Effects of dopamine on the release of thyrotropin-releasing hormone from the rat retina in vitro.
The effects of dopamine on the release of thyrotropin-releasing hormone (TRH) from the rat retina in vitro were studied. The rat retina was incubated in the medium 199 (pH 7.4) with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid. The amount of TRH release into the medium was measured by radioimmunoassay. The TRH release from the rat retina was inhibited significantly in a dose-related manner with the addition of dopamine, but not with pimozide. The inhibitory effects of dopamine on TRH release from the rat retina were blocked with an addition of pimozide to the medium. The elution profile of methanol-extracted rat retina on sephadex G-10 was identical to that of synthetic TRH. From these findings it is concluded that the dopaminergic system inhibits TRH release from the rat retina in vitro.
Mitsuma
T
T
Fourth Department of Internal Medicine, Aichi Medical University, Japan.
Hirooka
Y
Y
Izeki
K
K
Sin
K
K
Nogimori
T
T
D000704:Analysis of Variance; D000818:Animals; D004298:Dopamine / Q000494:pharmacology*; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D010868:Pimozide / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000187:drug effects* / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism*
D018492:Dopamine Antagonists; D010868:Pimozide; D013973:Thyrotropin-Releasing Hormone; D004298:Dopamine