Approach/avoidance behavior to novel objects is correlated with the serotonergic and dopaminergic systems in the brown rat (Rattus norvegicus).

The brown rat (Rattus norvegicus) is known to show three types of behavioral responses to novel objects. Whereas some rats are indifferent to novel objects, neophobic and neophilic rats show avoidance and approach behavior, respectively. Here, we compared the dopaminergic, serotonergic, and noradrenergic systems immunohistochemically among these rats. Trapped wild rats and laboratory rats were first individually exposed to the novel objects in their home cage. Wild rats were divided into neophobic and indifferent rats depending on their behavioral responses. Similarly, laboratory rats were divided into neophilic and indifferent rats. Consistent with the behavioral differences, in the paraventricular nucleus of the hypothalamus, Fos expression in corticotropin-releasing hormone-containing neurons was higher in the neophobic rats than in the indifferent rats. In the anterior basal amygdala, the neophobic rats showed higher Fos expression than the indifferent rats. In the posterior basal amygdala, the neophobic and neophilic rats showed lower and higher Fos expressions than the indifferent rats, respectively. When we compared the neuromodulatory systems in the dorsal raphe, the number of serotonergic neurons and Fos expression in serotonergic neurons increased linearly from neophobic to indifferent to neophilic rats. In the ventral tegmental area, Fos expression in dopaminergic neurons was higher in the neophilic rats than in the indifferent rats. These results demonstrate that approach/avoidance behavior to novel objects is correlated with the serotonergic and dopaminergic systems in the brown rat. We propose that the serotonergic system suppresses avoidance behavior while the dopaminergic system enhances approach behavior to novel objects.

Naloxone increases conditioned fear responses during social buffering in male rats.

Social buffering is the phenomenon in which the presence of an affiliative conspecific mitigates stress responses. We previously demonstrated that social buffering completely ameliorates conditioned fear responses in rats. However, the neuromodulators involved in social buffering are poorly understood. Given that opioids, dopamine, oxytocin and vasopressin play an important role in affiliative behaviour, here, we assessed the effects of the most well-known antagonists, naloxone (opioid receptor antagonist), haloperidol (dopamine D2 receptor antagonist), atosiban (oxytocin receptor antagonist) and SR49059 (vasopressin V1a receptor antagonist), on social buffering. In Experiment 1, fear-conditioned male subjects were intraperitoneally administered one of the four antagonists 25 min prior to exposure to a conditioned stimulus with an unfamiliar non-conditioned rat. Naloxone, but not the other three antagonists, increased freezing and decreased walking and investigation as compared with saline administration. In Experiment 2, identical naloxone administration did not affect locomotor activity, anxiety-like behaviour or freezing in an open-field test. In Experiment 3, after confirming that the same naloxone administration again increased conditioned fear responses, as done in Experiment 1, we measured Fos expression in 16 brain regions. Compared with saline, naloxone increased Fos expression in the paraventricular nucleus of the hypothalamus and decreased Fos expression in the nucleus accumbens shell, anterior cingulate cortex and insular cortex and tended to decrease Fos expression in the nucleus accumbens core. Based on these results, we suggest that naloxone blocks social buffering of conditioned fear responses in male rats.

An appeasing pheromone ameliorates fear responses in the brown rat (Rattus norvegicus).

The brown rat (Rattus norvegicus) is one of the major animals both in the laboratory and in urban centers. Brown rats communicate various types of information using pheromones, the chemicals that mediate intra-species communication in minute amounts. Therefore, analyses of pheromones would further our understanding of the mode of life of rats. We show that a minute amount of 2-methylbutyric acid (2-MB) released from the neck region can ameliorate fear responses both in laboratory rats and in wild brown rats. Based on these findings, we conclude that 2-MB is an appeasing pheromone in the brown rat. A better understanding of rats themselves would allow us to perform more effective ecologically based research on social skills and pest management campaigns with low animal welfare impacts, which might contribute to furthering the advancement of science and improving public health.

Clinical usefulness of the hold-and-drag closure using the SB clip for large mucosal defects after colorectal endoscopic submucosal dissection.

BACKGROUND: Endoscopic clip closure of mucosal defects after colorectal endoscopic submucosal dissection (ESD) reduces the risk of postoperative adverse events, but achieving complete closure for large mucosal defects can be difficult. The aim of this study was to evaluate the effectiveness of the hold-and-drag closure using an SB clip compared with that of the conventional closure for mucosal defects after colorectal ESD. METHODS: Eighty-four consecutive colorectal lesions resected by ESD at the Hiroshima Asa Citizens Hospital were registered and randomly allocated to two groups (Group A: SB clip, Group B: EZ clip), and then endoscopic closures were performed. We crossed-over to the SB clip in situations where the initial closure using an EZ clip was unsuccessful in achieving complete closure. Outcomes were compared and analyzed. RESULTS: Forty-two lesions were randomly assigned to groups A and B. The complete closure rate was significantly higher in group A, especially in resected specimens with a diameter of 30 mm or more. Twelve lesions that failed complete closure in group B were changed to SB clips, and 95% of the whole of group B were successfully closed. There were no significant differences in procedural time, number of clips, and cost of clips between groups A and B. CONCLUSION: Compared with the conventional closure, the hold-and-drag closure using an SB clip is a more suitable method for complete closure, especially for large mucosal defects of 30 mm or more. Furthermore, this is a simpler and more economical compared to a zipper closure using EZ clips.

Glutamatergic Projections from the Posterior Complex of the Anterior Olfactory Nucleus to the Amygdala Complexes.

Social buffering is a phenomenon where stress responses are ameliorated by an affiliative conspecific. Our previous findings suggest that the posterior complex of the anterior olfactory nucleus (AOP) is well positioned to participate in the neural mechanisms underlying social buffering. However, the lack of anatomical information prevents us from further estimating the role of the AOP. Here, we obtained anatomical information regarding the AOP in male rats. In Experiment 1 (n = 5), among 4',6-diamidino-2-phenylindole-positive cells in the AOP, the proportion of glutamic acid decarboxylase 67 (GAD67)-positive cells was 13.8% ± 1.2%. In Experiment 2 (n = 5), among the cells that were labeled by a retrograde tracer injected into the basolateral complex of the amygdala (BLA), the proportion of GAD67-positive cells was 18.6% ± 0.8%. In Experiment 3 (n = 5), we demonstrated the existence of cells that were labeled by the retrograde tracer injected into the posterior part of the medial amygdala (MeP), mostly into the ventral part of the MeP. In addition, the proportion of GAD67-positive cells among the tracer-labeled cells was 21.7% ± 1.7%. In Experiment 4 (n = 3), the retrograde tracers were injected into the BLA and MeP, mostly into the ventral part of the MeP. The proportion of double-labeled cells among the tracer-labeled cells was 2.1% ± 1.2%. Taken together, these results suggest that the AOP is predominantly composed of glutamatergic neurons. In addition, the AOP sends mutually independent glutamatergic-predominant projections to the BLA and MeP.

Parallel Olfactory Systems Synergistically Activate the Posteroventral Part of the Medial Amygdala Upon Alarm Pheromone Detection in Rats.

In rats, a mixture of hexanal and 4-methylpentanal is a main component of the alarm pheromone. When detected by the main olfactory system (MOS) and the vomeronasal system, respectively, they activate the anterior part of the bed nucleus of the stria terminalis (BNSTa). Therefore, the information from the two olfactory systems is expected to be integrated before being transmitted to the BNSTa. To specify the integration site, we examined Fos expression in 16 brain regions in response to water (n = 10), hexanal (n = 9), 4-methylpentanal (n = 9), the mixture (n = 9), or the alarm pheromone (n = 9) in male rats. The posteroventral part of the medial amygdala showed increased Fos expression to hexanal and 4-methylpentanal. The expression was further increased by the mixture. Therefore, this region is suggested as the integration site. In addition, the BNSTa, paraventricular nucleus of the hypothalamus, and anteroventral, anterodorsal, and posterodorsal parts of the medial amygdala were suggested to be located downstream of the integrated site because only the mixture increased Fos expression. We suggest that the posterolateral part of the cortical amygdala is upstream of the integration site in the MOS because all stimuli increased Fos expression. The posterior part of the bed nucleus of the stria terminalis and posteromedial part of the cortical amygdala were suggested as being located upstream in the vomeronasal system because 4-methylpentanal and the mixture increased Fos expression. These results provide information about the neural pathway underlying the alarm pheromone effects.

The strain of unfamiliar conspecifics affects stress identification in rats.

Humans show distinct social behaviours when we evaluate an individual as being a member of the same group and recognize social similarity to the individual. One example is more accurate identification of emotion in that individual. Our previous studies proposed that rats recognize social similarity to certain strains of unfamiliar rats. It is therefore possible that the strain of unfamiliar conspecifics affects stress identification in rats. Wistar subject rats were allowed to explore a pair of unfamiliar Wistar, Sprague-Dawley (SD), Long-Evans (LE), or Fischer344 (F344) stimulus rats. To induce differences in stress, one of the stimulus rats had received foot shocks immediately before the test. It was found that the subjects showed biased interaction towards the shocked Wistar and SD stimulus rats, but not toward the shocked LE or F344 stimulus rats. Subsequent experiments confirmed that the biased interaction towards the shocked Wistar and SD stimulus rats was driven by stress in these stimulus rats. In addition, the lack of biased interaction towards the shocked LE and F344 stimulus rats did not appear to be due to procedural reasons. The experiment using LE subject rats further confirmed that the shocked LE stimulus rats emitted distress signals. These results suggested that Wistar rats could identify stress in unfamiliar Wistar and SD rats, but not in unfamiliar LE or F344 rats. Therefore, rats appear to recognize social similarity to certain unfamiliar strains of rats.

Mapping of c-Fos expression in the medial amygdala following social buffering in male rats.

Social buffering is the phenomenon in which an affiliative conspecific (associate) ameliorates stress responses of a subject. We previously found that social buffering in Wistar subject rats is induced if the strain of the associate is Wistar or a strain derived from Wistar rats. In the present study, we assessed the possible role of medial amygdala (Me) in this strain-dependent induction of social buffering. The subjects were exposed to the conditioned stimulus (CS) that had been paired or unpaired with a foot shock either alone, with an unfamiliar Wistar associate, or with an unfamiliar Fischer 344 (F344) associate. We found that the Wistar associates, but not F344 associates, ameliorated increased freezing and Fos expression in the paraventricular nucleus of the hypothalamus and lateral amygdala caused by the CS. In addition, Fos expression in the posterior complex of the anterior olfactory nucleus and lateral intercalated cell mass of the amygdala was increased simultaneously. These results suggest that Wistar associates, but not F344 associates, induced social buffering. In the Me, we did not find any differences associated with stress responses or amelioration of stress responses. In contrast, a comparison among the unpaired subjects found that the Wistar associates, but not F344 associates, increased exploratory behavior and Fos expression in the posteroventral subdivision of the Me (MePV). Based on these results, we propose that the MePV is involved in the recognition of social similarity with the associates. Taken together, the present study provides information about the possible role of Me in social buffering.

Association Reaction of Gaseous C2H4 in Femtosecond Laser Filaments Studied by Time-of-Flight Mass Spectrometry.

Association reactions by femtosecond laser filamentation in gaseous C2H4 were studied by time-of-flight mass spectrometry of neutral reaction products. Direct sampling from the reaction cell to a mass spectrometer via a differential pumping stage allowed the identification of various hydrocarbon molecules C n H m with n = 3-7 and m = 4-7, which includes species not observed in the previous studies. It was found that products containing three and four carbon atoms dominate the mass spectrum with smaller yields for higher-mass species, suggesting that carbon chain growth proceeds through the reaction with C2H4 in the reaction cell. The product distribution showed a clear dependence on the laser pulse energy for filamentation.

Pyogenic Granuloma Mimicking T1 Colorectal Carcinoma.

Pyogenic granuloma (PG), a benign capillary hemangioma, is extremely rare in the colon. Here, we present a case of PG that was difficult to distinguish from T1 (deep submucosal invasive) colorectal carcinoma. A 57-year-old woman with no remarkable history was referred to us for a detailed investigation of a positive fecal occult blood test. Colonoscopy revealed a reddish, irregular-shaped, protruding lesion (5 mm) in the rectum. We performed endoscopic mucosal resection of the lesion as total excisional biopsy because T1 colorectal carcinoma was suspected, despite the lesion's small size after observation by magnifying endoscopy. Histologically, the protruding lesion mainly consisted of numerous capillaries lined with plump and flat endothelial cells without signs of malignancy. Colorectal carcinoma, on the other hand, is composed of tall columnar atypical epithelial cells showing neoplastic proliferation. Thus, cell morphology is completely different between PG and colorectal carcinoma. The final diagnosis was colonic PG with a negative vertical margin. In conclusion, physicians should be aware of a colorectal protruding lesion devoid of malignant potential, as in this case, where the lesion was difficult to diagnose accurately and to distinguish from T1 colorectal carcinoma on magnifying endoscopy. Physicians should consider PG as a differential diagnosis in similar cases.

Rats do not consider all unfamiliar strains to be equivalent.

Humans show distinct social behaviours when we recognise social similarity in opponents that are members of the same social group. However, little attention has been paid to the role of social similarity in non-human animals. In the Wistar subject rats, the presence of an unfamiliar Wistar rat mitigated stress responses, suggesting the importance of social similarity in this stress-buffering phenomenon. We subsequently found that the presence of unfamiliar Sprague-Dawley (SD) or Long-Evans (LE) rats, but not an unfamiliar Fischer 344 (F344) rat, similarly mitigated stress responses in the subject rats. It is therefore possible that the subject rats recognised social similarity to unfamiliar SD and LE rats. In this study, we demonstrated that the Wistar subject rats were capable of categorizing unfamiliar rats based on their strain, and that the Wistar subjects showed a preference for unfamiliar Wistar, SD, and LE rats over F344 rats. However, the subject rats did not show a preference among Wistar, SD, and LE rats. In addition, the results were not due to an aversion to F344 rats, and preference was not affected when anaesthetised rats were presented to the subject rats. The findings suggested that rats recognise social similarity to certain unfamiliar strains of rats.

Step-clipping method can improve the detectability of the target lesion in colonic diverticular bleeding.

Background and study aims Despite the information regarding extravasation from contrast-enhanced computed tomography (CECT), the detectability of the target diverticulum by colonoscopy remains unsatisfactory in colonic diverticular bleeding (CDB). The lack of common signs recognizable on CT and endoscopic images makes it difficult to set a region of interest; however, this can be overcome with the "step-clipping" method, a strategic marking technique for revealing the target. We aimed to investigate the clinical performance of the step-clipping method in patients with CDB. Patients and methods Eighty-seven patients diagnosed with CDB with extravasation using CECT who underwent colonoscopy between August 2007 and February 2020 were included. Patients were divided into two categories: the traditional group (those who underwent colonoscopy from August 2007 to May 2017, n = 54) and the step-clipping group (those who underwent colonoscopy from June 2017 to February 2020, n = 33). Results The detection rate for the responsible diverticulum was significantly higher in the step-clipping group than in the traditional group (94 % vs 63 %; P  = .0013). The step-clipping group had a shorter average search time during colonoscopy (9.6 vs 40.5 minutes; P  < .0001) and lower re-bleeding rate after the initial colonoscopy (6 % vs 26 %; P  = .02) than the traditional group, which facilitated earlier hospital discharge (5.4 vs 6.8 days; P  = .027). Conclusions Colonoscopy using the step-clipping method can improve the detectability of the target lesion within a shorter time, thus leading to lower re-bleeding rates and earlier hospital discharge.

Estrogen increases KISS1 expression in newly generated immortalized KISS1-expressing cell line derived from goat preoptic area.

Kisspeptin neurons located in the hypothalamic preoptic area (POA) are suggested to be responsible for the induction of the gonadotropin-releasing hormone (GnRH) surge and the following luteinizing hormone (LH) surge to regulate female mammals' ovulation. Accumulating evidence demonstrates that the preovulatory level of estrogen activates the POA kisspeptin neurons (estrogen positive feedback), which in turn induces a GnRH/LH surge. This study aimed to derive a cell line from goat POA kisspeptin neurons as an in vitro model to analyze the estrogen positive feedback mechanism in ruminants. Neuron-derived cell clones obtained by the immortalization of POA tissue from a female Shiba goat fetus were analyzed for the expression of kisspeptin (KISS1) and estrogen receptor α (ESR1) genes using quantitative real-time reverse transcription-polymerase chain reaction and three cell clones were selected as POA kisspeptin neuron cell line candidates. One cell line (GP64) out of the three clones showed significant increase in the KISS1 level by incubation with estradiol for 24 h, indicating that the GP64 cells mimic endogenous goat POA kisspeptin neurons. The GP64 cells showed immunoreactivities for kisspeptin and estrogen receptor α and retained a stable growth rate throughout three passages. Further, intracellular calcium levels in the GP64 cells were increased by the KCl challenge, indicating their neurosecretory ability. In conclusion, we generated a new KISS1-expressing cell line derived from goat POA. The current GP64 cell line could be a useful model to elucidate the estrogen positive feedback mechanism responsible for the GnRH/LH surge generation in ruminants.

Existence of wild brown rats (Rattus norvegicus) that are indifferent to novel objects.

Exposure to novel objects typically evokes avoidance behavior in wild animals, which is called neophobia. We previously found that wild brown rats (Rattus norvegicus) that were trapped in a park in downtown Tokyo, Japan, exhibited neophobia. We also found that this behavior was accompanied by the activation of the basolateral complex of the amygdala (BLA). Previous studies have suggested that genetic factors are the primary determinants of neophobia. Since rats in cities form populations with distinct genetic characteristics, it is reasonable to assume that wild rats caught at different locations in urban centers will exhibit different levels of neophobia. Here we assessed the intensity of neophobia in wild rats trapped at a wholesale market in Tokyo. Although we performed exactly the same experiment in which neophobia was observed in wild rats trapped at the park, the presence of novel objects did not affect the behaviors of wild rats trapped at the market. Conversely, laboratory rats showed approach and exploratory behaviors as seen in the previous study, suggesting that the experiment was performed appropriately. Compared to the laboratory rats, the lack of behavioral changes in the wild rats was accompanied by fewer Fos immunoreactive cells in the BLA. In addition, the numbers of Fos immunoreactive cells in the bed nucleus of the stria terminalis and ventromedial hypothalamus were similar between the two types of rats. The results demonstrated the existence of wild rats that were indifferent to novel objects.

Establishment of immortalised cell lines derived from female Shiba goat KNDy and GnRH neurones.

Kisspeptin plays a critical role in governing gonadotrophin-releasing hormone (GnRH)/gonadotrophin secretion and subsequent reproductive function in mammals. The hypothalamic arcuate nucleus (ARC) kisspeptin neurones, which co-express neurokinin B (NKB) and dynorphin A (Dyn) and are referred to as KNDy neurones, are considered to be involved in GnRH generation. The present study aimed to establish cell lines derived from goat KNDy and GnRH neurones. Primary-cultured cells of female Shiba goat foetal hypothalamic ARC and preoptic area (POA) tissues were immortalised with the infection of lentivirus containing the simian virus 40 large T-antigen gene. Clones of the immortalised cells were selected by the gene expression of a neuronal marker, and then the neurone-derived cell clones were further selected by the gene expression of KNDy or GnRH neurone markers. As a result, we obtained a KNDy neurone cell line (GA28) from the ARC, as well as two GnRH neurone cell lines (GP11 and GP31) from the POA. Immunocytochemistry revealed the expression of kisspeptin, NKB and Dyn in GA28 cells, as well as GnRH in GP11 and GP31 cells. GnRH secretion from GP11 and GP31 cells into the media was confirmed by an enzyme immunoassay. Moreover, kisspeptin challenge increased intracellular Ca2+ levels in subsets of both GP11 and GP31 cells. Kisspeptin mRNA expression in GA28 cells, which expressed the oestrogen receptor alpha gene, was significantly reduced by 17ß-oestradiol treatment. Furthermore, the transcriptional core promoter and repressive regions of the goat NKB gene were detected using GA28 cells. In conclusion, we have established goat KNDy and GnRH neurone cell lines that could be used to analyse molecular and cellular mechanisms regulating KNDy and GnRH neurones in vitro, facilitating the clarification of reproductive neuroendocrine mechanisms in ruminants.

Prevalence of 17 feline behavioral problems and relevant factors of each behavior in Japan.

Undesirable behaviors exhibited by cats are regarded as feline behavioral problems. Like canine behavioral problems, feline behavioral problems are commonly reported by owners. Thus, in order to advise cat owners appropriately, veterinarians, particularly general veterinary practitioners, are encouraged to have sufficient knowledge of these problems. However, in ordinary Japanese homes, only a small number of feline behavioral problems have been investigated in terms of prevalence and relevant factors. Comprehensive survey data may improve understanding of feline behavioral problems. In the present study, we distributed an online survey including general information and questions about 17 feline behaviors which can be problematic for owners, to investigate: (1) the prevalence of feline behavioral problems, (2) the most common behavioral problems, and (3) relevant factors for each behavior. We collected 1,376 valid responses. Among all cats, 75.7% exhibited at least one behavioral problem. "Pica" and "Showing fear while on the examination table" were the most frequently reported behavioral problems. To identify factors related to the expression of each behavior, we conducted multiple logistic regression analyses, with the presence of behaviors as objective variables and cats' general information as explanatory variables. Age, sex, breed, number of cats in the household, and type of residence were each associated with more than one behavior. The present study revealed the prevalence of 17 feline behavioral problems in Japanese homes and relevant factors of each behavior. These findings will help veterinarians understand and address feline behavioral problems.

Social buffering enhances extinction of conditioned fear responses by reducing corticosterone levels in male rats.

The presence of an affiliative conspecific reduces stress responses to a wide variety of stimuli, which is termed "social buffering." We previously reported that social buffering in male rats ameliorated behavioral responses, as well as hypothalamic-pituitary-adrenal axis activation, elicited by an auditory conditioned stimulus (CS). In addition, subjects that experienced social buffering did not show stress responses when re-exposed to the CS the next day in the absence of an accompanying rat. However, the mechanisms underlying this enhancement of between-session extinction are poorly understood. In Experiment 1, we compared corticosterone levels at 0, 10, and 15 min after extinction training. Subjects that experienced social buffering had lower corticosterone levels than subjects that trained alone at the end of extinction training. However, corticosterone levels at 10 and 15 min after training were not affected by the experience of social buffering. These results suggest that a lower level of corticosterone during extinction training had an important role in the enhancement of extinction. To directly assess this, in Experiment 2, we manipulated the corticosterone level during extinction training. We found that a subcutaneous injection of corticosterone before extinction training blocked the enhancement of extinction by social buffering. These results demonstrate that the enhancement is caused by a low level of corticosterone during the training. Taken together, we suggest that social buffering enhances extinction of conditioned fear responses by reducing corticosterone levels in male rats.

Novel objects elicit greater activation in the basolateral complex of the amygdala of wild rats compared with laboratory rats.

Wild animals tend to avoid novel objects that do not elicit clear avoidance behaviors in domesticated animals. We previously found that the basolateral complex of the amygdala (BLA) and dorsal bed nucleus of the stria terminalis (dBNST) were larger in trapped wild rats compared with laboratory rats. Based on these findings, we hypothesized that the BLA and/or dBNST would be differentially activated when wild and laboratory rats showed different avoidance behaviors towards novel objects. In this study, we placed novel objects at one end of the home cage. We measured the time spent in that half of the cage and expressed the data as a percentage of the time spent in that region with no object placement. We found that this percentage was lower in the wild rats compared with the laboratory rats. These behavioral differences were accompanied by increased Fos expression in the BLA, but not in the dBNST, of the wild rats. These results suggest that wild rats show greater BLA activation compared with laboratory rats in response to novel objects. We also found increased Fos expression in the paraventricular nucleus of the hypothalamus, ventral BNST, and ventromedial hypothalamus, but not in the central amygdala of wild rats. Taken together, our data represent new information regarding differences in behavioral and neural responses towards novel objects in wild vs. laboratory rats.

The lateral intercalated cell mass of the amygdala is activated during social buffering of conditioned fear responses in male rats.

The presence of an affiliative conspecific reduces stress responses to a wide variety of stimuli. This phenomenon is termed "social buffering". We previously found that the presence of another Wistar rat (associate) suppressed activation of the lateral amygdala (LA) and ameliorated stress responses to an auditory conditioned stimulus (CS) in a fear-conditioned Wistar subject rat. Subsequent analyses suggested that activation of the posterior complex of the anterior olfactory nucleus (AOP) is responsible for the suppression of the LA. However, it remains unclear how the AOP suppresses the LA. To clarify this issue, a fear-conditioned Wistar subject was exposed to the CS either alone or with a Wistar associate. We also prepared a fear-conditioned Wistar subject that was tested with a Fischer344 (F344) associate as an additional control because F344 associates do not induce social buffering. We found that the presence of a Wistar associate induced a reduction of behavioral responses and Fos expression in the paraventricular nucleus of the hypothalamus (PVN) of the subject. Although Fos expression in the AOP was increased, the expression was not biased towards the GABAergic cells. In addition, Fos expression in the lateral intercalated cell mass of the amygdala (lITC) was increased. In contrast, the presence of a F344 associate did not affect Fos expression in subjects' PVN or lITC, whereas behavioral responses were slightly reduced. These results suggest that the lITC was activated during social buffering. Based on these findings, we propose that the AOP indirectly suppresses the LA by activating the lITC.

Prevalence of 25 canine behavioral problems and relevant factors of each behavior in Japan.

Undesirable behaviors exhibited by dogs are called canine behavioral problems. Behavioral problems are common among dogs kept in ordinary homes; hence, veterinarians need to have sufficient knowledge of these problems, so as to advise owners. Among dogs kept in ordinary Japanese homes, only a few behaviors have been investigated regarding prevalence and relevant factors. To improve understanding of behavioral problems, a comprehensive survey is crucial. In this study, we distributed an online survey including general information and questions about 25 canine behaviors that can become problematic to owners, to investigate (1) the prevalence of behavioral problem, (2) the most common behavioral problems, and (3) the relevant factors of each behavior. We collected 2,050 valid responses. Among all dogs, 86.0% exhibited at least one behavioral problem. "Barking at noises inside the house", "Barking at unfamiliar visitors", and "Pica" were the most frequent behavioral problems. To reveal those factors related to the expression of each behavior, we performed multiple logistic regression analyses, with the presence of behaviors as objective variables and dogs' general information as explanatory variables. Breed, age, the presence of other dogs in the household, sex, neutering status, source of acquisition, and type of residence were associated with 19, 16, 5, 4, 4, 4, and 1 behaviors, respectively. This study revealed the prevalence of 25 canine behavioral problems in Japan and relevant factors of each behavior. Our findings will be useful for veterinarians in advising owners about preventing behavioral problems.