Behavioural responses of gamma-MSH peptides administered into the rat ventral tegmental area.
The behavioural effects induced by alpha-, gamma1- and gamma2-MSH peptides (0.3 and 3 nmole per rat) injected into the left ventral tegmental area (VTA) of rats were compared. alpha- and gamma1-MSH caused grooming of comparable magnitude, and also additional vertical activity (rearing). By contrast gamma2-MSH caused a moderate but stable catalepsy, and practically no grooming. Moreover, intra-VTA pre-treatment with gamma2-MSH, 15 min prior to intra-VTA gamma1-MSH, markedly attenuated both the gamma1-induced grooming and vertical activities. The differences in the behavioural response of the MSH peptides indicate that they act differentially on MC receptors in the VTA.
Klusa
V
V
Laboratory of Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia.
Svirskis
S
S
Opmane
B
B
Muceniece
R
R
Wikberg
J E
JE
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D002375:Catalepsy / Q000139:chemically induced; D006120:Grooming / Q000502:physiology; D008297:Male; D008845:Microinjections; D009043:Motor Activity / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D017557:Ventral Tegmental Area / Q000187:drug effects*; D019825:gamma-MSH / Q000494:pharmacology*
D019825:gamma-MSH