Effects of protein kinase C on the muscarinic excitation of rat adrenal chromaffin cells.
The role of protein kinase C (PKC) in the muscarinic excitation of chromaffin cells freshly isolated from rat adrenal medullae was examined by the patch-clamp recording method. Acetylcholine and McN-A-343, a M1-receptor agonist, depolarized the cell and induced action potentials. Phorbol 12,13-dibutyrate (PDBu), an activator of PKC, increased acetylcholine-induced firing concomitant with a persistent depolarization. Under voltage-clamp recording, both McN-A-343 and PDBu decreased the cesium-sensitive K+ current, which was induced by shifting the membrane potential between -140 mV and -40 mV. These results suggested that the stimulation of muscarinic M1-receptors by cholinergic drugs activated phospholipase C to degrade phosphoinositide, consequently producing diacylglycerol, and diacylglycerol activates PKC to induce excitation of adrenal chromaffin cells.
Akaike
A
A
Department of Neuropharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Japan.
Sasa
M
M
Tamura
Y
Y
Ujihara
H
H
Takaori
S
S
D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000313:Adrenal Medulla / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D004759:Enterochromaffin Cells / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D008839:Microelectrodes; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects; D011493:Protein Kinase C / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000187:drug effects*
D015221:Potassium Channels; D011976:Receptors, Muscarinic; D015240:Phorbol 12,13-Dibutyrate; D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride; D011493:Protein Kinase C; D000109:Acetylcholine