Signal transduction underlying carbachol-induced contraction of human urinary bladder.
The present study was designed to reexamine the muscarinic acetylcholine receptor subtype mediating carbachol-induced contraction of human urinary bladder and to investigate the underlying signal transduction. Based upon the nonselective tolterodine, the highly M(2)-selective (R)-4-[2-[3-(4-methoxy-benzoylamino)-benzyl]-piperidin-1-ylmethyl]piperidine-1-carboxylic acid amide (Ro-320-6206), and the highly M(3)-selective darifenacin and 3-(1-carbamoyl-1,1-diphenylmethyl)-1-(4-methoxyphenylethyl)pyrrolidine (APP), contraction occurs via M(3) receptors. The phospholipase C inhibitor 1-(6-[([17beta]-3-methoxyestra-1,3,5[10]-trien-17-yl)amino]hexyl)-1H-pyrrole-2,5-dione (U 73,122) (1-10 microM) did not significantly affect carbachol-stimulated bladder contraction. The phospholipase D inhibitor butan-1-ol relative to its negative control butan-2-ol (0.3% each) caused small but detectable inhibition of carbachol-induced bladder contraction. The Ca(2+) entry blocker nifedipine (10-100 nM) strongly inhibited carbachol-induced bladder contraction. In contrast, 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole HCl (SK&F 96,365) (1-10 microM), an inhibitor of store-operated Ca(2+) channels, caused little inhibition. The protein kinase C inhibitor bisindolylmaleimide I (1-10 microM) did not significantly affected carbachol-induced bladder contraction. In contrast, trans-4-[(1R)-1-aminoethyl]-N-4-pyridinylcyclohexanecarboxamide (Y 27,632) (1-10 microM), an inhibitor of rho-associated kinases, concentration dependently and effectively attenuated the carbachol responses. We conclude that carbachol-induced contraction of human urinary bladder via M(3) receptors largely depends on Ca(2+) entry through nifedipine-sensitive channels and activation of a rho kinase, whereas phospholipase D and store-operated Ca(2+) channels contribute only in a minor way. Surprisingly, phospholipase C or protein kinase C do not seem to be involved to a relevant extent.
Schneider
Tim
T
Department of Medicine, University of Essen, Germany.
Fetscher
Charlotte
C
Krege
Susanne
S
Michel
Martin C
MC
D020746:Calcium Channels, L-Type / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology*; D018679:Cholinergic Agonists / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D010739:Phospholipase D / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D043585:Receptor, Muscarinic M2 / Q000378:metabolism; D043587:Receptor, Muscarinic M3 / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology; D014590:Uterine Contraction / Q000187:drug effects*
D020746:Calcium Channels, L-Type; D018679:Cholinergic Agonists; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D002217:Carbachol; D011493:Protein Kinase C; D010738:Type C Phospholipases; D010739:Phospholipase D