Effects of thyrotropin-releasing hormone (TRH) and a TRH analogue, MK-771, on punished responding of squirrel monkeys.

The effects of thyrotropin-releasing hormone (TRH) and an enzyme-resistant analogue, MK-771, were compared on punished responding of squirrel monkeys maintained either by food presentation or stimulus-shock termination. Both TRH and MK-771 (1.0-30 mg/kg IM) produced dose-related decreases in punished responding maintained by food presentation and dose-related increases in punished responding maintained by shock termination. TRH was more potent than MK-771 in altering punished response rates maintained by either event.