Opposing roles for D-1 and D-2 dopamine receptors in regulating the excitability of growth hormone-producing cells in the snail Lymnaea stagnalis.
Dopamine hyperpolarizes growth hormone-producing cells (GHC) in the CNS of Lymnaea stagnalis. This effect of dopamine was mimicked by the D-2 receptor agonist LY 141865 and antagonized by the D-2 receptor antagonists (-)-sulpiride and YM 09151-2. SKF 38393, a selective D-1 receptor agonist, increased the excitability of the GHC. This effect was mimicked by intracellular injection of cyclic AMP and antagonized by the D-1 receptor antagonist SCH 23390. Dopamine (in the presence of (-)-sulpiride) also increased the excitability of the GHC. It is concluded that both a D-1 and a D-2 receptor regulate the electrical activity of the GHC in the CNS of Lymnaea stagnalis.
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002490:Central Nervous System / Q000378:metabolism; D000242:Cyclic AMP / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004594:Electrophysiology; D004873:Ergolines / Q000494:pharmacology; D006133:Growth Substances / Q000096:biosynthesis*; D066298:In Vitro Techniques; D007447:Invertebrate Hormones / Q000096:biosynthesis*; D008195:Lymnaea / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D019257:Quinpirole; D011954:Receptors, Dopamine / Q000502:physiology*; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013469:Sulpiride / Q000494:pharmacology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
D004873:Ergolines; D006133:Growth Substances; D007447:Invertebrate Hormones; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013764:Tetrahydronaphthalenes; C021690:growth hormone, Lymnaea stagnalis; D019257:Quinpirole; D003994:Bucladesine; C037253:2-(N,N-dipropyl)amino-6,7-dihydroxytetralin; D013469:Sulpiride; D000242:Cyclic AMP; D004298:Dopamine