Effects of thyrotropin-releasing hormone (TRH) and MK-771 on schedule-controlled behavior of squirrel monkeys, rabbits and pigeons.
The effects of TRH (0.001-10.0 mg/kg) and a more potent TRH analog, MK-771 (0.001-5.6 mg/kg), were studied on comparable schedule-controlled performances of squirrel monkeys, rabbits and pigeons. Responding was maintained in the presence of different stimuli by a multiple fixed-ratio (FR), fixed-interval (FI) schedule of food presentation (monkeys and pigeons) or 0.25% saccharin solution (rabbits). Generally, TRH and MK-771 produced decreases in responding under both schedules and in all three species. TRH and MK-771 were roughly equipotent in the squirrel monkey, whereas in the pigeon and rabbit MK-771 was approximately 20 times more potent than TRH in decreasing responding to 50 percent of control levels. The duration of action of doses of TRH and MK-771 that reduced responding to 50 percent of control was approximately 3 hr in the squirrel monkey; recovery of performance occurred twice as fast under the FR schedules. With the pigeon, TRH effects that produced 50 percent decreases in responding lasted over 6 hours, whereas behaviorally comparable doses of MK-771 lasted about 4 hours. With few exceptions, TRH and MK-771 appear to produce similar effects of schedule-controlled behavioral performances of the squirrel monkey, rabbit and pigeon. Compared to the effects of other behaviorally-active substances under these procedures, TRH and MK-771 exert a distinctive array of effects.
D000818:Animals; D010856:Columbidae; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D007273:Injections, Intramuscular; D008297:Male; D011817:Rabbits; D012055:Reinforcement Schedule; D012453:Saimiri; D013045:Species Specificity; D053778:Thiazolidines; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*
D053778:Thiazolidines; D013973:Thyrotropin-Releasing Hormone; C021597:pyro(l-alpha-aminoadipyl)-L-histidyl-L-thiazolidine-4-carboxamide