Stimulation of @entity935 D2 receptors inhibits melanotrope @entity9210 ( @entity9210 ) biosynthesis and @entity9210 (MSH) secretion. These effects are mediated by G-protein alpha i- and alpha o-subunits and are reversed by stimulating receptors linked to activation of G alpha s protein. Melanotrope activity is increased by @entity1767 , a D2 receptor antagonist, and decreased by @entity2847 , a D2 receptor agonist. Both the short and long isoforms of the D2 receptor mRNA and protein increase following chronic @entity1767 treatment. After chronic @entity2847 treatment the short isoform is downregulated, whereas the long isoform is upregulated. Our hypothesis is that specific G protein alpha- subunits alter in pattern of expression similarly to the receptor isoforms. Using immunohistochemistry and in situ hybridization, this study examined changes in G alpha i, G alpha o, and G alpha s protein and mRNA expression following chronic treatments with @entity2847 or @entity1767 . G alpha i3 and G alpha o immunoreactivities increased following @entity2847 treatment, whereas G alpha s and @entity22684 did not change. Gs immunoreactivity increased after @entity1767 treatment, whereas G alpha @entity40266 o did not change. G alpha i and G alpha o mRNA increased following @entity2847 and decreased following @entity1767 treatments, whereas the inverse results were observed with G alpha s mRNA. These results suggest D2 receptor activation can specifically increase G alpha i3 and G alpha o expression, and D2 receptor blockade increases G alpha s expression.

XXXX D2 receptor stimulation alters G-protein expression in rat pituitary intermediate lobe melanotropes.

@entity2847 :: ('MESH:D001971', 'Chemical') :: ['bromocriptine'] @entity40266 :: ('58977(Tax:10116)', 'Gene') :: ['i1/2, G alpha i3, and G alpha'] @entity9210 :: ('24664(Tax:10116)', 'Gene') :: ['alpha-melanocyte-stimulating hormone', 'pro-opiomelanocortin', 'POMC'] @entity935 :: ('MESH:D004298', 'Chemical') :: ['dopamine'] @entity22684 :: ('81664(Tax:10116)', 'Gene') :: ['G alpha i1/2'] @entity1767 :: ('MESH:D006220', 'Chemical') :: ['haloperidol']
@entity935 :: (MESH:D004298,Chemical) :: ['Dopamine']
