Dopamine receptor stimulation induces a potassium dependent hyperpolarizing response in growth hormone producing neuroendocrine cells of the gastropod mollusc Lymnaea stagnalis.
Of several putative transmitters used, dopamine was the only one which caused (at low concentrations) a hyperpolarizing response (H-response) in growth hormone producing cells (GHCs) of the freshwater snail Lymnaea stagnalis. Membrane resistance changes, and shifts in the reversal potential of this H-response in different K+-concentrations, indicate that the response is due to an increase in potassium conductance. The dopamine induced H-response is blocked by (-)-sulpiride, 4-aminopyridine, dibutyryl cAMP, 8CPT-cAMP, forskolin and IBMX. These data suggest that dopamine induces the H-response by stimulating a receptor resembling the mammalian D-2 receptor and that this effect of dopamine is mediated by a decrease in the formation of intracellular cAMP.
de Vlieger
T A
TA
Lodder
J C
JC
Stoof
J C
JC
Werkman
T R
TR
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001679:Biogenic Amines / Q000494:pharmacology; D004702:Endocrine Glands / Q000502:physiology; D013006:Growth Hormone / Q000096:biosynthesis*; D066298:In Vitro Techniques; D007478:Iontophoresis; D008195:Lymnaea / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D009424:Nervous System Physiological Phenomena; D009469:Neuromuscular Junction / Q000187:drug effects; D018377:Neurotransmitter Agents / Q000502:physiology; D011188:Potassium / Q000502:physiology*; D011954:Receptors, Dopamine / Q000187:drug effects*
D001679:Biogenic Amines; D018377:Neurotransmitter Agents; D011954:Receptors, Dopamine; D013006:Growth Hormone; D000262:Adenylyl Cyclases; D011188:Potassium