The effects of anxiolytics and other agents on rat grooming behavior.

BN and other peptides increase grooming activity in rodents. This increase in grooming activity caused by BN can be reversed by numerous agents. The most direct of these are BN receptor antagonists such as spantide and [D-Phe-12]BN. These agents reverse the increase in grooming activity caused by BN and inhibit binding to central BN receptors. The increase in grooming activity caused by BN may be mediated by other neurotransmitters, such as dopamine. In this regard the increase in grooming activity caused by BN is reversed by fluphenazine and haloperidol. These agents do not affect binding to central BN receptors. Similarly, the increase in grooming caused by BN is absent if dopamine-containing neurons are lesioned with 6-OHDA. These lesions cause a significant reduction in central BN receptors, especially in the central amygdaloid nucleus. Thus some of the BN receptors may be present on dopamine-containing neurons. The increase in grooming activity caused by BN was also reversed by diazepam and chlordiazepoxide. Neither of these agents affected binding to central BN receptors, and similarly, BN did not affect binding to central benzodiazepine receptors. Thus anxiolytics may act at a site anatomically downstream from the BN receptor and reduce the apparent stress caused by central injection of BN.