilpine hydrogen malate, MK-801) was injected bilaterally into the paraventricular nucleus of freely moving male rats and 15 min later the animals were exposed to formalin stress. Blood samples for prolactin and corticosterone were taken at different time points before and after administration of formalin. CNQX, when injected into the paraventricular nucleus, inhibited the formalin-induced rise in plasma prolactin and not significantly the increase in corticosterone. A similar effect was not observed if MK-801 was administered into the paraventricular nuclei or CNQX was injected outside the cell group. The findings indicate that the glutamatergic innervation of the paraventricular nucleus is involved in the mediation of the formalin-induced prolactin release.
    Neurochemical Research 03/2006; 31(2):201-8. · 2.13 Impact Factor
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    ABSTRACT: This article provides an overview of the increasing number of observations indicating that excitatory amino acids are involved in the control of prolactin secretion. The information available suggests that these amino acids exert a stimulatory action on hypophysial prolactin. Administration of a glutamate receptor agonist induces significant increase in prolactin release in rats, monkeys, and rams. In contrast, noncompetitive antagonists of N-methyl-D-aspartate receptors decrease plasma levels and attenuate the preovulatory surge of prolactin. It appears that the endogenous glutamatergic system participates not only in the regulation of basal secretion of prolactin, but also in the control of physiological prolactin responses induced by the suckling stimulus or by stress. Recent findings suggest that the glutamatergic innervation of the hypothalamic paraventricular nucleus is involved in the mediation of the neural signal of the suckling stimulus-induced prolactin release as well as in the mediation of the stress-induced release of prolactin.
    Endocrine 01/2006; 28(3):303-8. · 3.53 Impact Factor
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    ABSTRACT: Gonadal functions are governed by the hypothalamohypophysial system. Recent studies have demonstrated the existence of a multisynaptic neural pathway between the brain and the gonads. This review summarizes the morphological and physiological data that suggest the role of the brain-gonadal circuitry in the control of gonadal functions and discusses relevant clinical observations.
    Endocrine 01/2006; 28(3):309-18. · 3.53 Impact Factor
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    ABSTRACT: Abstract The hypothalamic arcuate nucleus contains a number of neurochemically different cell populations, among others neuropeptide Y (NPY)- and pro-opiomelanocortin (POMC)-derived peptide-expressing neurons; both are involved in the regulation of feeding and energy homeostasis, NPY neurons also in the release of hypophysiotropic hormones, sexual behaviour and thermogenesis. Recent observations indicate that there is a dense plexus of glutamatergic fibres in the arcuate nucleus. The aim of the present studies was to examine the relationship of these fibres to the NPY and POMC neurons in the arcuate nucleus. Double-label immunoelectron microscopy was used. Glutamatergic elements were identified by the presence of vesicular glutamate transporter 1 (VGluT1) or 2 (VGluT2) (selective markers of glutamatergic elements) immunoreactivity. A significant number of VGluT2-immunoreactive terminals was observed to make asymmetric type of synapses with NPY and with beta-endorphin (a marker of POMC neurons)-immunostained nerve cells of the arcuate nucleus. About 15% of VGluT2 synapsing terminals established asymmetric synapses with NPY-positive cells and more than 40% of VGlut2-positive terminals formed synapse on beta-endorphin-positive neurons. VGluT2-positive perikarya were also observed, part of them also contained beta-endorphin. Nerve terminals containing both VGluT2 and beta-endorphin were demonstrated in the cell group. Only very few VGluT1 fibres were detected. Our observations provide the first direct neuromorphological evidence for the existence of glutamatergic innervation of NPY and POMC neurons of the arcuate nucleus.
    European Journal of Neuroscience 05/2005; 21(8):2111-9. · 3.75 Impact Factor
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    ABSTRACT: Increased density of catecholaminergic nerves in the human polycystic ovary has been observed. The aim of the present study was to investigate the distribution of transsynaptically virus-labeled neurons in the central nervous system from the rat polycystic ovary to see whether is it different or not from that of cycling control rats. To induce a polycystic ovary, a single injection of estradiol valerate was given to adult female rats and 30 days later a neurotropic virus was injected into the right ovary. Rats were sacrificed 72 or 96 hours after viral infection. Weight of the ovaries of the estradiol valerate-treated rats was significantly lower compared to controls, and the histology of the ovaries of the treated rats displayed severely atretic large antral follicles. There was almost no viral labeling in the central nervous system from the ovaries showing precystic morphology, in spite of the fact that such altered organs are rich in nerve fibres. It is assumed that presently unidentified factors in the precystic ovary, presumably related to the link between the immune and the nervous system, might be involved in the infectivity of the virus, and thus be responsible for the lack of viral labeling from such an ovary.
    Microscopy Research and Technique 04/2005; 66(4):186-92. · 1.59 Impact Factor
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    ABSTRACT: The aim of the present investigations was to test the involvement of the glutamatergic innervation of the hypothalamic paraventricular nucleus in the prolactin response to the suckling stimulus. A non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-dione disodium (CNQX), or an NMDA receptor antagonist, dizocipine hydrogen malate (MK-801), was injected bilaterally into the hypothalamic paraventricular nucleus of lactating freely moving rats before the end of a 4-h separation of the dams from their pups. The litters were then returned. Blood samples for prolactin were taken at different time points. The effect of the non-NMDA receptor antagonist was also tested in animals receiving the drug bilaterally into the dorsomedial nucleus area or the arcuate nucleus. Bilateral injection of CNQX into the paraventricular nucleus blocked the elevation in plasma prolactin concentration induced by the suckling stimulus. In contrast, bilateral administration of the NMDA receptor antagonist MK-801 into the paraventricular nucleus or bilateral injection of CNQX into the dorsomedial nucleus area or the arcuate nucleus did not interfere with the prolactin response to the suckling stimulus. The findings indicate that the glutamatergic innervation of the paraventricular nucleus is involved in the mediation of the neural signal of the suckling stimulus inducing prolactin release.
    Brain Research Bulletin 04/2005; 65(2):163-8. · 2.94 Impact Factor
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    ABSTRACT: Using the transneuronal viral tracing method, the central nervous system (CNS) connections of the uterine horn were studied in virgin, pregnant, and in lactating rats. The frequency of viral labeling in the brain and the distribution of virus-infected neurons from the uterine horn were compared among groups. There was a marked difference in the frequency of viral labeling in the brain stem. In virgin rats more than half of the brain stems (5 out of 9) were labeled. In contrast, in pregnant animals viral-labeled neurons were detected in only a few cases (3 out of 16) and almost each brain stem of the lactating group was labeled (12 out of 13). A similar, less marked difference was observed in the hypothalamus. The pattern of distribution of infected neurons was similar in each group. In the brain stem, the nucleus of the solitary tract, dorsal motor nucleus of the vagus, area postrema, gigantocellular and paragigantocellular nucleus, ventrolateral medulla, A5 cell group, and caudal raphe nuclei were the most frequently labeled structures. In the diencephalon, viral-infected neurons were detected primarily in the hypothalamic paraventricular nucleus. The telencephalon was devoid of infected cells. Data suggest that the CNS control of the uterine horn varies depending on reproductive status. The low frequency of brain labeling in pregnant rats may be related to the almost complete lack of sympathetic fibers in the uterus prior to parturition and the very high frequency of labeling in lactating animals to the postpartum hyperinnervation of the uterus.
    Microscopy Research and Technique 04/2004; 63(4):244-52. · 1.59 Impact Factor

Publication Stats

1k Citations
275.28 Total Impact Points

Institutions

  • 1974–2013
    • Semmelweis University
      • • Department of Human Morphology and Developmental Biology
      • • Department of Anatomy, Histology and Embryology
      Budapest, Budapest fovaros, Hungary
  • 1990–2008
    • Hungarian Academy of Sciences
      • • MTA Institute of Experimental Medicine
      • • Department of Endocrine Neurobiology
      Budapest, Budapest fovaros, Hungary
  • 1972
    • University of Pécs
      Fuenfkirchen, Baranya county, Hungary