title: Carbachol regulates pacemaker activities in cultured interstitial cells of Cajal from the mouse small intestine.
abstract: We studied the effect of carbachol on pacemaker currents in cultured interstitial cells of Cajal (ICC) from the mouse small intestine by muscarinic stimulation using a whole cell patch clamp technique and Ca2+-imaging. ICC generated periodic pacemaker potentials in the current-clamp mode and generated spontaneous inward pacemaker currents at a holding potential of-70 mV. Exposure to carbachol depolarized the membrane and produced tonic inward pacemaker currents with a decrease in the frequency and amplitude of the pacemaker currents. The effects of carbachol were blocked by 1-dimethyl-4-diphenylacetoxypiperidinium, a muscarinic M(3) receptor antagonist, but not by methotramine, a muscarinic M(2) receptor antagonist. Intracellular GDP-beta-S suppressed the carbachol-induced effects. Carbachol-induced effects were blocked by external Na+-free solution and by flufenamic acid, a non-selective cation channel blocker, and in the presence of thapsigargin, a Ca2+-ATPase inhibitor in the endoplasmic reticulum. However, carbachol still produced tonic inward pacemaker currents with the removal of external Ca2+. In recording of intracellular Ca2+ concentrations using fluo 3-AM dye, carbachol increased intracellular Ca2+ concentrations with increasing of Ca2+ oscillations. These results suggest that carbachol modulates the pacemaker activity of ICC through the activation of non-selective cation channels via muscarinic M(3) receptors by a G-protein dependent intracellular Ca2+ release mechanism.
authors.affiliation: Department of Anesthesiology, College of Medicine, Chosun University, Gwangju 501-759, Korea.
authors.forename: Keum Young
authors.initials: KY
authors.lastname: So
authors.forename: Sang Hun
authors.initials: SH
authors.lastname: Kim
authors.forename: Hong Moon
authors.initials: HM
authors.lastname: Sohn
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Choi
authors.forename: Shankar Prasad
authors.initials: SP
authors.lastname: Parajuli
authors.forename: Seok
authors.initials: S
authors.lastname: Choi
authors.forename: Cheol Ho
authors.initials: CH
authors.lastname: Yeum
authors.forename: Pyung Jin
authors.initials: PJ
authors.lastname: Yoon
authors.forename: Jae Yeoul
authors.initials: JY
authors.lastname: Jun
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001683:Biological Clocks / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002217:Carbachol / Q000494:pharmacology*; D027682:Cation Transport Proteins / Q000037:antagonists & inhibitors; D002478:Cells, Cultured; D003959:Diamines / Q000494:pharmacology; D005439:Flufenamic Acid / Q000494:pharmacology; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D007421:Intestine, Small / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D010880:Piperidines / Q000494:pharmacology*; D018517:Plant Roots; D043585:Receptor, Muscarinic M2 / Q000037:antagonists & inhibitors; D043587:Receptor, Muscarinic M3 / Q000037:antagonists & inhibitors*; D053629:Thapsia; D019284:Thapsigargin / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D000893:Anti-Inflammatory Agents; D027682:Cation Transport Proteins; D003959:Diamines; D009467:Neuromuscular Depolarizing Agents; D010880:Piperidines; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D013873:Thionucleotides; D006153:Guanosine Diphosphate; D005439:Flufenamic Acid; D019284:Thapsigargin; C023427:guanosine 5'-O-(2-thiodiphosphate); C042375:4-diphenylacetoxy-1,1-dimethylpiperidinium; D002217:Carbachol; D000252:Calcium-Transporting ATPases; C054938:methoctramine; D002118:Calcium