Dopamine D2 receptor effects on GABA(A) receptor expression may modify melanotrope peptide release.
Stimulation of melanotrope dopamine D2 receptors decreases mitotic rate, calcium channel activity, and the biosynthesis of several proteins. This study demonstrates that D2 receptor activation also affects GABA(A) receptor beta2/beta3 subunit immunoreactivity. Following chronic treatment with haloperidol, a D2 receptor antagonist, GABA(A) receptor immunoreactivity increased, whereas it decreased after chronic treatment with bromocriptine, a dopamine D2 receptor agonist. Thus, these data indicate that D2 function regulates GABA(A) receptor expression in melanotropes, a mechanism by which peptide release may be modified.
Sands
S A
SA
School of Biological Sciences, University of Missouri-Kansas City, 64110, USA.
de Blas
A L
AL
Chronwall
B M
BM
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D006220:Haloperidol / Q000494:pharmacology; D007150:Immunohistochemistry; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D010902:Pituitary Gland / Q000187:drug effects / Q000502:physiology; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000502:physiology*; D011963:Receptors, GABA-A / Q000502:physiology*
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D017448:Receptors, Dopamine D2; D011963:Receptors, GABA-A; D001971:Bromocriptine; D011333:Pro-Opiomelanocortin; D009074:Melanocyte-Stimulating Hormones; D006220:Haloperidol