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ABSTRACT: Previously, we have demonstrated that the alarm pheromone deteriorates sexual behavior in male rats, which was blocked by pretreatment with a corticotrophin-releasing hormone (CRH) antagonist. Studies have shown that an opioid antagonist blocked the deterioration of male sexual behavior following intracerebroventricular administration of CRH. Therefore, possibly, the pheromone effects could also be mediated by the opioid system. In this study, we pretreated rats with naloxone, an opioid receptor antagonist, and examined the following sexual behavior modulations in male rats that were exposed to the alarm pheromone. Naloxone blocked the deterioration of sexual behavior in a dose-dependent manner. On the basis of these data and the results of the previous study, we conclude that the alarm pheromone activates the CRH system, which then activates the opioid system, to deteriorate male sexual behavior.
Journal of Veterinary Medical Science 01/2013; · 0.85 Impact Factor
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ABSTRACT: In social animals, the presence of an affiliative conspecific alleviates acute stress responses, and this is called social buffering. We previously reported that social buffering mitigates the fear responses of male rats to auditory conditioned stimuli that had been paired with foot shocks. Subsequent studies revealed that signals that are perceived by the main olfactory epithelium are important for social buffering. Because olfactory signals are the signal perceived by the main olfactory epithelium, we hypothesized that we could induce the social buffering of conditioned fear responses by presenting olfactory signals that were derived from a conspecific. In order to test this hypothesis, we exposed fear-conditioned subjects to a conditioned stimulus either in a clean test box or in a test box that was odorized by keeping a conspecific in it as an odor donor beforehand. When the subjects were tested in the clean test box, they showed behavioral fear responses and enhanced Fos expression in the paraventricular nucleus. In contrast, the presence of conspecific olfactory signals blocked these fear responses and Fos expression. These results suggested that olfactory signals suppress conditioned fear responses. Fos expression in the posteromedial region of the olfactory peduncle and amygdala suggested that this suppression involves the same neural mechanisms as those of social buffering. Taken together, we concluded that olfactory signals mediate the social buffering of conditioned fear responses.
Behavioural brain research 11/2012; · 3.22 Impact Factor
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ABSTRACT: We previously demonstrated that an alarm pheromone released by male Wistar rats evokes several physiological and behavioral responses in other rats. In addition to these responses, the alarm pheromone increased the number of mounts needed for an ejaculation and decreased the hit rate (number of intromissions/sum of the mounts and intromissions). These effects were blocked by pretreatment by a corticotropin releasing hormone (CRH) receptor antagonist. However, the neural mechanisms underlying the modulation of sexual behavior by this pheromone remain unknown. In this study, we measured c-Fos expression in 22 brain sites in pheromone-exposed male rats 60min after their first ejaculation. The paraventricular nucleus was double-stained for c-Fos and CRH to determine which neurons were activated by the pheromone. The alarm pheromone increased the number of mounts, decreased the hit rate, and increased the number of cells double-labeled for c-Fos and CRH in the paraventricular nucleus. These results indicate that the alarm pheromone is a stressor. Pheromone-exposed rats also showed significantly increased c-Fos expression in the anterior division medial group, anterior division lateral group, and posterior division of the bed nucleus of the stria terminalis, the anterior part of the medial and the basolateral region of the amygdala, and the nucleus paragigantocellularis. Based on these results and previous findings, we propose that the alarm pheromone modifies sexual behavior by inducing CRH release that indirectly activates the nucleus paragigantocellularis.
Behavioural brain research 09/2012; 237C:230-237. · 3.22 Impact Factor
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ABSTRACT: Guide dogs help visually impaired persons both physically and psychologically. More than half of all candidate dogs do not qualify, mainly for behavioral reasons. Improved training efficacy is desirable, and earlier prediction of qualification-related traits would be beneficial. In a previous study, we identified 'Distraction', assessed during the training period, as an important behavioral trait for judging the qualification of guide dogs at the Japan Guide Dog Association. As a second step, we aimed to develop an index that can predict during the puppy period. In this study, candidate guide dogs, 5-month-old Labrador retrievers, were assessed by puppy raisers using a newly developed questionnaire that consisted of 20 items. The same dogs were assessed later, at 15 months, by trainers to determine 'Distraction'. In principal components analysis, 9 items, including excitability toward strangers, initiative while out for a walk, and exploration, composed the first principal component (PC1). When we compared PC1 points with 'Distraction' points, the two categories were positively correlated (n=110, r(s)=0.31, P=0.0009). Although the accuracy of the questionnaire should be increased, the results of the present study suggest that it may be possible to assess and predict 'Distraction', which is associated with disqualification for guide dogs, early in the puppy-raising period.
Journal of Veterinary Medical Science 09/2012; · 0.85 Impact Factor
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ABSTRACT: The aim of this study was to investigate the risk factors for tail chasing behaviour that occurs when a dog spins in tight circles to chase its tail, sometimes biting it. The behaviour is a sign of canine compulsive disorder (CD). A questionnaire about tail chasing behaviour and general information about the animals was used to collect data on seven breeds of pet dogs. The data were gathered at a dog event and at veterinary practices. To determine which variables were associated with tail chasing behaviour, stepwise multiple regression analyses were performed. Regardless of cohort, 'breed' and 'source of acquisition' were significantly associated with tail chasing behaviour. Using a chi-square test, the association between 'source of acquisition' and the behaviour was examined separately in two breeds (Shiba inu and Dachshund) that had the largest number of individuals chasing their tails accompanied by biting and/or growling at them. This factor showed a significant and consistent association across the two breeds. With respect to the risk factors of 'breed' and 'source of acquisition', high percentages of Shiba inu and dogs originating from pet stores were included in the group chasing their tails with biting and/or growling. The results suggest that distinct risk factors exist for tail chasing behaviour and such factors appear to be regulated by both genetics and the environment.
The Veterinary Journal 10/2011; 192(3):445-8. · 2.24 Impact Factor
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ABSTRACT: Guide dogs for the blind help blind people physically and mentally in their daily lives. Their qualifications are based on health, working performance and temperament; approximately 70% of dogs that fail to qualify are disqualified for behavioral reasons. In order to achieve early prediction of qualification, it would be essential as the first step to identify important temperament traits for guide dogs. Therefore, we administered a questionnaire consisting of 22 temperament items to experienced trainers to assess candidate dogs at the Japan Guide Dog Association after three months of training, which was at least three months prior to the final success (qualified as a guide dog) or failure (disqualified for behavioral reasons) judgment. Factor analyses of question items stably extracted three factors with high internal consistency, Distraction, Sensitivity and Docility. When we compared factor points between successful dogs and failed dogs, the successful dogs showed significantly and consistently lower Distraction points and higher Docility points. Additionally, Distraction points could predict qualification with 80.6% accuracy and detect 28.2% of the failed dogs that had higher Distraction points than any of the successful dogs. Of the nine question items not included in the three factors, two items (;Aggression' and ;Animal interest') were consistently associated with qualification. These results suggest that Distraction is stably assessable and has the strongest impact on success or failure judgment; therefore, it will be the first target to establish a behavioral test that may lead to early prediction of guide dog qualification.
Journal of Veterinary Medical Science 12/2009; 72(5):539-45. · 0.85 Impact Factor
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ABSTRACT: Glutamate decarboxylase (GAD) is the primary enzyme in the brain that catalyzes the synthesis of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter. There are two isoforms named according to their molecular weights, GAD67 and GAD65, which are encoded by GAD1 and GAD2, respectively. To investigate the association between GAD genes and temperament in domestic dogs, Canis familiaris, we sequenced the full lengths of the coding regions of these genes and identified three single nucleotide polymorphisms (SNPs) in GAD1 and one in GAD2. When comparing genotype and allele frequencies of SNPs among five breeds with different behavioral traits, statistically significant interbreed differences were observed for three SNPs in GAD1. These results suggest that GAD1 SNPs may be useful for behavioral genetic studies in dogs.
Journal of Veterinary Medical Science 11/2008; 70(10):1107-10. · 0.85 Impact Factor
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ABSTRACT: Monoamine transporters have roles to regulate the monoamine concentrations in synaptic clefts in the central nervous system and are the targets of antidepressants and psychostimulants. They include transporters for norepinephrine, dopamine and serotonin, which are encoded by the SLC6A2, SLC6A3, and SLC6A4 genes, respectivily. We sequenced the full lengths of the coding regions of these genes for dogs and identified four single nucleotide polymorphisms (SNPs) in SLC6A2 and four in SLC6A3. One SLC6A3 SNP was non-synonymous and caused an amino acid substitution from threonine to serine. The genotype frequencies of these polymorphisms differed significantly among five breeds with different behavioral traits, suggesting that novel SLC6A2 and SLC6A3 SNPs would provide additional useful information for behavioral genetic studies in dogs.
Journal of Veterinary Medical Science 10/2008; 70(9):971-5. · 0.85 Impact Factor
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ABSTRACT: Transforming growth factor-beta1 (TGF-beta1), an inflammatory cytokine, plays a role in tissue fibrosis, such as glomerular sclerosis and tubulointerstitial fibrosis of the kidneys. In the present study, the urinary TGF-beta1 level of cats diagnosed with chronic renal failure (CRF) was measured to investigate its relationship to the pathogenesis of feline CRF. Urinary TGF-beta1 levels (TGF-beta1/creatinine ratio) were significantly increased compared with healthy controls, whereas serum levels of TGF-beta1 were not. These results indicate that TGF-beta1 is expressed in the kidneys of CRF cats, and that it was reflected in the urinary TGF-beta1 level. Therefore, TGF-beta1 may play a role in feline CRF, and urinary TGF-beta1 could be used as a clinical marker for renal fibrosis.
Journal of Veterinary Medical Science 01/2006; 67(12):1253-5. · 0.85 Impact Factor
