Project description:Behavioral transitions Young infant rats paradoxically prefer odors paired with shock but older pups learn aversions. This transition is amygdala- and corticosterone-dependent. Microarray results showed downregulated dopaminergic presynaptic function in the amygdala with preference learning. Corticosterone injected 8-day-old pups and untreated 12-day-old pups learn aversions and had dopaminergic upregulation in the amygdala.
Project description:Behavioral transitions Young infant rats paradoxically prefer odors paired with shock but older pups learn aversions. This transition is amygdala- and corticosterone-dependent. Microarray results showed downregulated dopaminergic presynaptic function in the amygdala with preference learning. Corticosterone injected 8-day-old pups and untreated 12-day-old pups learn aversions and had dopaminergic upregulation in the amygdala. 8 day saline or corticosterone treated- or 12 day old untreated rat pups were trained with odor-shock pairings. Immediately after training pups were sacrificed and the amygdala dissected out. Controls were unpaired shock-odor groups.Paired and unpaired groups were processed together for each experimental condition. Paired and unpaired data were compared by ranked products.
Project description:We show that infant trauma, as modeled by infant paired odor-shock conditioning, results in later life depressive-like behavior that can be modulated by learned infant cues (i.e., odor previously paired with shock). We have previously shown that this infant attachment odor learning paradigm results in the creation of a new artificial maternal odor that is able to control pup behavior and retain its value throughout development. Here, we assess the mechanism by which this artificial maternal odor is able to rescue depressive-like behavior and show that this anti-depressant like effect results in glucocorticoid and serotonin (5-HT) related changes in amygdala gene expression and is dependent on amygdala 5-HT. Furthermore, increasing amygdala 5-HT and blocking corticosterone (CORT) in the absence of odor mimics the adult rescue effects elicited by the artificial maternal odor, suggesting a mechanism by which odor presentation exerts its repair effects. There are three experimental groups: 1: pups with no infant shock and the adult forced swim test (FST)with no odor; 2. pups with infant odor-shock pairing and the adult forced swim test (FST) with no odor; 3. pups with infant odor-shock pairing and adult forced swim test with infant odor.
Project description:We show that infant trauma, as modeled by infant paired odor-shock conditioning, results in later life depressive-like behavior that can be modulated by learned infant cues (i.e., odor previously paired with shock). We have previously shown that this infant attachment odor learning paradigm results in the creation of a new artificial maternal odor that is able to control pup behavior and retain its value throughout development. Here, we assess the mechanism by which this artificial maternal odor is able to rescue depressive-like behavior and show that this anti-depressant like effect results in glucocorticoid and serotonin (5-HT) related changes in amygdala gene expression and is dependent on amygdala 5-HT. Furthermore, increasing amygdala 5-HT and blocking corticosterone (CORT) in the absence of odor mimics the adult rescue effects elicited by the artificial maternal odor, suggesting a mechanism by which odor presentation exerts its repair effects.
Project description:Few studies have assessed the patterns of parasite populations of rodents over a longitudinal gradient in Chile. In this work, the gastrointestinal helminthic fauna of invasive rodents in Chile was examined to assess the association between their presence/absence and abundance with latitude, host sex, and host body condition, and to assess the coexistence and correlation of the abundance between parasite species. Rodents were obtained from 20 localities between 33 and 43°S. Helminths were extracted from the gastrointestinal tract and identified morphologically. Overall, 13 helminth taxa were obtained. The most frequently identified parasite species was Heterakis spumosa, and the most abundant was Syphacia muris, while Physaloptera sp. was the most widely distributed. No locality presented with a coexistence that was different from that expected by chance, while the abundance of five helminthic species correlated with the abundance of another in at least one locality, most likely due to co-infection rather than interaction. Host sex was associated with parasite presence or abundance, and female sex-biased parasitism was notably observed in all cases. Body condition and latitude presented either a positive or negative association with the presence or abundance of parasites depending on the species. It is notable that the likely native Physaloptera sp. is widely distributed among invasive rodents. Further, gravid females were found, suggesting spillback of this species to the native fauna. The low frequency and abundance of highly zoonotic hymenolepid species suggest that rodents are of low concern regarding gastrointestinal zoonotic helminths.
Project description:The Norway rat has important impacts on our life. They are amongst the most used research subjects, resulting in ground-breaking advances. At the same time, wild rats live in close association with us, leading to various adverse interactions. In face of this relevance, it is surprising how little is known about their natural behaviour. While recent laboratory studies revealed their complex social skills, little is known about their social behaviour in the wild. An integration of these different scientific approaches is crucial to understand their social life, which will enable us to design more valid research paradigms, develop more effective management strategies, and to provide better welfare standards. Hence, I first summarise the literature on their natural social behaviour. Second, I provide an overview of recent developments concerning their social cognition. Third, I illustrate why an integration of these areas would be beneficial to optimise our interactions with them.
Project description:BackgroundMurine kobuviruses (MuKV) are newly recognized picornaviruses first detected in murine rodents in the USA in 2011. Little information on MuKV epidemiology in murine rodents is available. Therefore, we conducted a survey of the prevalence and genomic characteristics of rat kobuvirus in Guangdong, China.ResultsFecal samples from 223 rats (Rattus norvegicus) were collected from Guangdong and kobuviruses were detected in 12.6% (28) of samples. Phylogenetic analysis based on partial 3D and complete VP1 sequence regions showed that rat kobuvirus obtained in this study were genetically closely related to those of rat/mouse kobuvirus reported in other geographical areas. Two near full-length rat kobuvirus genomes (MM33, GZ85) were acquired and phylogenetic analysis of these revealed that they shared very high nucleotide/amino acids identity with one another (95.4%/99.4%) and a sewage-derived sequence (86.9%/93.5% and 87.5%/93.7%, respectively). Comparison with original Aichivirus A strains, such human kobuvirus, revealed amino acid identity values of approximately 80%.ConclusionOur findings indicate that rat kobuvirus have distinctive genetic characteristics from other Aichivirus A viruses. Additionally, rat kobuvirus may spread via sewage.