Opposite effects of gamma(1)- and gamma(2)-melanocyte stimulating hormone on regulation of the dopaminergic mesolimbic system in rats.
By use of the brain microdialysis technique we show that administration of gamma(1)-melanocyte stimulating hormone (gamma(1)-MSH) into the ventral tegmental area of anaesthetized rats causes an increase in the release of extracellular dopamine and its metabolite 3,4-dihydroxyphenylacetic acid in the nucleus accumbens, while gamma(2)-MSH causes the opposite effect. Moreover, gamma(2)-MSH pre-treatment considerably reduced the gamma(1)-MSH-induced effects. Our findings suggest an opposing action of two gamma-MSH-activated pathways on the mesolimbic dopaminergic system, which could be important in the maintenance of a balanced psychoactivation state.
Jansone
Baiba
B
Department of Pharmacology, Faculty of Medicine, University of Latvia, 1A Sarlotes Street, LV-1001 Riga, Latvia.
Bergstrom
Lena
L
Svirskis
Simons
S
Lindblom
Jonas
J
Klusa
Vija
V
Wikberg
Jarl E S
JE
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology; D004298:Dopamine / Q000378:metabolism*; D008032:Limbic System / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009434:Neural Pathways / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D017557:Ventral Tegmental Area / Q000187:drug effects* / Q000378:metabolism; D019825:gamma-MSH / Q000378:metabolism / Q000494:pharmacology*
D019825:gamma-MSH; D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine