title: Diazepam and endorphin independently inhibit ultrasonic distress calls in rats.
abstract: Ultrasonic distress calls elicited in male rats by footshock under inescapable conditions were suppressed by diazepam. The suppression was blocked by pretreatment with Ro15-1788 or CGS8216, selective benzodiazepine receptor antagonists, while an opiate antagonist naloxone failed to modify the effect of diazepam. In contrast, naloxone antagonized but Ro15-1788 and CGS8216 did not antagonize beta-endorphin which also suppressed the ultrasonic vocalization. These findings suggest that benzodiazepine and opioid receptors may contribute separately to antianxiety activity.
mesh_terms: D000818:Animals; D003292:Convulsants / Q000494:pharmacology; D003864:Depression, Chemical; D003975:Diazepam / Q000494:pharmacology*; D004723:Endorphins / Q000494:pharmacology*; D005442:Flumazenil / Q000494:pharmacology; D007279:Injections, Subcutaneous; D008297:Male; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000187:drug effects*
chemical_list: D003292:Convulsants; D004723:Endorphins; D011720:Pyrazoles; D005442:Flumazenil; C033830:2-phenylpyrazolo(4,3-c)quinolin-3(5H)-one; D003975:Diazepam