title: Effects of alpha-MSH, TRH and AVP on learning and memory, pain threshold, and motor activity: preliminary results.
abstract: The effect of daily peripheral administration of various peptides on learning and memory performance was studied in male albino rats. Groups of rats were treated with either TRH (1.0 mg/kg) alpha-MSH (1.0 mg/kg), or saline for three days. Other groups were treated either with vasopressin (1.0 microgram/kg) or saline. All treatments were 30 min before testing in a Morris Water Task apparatus. This type of learning is spatial learning which requires integration of environmental cues. Only alpha-MSH treated rats exhibited improved learning on Day 1 and Day 3 of the training period. One month later all rats were retested with no difference between the experimental groups. Single doses of these peptides caused a nonsignificant increase in pain threshold. The body weight gain of vasopressin-treated rats was significantly reduced as well as their motoric behavior. Therefore, the alpha-MSH effect on learning cannot be explained by nonspecific effects on body weight, pain threshold, or motor activity level.
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects; D007858:Learning / Q000187:drug effects*; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D008568:Memory / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects*; D010146:Pain / Q000188:drug therapy*; D051381:Rats; D011919:Rats, Inbred Strains; D013028:Space Perception / Q000187:drug effects; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
chemical_list: D001127:Arginine Vasopressin; D013973:Thyrotropin-Releasing Hormone; D009074:Melanocyte-Stimulating Hormones