Body pinch induces long lasting cataleptic like immobility in mice: Behavioral characterization and the effect of naloxone

The present article reports that repeated exposure to brief pinches at the scruff in mice results in the development of long lasting cataleptic-like immobility. The response is robust, readily induced and involves changes in autonomic functions and pain sensitivity. The development of catalepsy and the concominant antinociception are blocked by naloxone pretreatment. In contrast, naloxone fails to suppress the pinch-induced catalepsy when administered after this behavior has already been established. Taken together, the findings offer a simple and most reliable model to study the neural mechanisms that mediate “naturally occurring”, stress- induced catalepsy.