Muscarine affects calcium-currents in rat hippocampal pyramidal cells in vitro.
Ca2+-currents were recorded from single CA3 pyramidal cells in hippocampal slice cultures, voltage-clamped through a single Cs+ - or K+-filled microelectrode and perfused with Hanks' balanced salt solution containing 1 microM tetrodotoxin and 10 mM tetraethylammonium. The Ca2+-current was reversibly reduced by bath-perfused muscarine (10-100 microM). This effect was inhibited by pirenzepine (10 microM) or atropine (1 microM). In K+-filled cells, inhibition was preceded by a phase of inward current enhancement; this was considered to be secondary to rapid outward current inhibition induced it by muscarine since it was reduced when outward currents were previously inhibited with Ba2+. In partially clamped or unclamped cells inhibition of Ca2+-current leads to a shortening of the Ca2+-spike plateau.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D004553:Electric Conductivity; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009116:Muscarine / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects; D010890:Pirenzepine / Q000494:pharmacology; D051381:Rats; D014403:Tubocurarine / Q000494:pharmacology
D010890:Pirenzepine; D001285:Atropine; D009116:Muscarine; D002118:Calcium; D014403:Tubocurarine