Glycolytic ATP Production Regulates Muscarinic Cation Currents in Guinea-pig Ileum

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We investigated the possible sources of intracellular ATP which was previously shown essential for maintaining the muscarinic cationic channel activities (or currents; I_<cat>) in guinea-pig ileal myocytes, using two variants of patch clamp techniques. Deprivation of external glucose or its replacement with 2-deoxyglucose significantly reduced the magnitude of I_<cat> recorded with nystatin-perforated method, with greater efficacy than for voltage-dependent Ca^<2+> current. Intracellular dialysis of ileal myocytes with key substrates for glycolysis, oxidative metabolism and creatine-phosphocreatine system all resulted in a comparably effective maintenance of I_<cat>, which was abolished by inhibitors for these ATP-producing systems, 3-bromopyruvate, cyanide and 2,4-dinitrofluorobenzene (DNFB), respectively. However, amongst these inhibitors, only 3-bromopyruvate effectively reduced I_<cat> recorded with the nystatin-perforated method. These results strongly suggest the exclusive physiological importance of glycolytic ATP production in maintaining I_<cat> activity, and thus this mechanism may play a role in the regulation of gut motility.
日本平滑筋学会の論文