Acetylcholine (Ach) was tested for its effect on calcium currents in primary cultures of embryonic rat hippocampal neurones. 10 μM Ach reversibly depressed the high voltage activated (HVA) Ca current and the effect was blocked by atropine. When GTP binding proteins (G-proteins) were irreversibly activated by intracellularly perfusing the neurons with GTP[ S], one short-lasting application of Ach permanently inhibited Ca currents. Alternatively, the transmitter was inactive when the cells were preincubated with pertussis toxin, which inactivates some G-proteins by catalyzing ADP ribosylation. Our results suggest that a G-protein mediates the inhibitory modulation of the HVA Ca current by muscarinic agonists.
Ca channels Acetylcholine G-proteins Hippocampus
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Gähwiler BH, Brown DA (1987) Muscarine affects calcium currents in rat hippocampal piramidal cells in vitro. Neurosci Lett 76:301–306CrossRefPubMedGoogle Scholar
Misgeld U, Calabresi P, Dodt U (1986) Muscarinic modulation of calcium dependent plateau potentials in rat neostriatal neurons. Pflüger Arch 407:482–487CrossRefGoogle Scholar
Wanke E, Ferroni A, Malgaroli A, Ambrosini A, Pozzan T, Meldolesi J (1987) Activation of muscarinic receptor selectively inhibits a rapidly inactivated Ca current in rat sympathetic neurons. Proc Natl Acad Sci USA 84:4313–4317CrossRefPubMedPubMedCentralGoogle Scholar
Yaari Y, Hamon B, Lux HD (1987) Development of two types of calcium channels in cultured mammalian hippocampal neurons. Science 235:680–682CrossRefPubMedGoogle Scholar