A single exposure to the predator odor 2,4,5-trimethylthiazoline causes long-lasting affective behavioral changes in female mice: Modulation by kappa opioid receptor signaling
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引用次数: 0
Abstract
The volatile compound 2,4,5-trimethylthiazoline (TMT, a synthetic predator scent) triggers fear, anxiety, and defensive responses in rodents that can outlast the encounter. The receptor systems underlying the development and persistence of TMT-induced behavioral changes remain poorly characterized, especially in females. Kappa opioid receptors regulate threat generalization and fear conditioning and alter basal anxiety, but their role in unconditioned fear responses in females has not been examined. Here, we investigated the effects of the long-lasting kappa opioid receptor antagonist, nor-binalthorphinmine dihydrochloride (nor-BNI; 10 mg/kg), on TMT-induced freezing and conditioned place aversion in female mice. We also measured anxiety-like behavior in the elevated plus maze three days after TMT and freezing behavior when returned to the TMT-paired context ten days after the single exposure. We found that 35 of 10 % TMT elicited a robust freezing response during a five-minute exposure in female mice. TMT evoked persistent fear as measured by conditioned place aversion, reduced entries into the open arm of the elevated plus maze, and increased general freezing behavior long after TMT exposure. In line with the known role of kappa-opioid receptors in threat generalization, we found that kappa-opioid receptor antagonism increased basal freezing but reduced freezing during TMT presentation. Together, these findings indicate that a single exposure to TMT causes long-lasting changes in fear-related behavioral responses in female mice and highlights the modulatory role of kappa-opioid receptor signaling on fear-related behavioral patterns in females.
期刊介绍:
Pharmacology Biochemistry & Behavior publishes original reports in the areas of pharmacology and biochemistry in which the primary emphasis and theoretical context are behavioral. Contributions may involve clinical, preclinical, or basic research. Purely biochemical or toxicology studies will not be published. Papers describing the behavioral effects of novel drugs in models of psychiatric, neurological and cognitive disorders, and central pain must include a positive control unless the paper is on a disease where such a drug is not available yet. Papers focusing on physiological processes (e.g., peripheral pain mechanisms, body temperature regulation, seizure activity) are not accepted as we would like to retain the focus of Pharmacology Biochemistry & Behavior on behavior and its interaction with the biochemistry and neurochemistry of the central nervous system. Papers describing the effects of plant materials are generally not considered, unless the active ingredients are studied, the extraction method is well described, the doses tested are known, and clear and definite experimental evidence on the mechanism of action of the active ingredients is provided.