PURPOSE: Essential arterial hypertension is a frequent condition. Spontaneously hypertensive rats (SHRs) show bladder dysfunction similar to that seen in patients with overactive bladder. Since muscarinic receptors and rho-kinase have a key role in the regulation of bladder contractility, we determined whether alterations of either one might contribute to hypertension associated bladder dysfunction. MATERIALS AND METHODS: The bladders of SHRs and normotensive Wistar Kyoto rats (WKYs) were compared in in vitro radioligand binding and contractility studies. RESULTS: The mean total number of muscarinic receptors +/- SEM (181 +/- 14 vs 191 +/- 22 fmol/mg protein) and the relative roles of their subtypes were similar in SHRs and WKYs. Contractile responses to the muscarinic agonist carbachol (maximum effect 2.04 +/- 0.24 vs 2.05 +/- 0.14 mN/mm strip length and -log EC50 5.61 +/- 0.07 vs 5.64 +/- 0.04) and to KCl in a receptor independent manner were similar in the 2 strains. The M3 selective antagonist darifenacin inhibited carbachol responses much more potently than the M2 selective antagonist methoctramine but the potency of the 2 drugs was similar in each strain. The rho-kinase inhibitor Y27,632 attenuated carbachol induced contraction in a quantitatively similar manner in SHRs and WKYs. CONCLUSIONS: An altered function of muscarinic receptor subtypes or rho-kinase does not appear to contribute to bladder dysfunction in SHRs.
PURPOSE: Essential arterial hypertension is a frequent condition. Spontaneously hypertensiverats (SHRs) show bladder dysfunction similar to that seen in patients with overactive bladder. Since muscarinic receptors and rho-kinase have a key role in the regulation of bladder contractility, we determined whether alterations of either one might contribute to hypertension associated bladder dysfunction. MATERIALS AND METHODS: The bladders of SHRs and normotensive Wistar Kyoto rats (WKYs) were compared in in vitro radioligand binding and contractility studies. RESULTS: The mean total number of muscarinic receptors +/- SEM (181 +/- 14 vs 191 +/- 22 fmol/mg protein) and the relative roles of their subtypes were similar in SHRs and WKYs. Contractile responses to the muscarinic agonist carbachol (maximum effect 2.04 +/- 0.24 vs 2.05 +/- 0.14 mN/mm strip length and -log EC50 5.61 +/- 0.07 vs 5.64 +/- 0.04) and to KCl in a receptor independent manner were similar in the 2 strains. The M3 selective antagonist darifenacin inhibited carbachol responses much more potently than the M2 selective antagonist methoctramine but the potency of the 2 drugs was similar in each strain. The rho-kinase inhibitor Y27,632 attenuated carbachol induced contraction in a quantitatively similar manner in SHRs and WKYs. CONCLUSIONS: An altered function of muscarinic receptor subtypes or rho-kinase does not appear to contribute to bladder dysfunction in SHRs.
Authors: Tim Schneider; Peter Hein; Martina B Michel-Reher; Martin C Michel Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2005-07-30 Impact factor: 3.000
Authors: Elfaridah P Frazier; Stephan L M Peters; Alan S Braverman; Michael R Ruggieri; Martin C Michel Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2007-12-04 Impact factor: 3.000
Authors: Hana Cernecka; Kim Kersten; Harm Maarsingh; Carolina R Elzinga; Igle Jan de Jong; Cees Korstanje; Martin C Michel; Martina Schmidt Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2015-05-09 Impact factor: 3.000