Muscarinic receptor subtypes of the bladder and gastrointestinal tract

スポンサーリンク

概要

• 論文の詳細を見る

• The parasympathetic nervous system is responsible for maintaining normal intestinal and bladder function, contracting the smooth muscle by releasing the neurotransmitters acetylcholine (ACh) and ATP and relaxing sphincters by releasing nitric oxide. ACh is the main transmitter released and smooth muscle contraction is mediated via a mixed M2/M3 receptor population ; M3 receptors acting via phospholipase C and M2 receptors acting via inhibition of adenylate cyclase. In ileal, colonic, gastric and bladder (detrusor) smooth muscle the density of M2 receptors is far greater than the density of M3 receptors, the M2 : M3 ratio being 3 : 1 in most species including man. Despite the predominance of M2-receptors, direct contraction of intestinal and detrusor smooth muscle is mediated via the M3-receptor subtype and only this subtype is involved in contraction in vitro. Furthermore, knocking out the M3-receptor gene can have severe consequences on intestinal and bladder responses. In some tissues however M2-receptors may mediate an indirect "re-contraction" whereby a reduction in adenylate cyclase activity reverses the relaxation induced by β-adrenoceptor stimulation. Thus, intestinal and bladder responses to muscarinic agonists are slightly depressed in M2 receptor knockout mice. The role of receptor subtypes in disease is unclear, but an enhancement of M2 receptor mediated responses has been reported to occur in diabetes. Animal models suggest that M2 receptors may play a greater role in some situations such as in the denervated bladder and intestine. In human disease the mechanisms operating are not so clear. Detrusor sensitivity to muscarinic agonists is enhanced in the neurogenic overactive bladder, but there is controversy surrounding the role of M2 receptors and conflicting results have been reported. Thus, the main muscarinic receptor mediating contraction in normal smooth muscle is the M3 receptor, but M2 receptors are also present and possibly may have an enhanced role in disease.

• 日本平滑筋学会の論文

著者

• UCHIYAMA Toshimitsu

  Departments of Pharmacology Faculty of Medicine, Toho University

• Chess-williams Russell

  Department Of Biomedical Science University Of Sheffield

• Chess-williams Russell

  Department Of Biomedical Science Faculty Of Medicine University Of Sheffield

• Uchiyama Toshimitsu

  Department Of Pharmacology Faculty Of Medicine Toho University

関連論文

• Antitumor activity of Panax ginseng-fruit extract (PG-FE) on Sarcoma-180 bearing mice is based on its cytokine productive effect
• Alpha 2-Adrenoceptor Modulates the Release of Acetylcholine from the Rostral Ventrolateral Medulla in Response to Morphine(Pharmacology)
• Muscarinic receptor subtypes of the bladder and gastrointestinal tract
• Endothelium-Independent Relaxant Effect of 5-Hydroxytryptamine (5-HT) on the Isolated Rabbit Facial Vein
• Alteration of autonomic responses in cardiovascular
• S3-1. Detrusor and Gastroinestinal Smooth Muscle Muscarinic Receptors
• α_-Adrenoceptor Subtype Mediating the Phenylephrine-Induced Contractile Response in Rabbit Corpus Cavernosum Penis

スポンサーリンク