Sayaka Arata

Olfactory signals mediate social buffering of conditioned fear responses in male rats.

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.

An approach to canine behavioural genetics employing guide dogs for the blind.

The purpose of this study was to attempt to find related variables of the canine genome with behavioural traits of dogs maintained and tested in a guide dog facility which provided a relatively uniform environment. The study involved 81 Labrador Retrievers that were being trained as guide dogs. Each dog was taken on walk-out sessions in which the trainer weekly recorded observations that were related to behavioural traits. The records were subjected to key-word analysis of 14 behaviour-related words. A factor analysis on the appearance rate of the 14 key words or phrases resulted in the extraction of six factors that accounted for 67.4% of the variance. Factor 1, referred to as aggressiveness, was significantly related to the success or failure of the dog in qualifying as a guide dog, and was also related to the variable of litter identification. Factor 2, referred to as distraction, was related to the variable of trainer. Factor 3, activity level, was related to the variable of sex, and was significantly related to the polymorphisms of c.471T>C in the solute carrier family 1 (neuronal/epithelial high affinity glutamate transporter) member 2 gene and c.216G>A in the catechol-O-methyltransferase gene. The involvement of polymorphisms c.471T>C and c.216G>A in behavioural patterns related to activity level is similar to comparable genetic studies in other mammalian species. These results contribute to a greater understanding of the role of these genes in behaviour.

c-Fos expression during the modulation of sexual behavior by an alarm pheromone.

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 60 min 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.

Molecular epidemiology of canine GM1 gangliosidosis in the Shiba Inu breed in Japan: relationship between regional prevalence and carrier frequency

BackgroundCanine GM1 gangliosidosis is a fatal disease in the Shiba Inu breed, which is one of the most popular traditional breeds in Japan and is maintained as a standard breed in many countries. Therefore, it is important to control and reduce the prevalence of GM1 gangliosidosis for maintaining the quality of this breed and to ensure supply of healthy dogs to prospective breeders and owners. This molecular epidemiological survey was performed to formulate an effective strategy for the control and prevention of this disease.ResultsThe survey was carried out among 590 clinically unaffected Shiba Inu dogs from the 8 districts of Japan, and a genotyping test was used to determine nation-wide and regional carrier frequencies. The number and native district of affected dogs identified in 16 years from 1997 to June 2013 were also surveyed retrospectively. Of the 590 dogs examined, 6 dogs (1.02%, 6/590) were carriers: 3 dogs (2.27%, 3/132) from the Kinki district and the other 3 dogs from the Hokkaido, Kanto, and Shikoku districts. The retrospective survey revealed 23 affected dogs, among which, 19 dogs (82.6%) were born within the last 7 years. Of the 23 affected dogs, 12 dogs (52.2%) were from the Kinki district. Pedigree analysis demonstrated that all the affected dogs and carriers with the pedigree information have a close blood relationship.ConclusionsOur results showed that the current carrier frequency for GM1 gangliosidosis is on the average 1.02% in Japan and rather high in the Kinki district, which may be related to the high prevalence observed over the past 16 years in this region. This observation suggests that carrier dogs are distributed all over Japan; however, kennels in the Kinki district may face an increased risk of GM1 gangliosidosis. Therefore, for effective control and prevention of this disease, it is necessary to examine as many breeding dogs as possible from all regions of Japan, especially from kennels located in areas with high prevalence and carrier frequency.

Analysis of Associations between Behavioral Traits and Four Types of Aggression in Shiba Inu

ABSTRACT Canine aggression is one of the behavioral problems for which veterinary behaviorists are most frequently consulted. Despite this, the classification of canine aggression is controversial, and there are several classification methodologies. While the etiology of canine aggression differs among the types of aggression, the behavioral background underlying aggression is not well understood. Behavior trait-based evaluation of canine aggression would improve the effectiveness and efficiency of managing canine aggression problems. We developed a questionnaire addressing 14 behavioral items and items related to four types of canine aggression (owner-, child-, stranger- and dog-directed aggression) in order to examine the associations between behavioral traits and aggression in Shiba Inu. A total of 400 Shiba Inu owners recruited through dog events (n=134) and veterinary hospitals (n=266) completed the questionnaire. Factor analysis sorted the behavioral items from both the event and clinic samples into four factors: “sociability with humans,” “reactivity to stimuli,” “chase proneness” and “fear of sounds.” While “reactivity to stimuli” correlated significantly positively with all of the four types of aggression (P=0.007 to <0.001), “sociability with humans” correlated significantly negatively with child- and stranger-directed aggression (P<0.001). These results suggest that the behavioral traits involved in canine aggression differ among the types of aggression and that specific behavioral traits are frequently simultaneously involved in several types of aggression.

Microsatellite loci analysis for individual identification in Shiba Inu

Eighteen autosomal microsatellite loci were examined using 275 Shiba Inus in Japan. Eighteen dogs representing eight trios were obtained from four breeders to calculate mutation rates, and 257 dogs kept by owners were collected through veterinary clinics throughout Japan to calculate population genetic parameters and estimate discrimination power. After two loci (INU005 and AHTk253) were excluded, average expected heterozygosity (He), polymorphic information content (PIC) and fixation index (F) were 0.665, 0.623 and 0.046, respectively. The combined power of discrimination over the 16 microsatellite markers was more than 0.9999. Therefore, it is suggested that these 16 microsatellite loci recommended by the International Society for Animal Genetics (ISAG) are applicable for individual identification and parentage testing of domestic Shiba Inu in Japan.