title: Arecoline excites the contraction of distal colonic smooth muscle strips in rats via the M3 receptor-extracellular Ca2+ influx - Ca2+ store release pathway.
abstract: Areca is a Chinese herbal medicine that is widely used for constipation. However the mechanisms of its action are not clear. We investigated the effects of arecoline, the most active component of areca, on the motility of rat distal colonic smooth muscle strips. In longitudinal muscle of distal colon (LMDC) and circular muscle of distal colon (CMDC), arecoline increased the contraction in a dose-dependent manner. Tetrodotoxin (TTX) did not inhibit the effects of arecoline. The contractile response to arecoline was completely antagonized by atropine. 4-Diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) strongly depressed the response to arecoline, but gallamine and methoctramine did not. Nifedipine, 2-aminoethoxydiphenyl borate (2-APB), and Ca2+-free Krebs solution with EGTA partly inhibited the effects of arecoline. The sum of Ca2+-free Krebs solution, EGTA, and 2-APB completely inhibited the effects of arecoline. The results show that arecoline stimulates distal colonic contraction in rats via the muscarinic (M3) receptor - extracellular Ca2+ influx - Ca2+ store release pathway. It is likely that the action of areca in relieving constipation is due to its stimulation of muscle contraction.
authors.affiliation: Institute of Physiology, School of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, P. R. China.
authors.forename: Chuan-Bao
authors.initials: CB
authors.lastname: Li
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Wen-Bo
authors.initials: WB
authors.lastname: Tang
authors.forename: Chuan-Yong
authors.initials: CY
authors.lastname: Liu
authors.forename: Dong-Ping
authors.initials: DP
authors.lastname: Xie
mesh_terms: D000818:Animals; D001115:Arecoline / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D018679:Cholinergic Agonists / Q000494:pharmacology; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D003248:Constipation / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000627:therapeutic use; D005260:Female; D066298:In Vitro Techniques; D017136:Ion Transport; D018721:Muscarinic Agonists / Q000494:pharmacology*; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D051381:Rats; D011913:Rats, Inbred BB; D043587:Receptor, Muscarinic M3 / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D018679:Cholinergic Agonists; D004365:Drugs, Chinese Herbal; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D043587:Receptor, Muscarinic M3; D013779:Tetrodotoxin; D001115:Arecoline; D002118:Calcium