Distinct contractile systems for electromechanical and pharmacomechanical coupling in smooth muscle

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Item Type:	Article
Title:	Distinct contractile systems for electromechanical and pharmacomechanical coupling in smooth muscle
Creators Name:	Lamounier-Zepter, V., Baltas, L.G. and Morano, I.
Abstract:	Electromechanical coupling by KCl depolarization of bladder preparations elicits an initial phasic and subsequent tonic contraction. Using a smooth-muscle myosin heavy chain (SM-MyHC) knock-out mouse model we could previously demonstrate, that phasic and tonic contraction of intact neonatal bladder preparations could be elicited through the recruitment of SM-MyHC and non-muscle myosin heavy chains (NM-MyHC), respectively. Inhibition of myosin light chain kinase (MLCK) by ML-7 eliminated the phasic contraction of wild-type (+/+), rather than tonic contraction of neonatal bladder strips prepared from both +/+ and homozygous SM-MyHC knock-out (-/-) mice. Pharmacomechanical coupling upon PDBu-induced activation of protein kinase C of neonatal bladder preparations elicited tonic contraction of both +/+ and -/- murine. We suggest that: i) electromechanical coupling activates both SM-MyHC and NM-MyHC systems via a ML-7 sensitive and insensitive pathway, respectively. ii) Pharmacomechanical coupling recruits part of the NM-MyHC system rather than SM-MyHC.
Keywords:	13-Dibutyrate Phorbol 12, Alternative Splicing, Azepines, Drug Dose-Response Relationship, Electrophysiology, Enzyme Inhibitors, Exons, Genotype, Homozygote, Inbred C57BL Mice, Knockout Mice, Muscle Contraction, Myosins, Naphthalenes, Newborn Animals, Phosphorylation, Potassium Chloride, Smooth Muscle, Transgenic Mice, Protein Isoforms, Protein Kinase C, Animals, Mice
Source:	Advances in Experimental Medicine and Biology
ISSN:	0065-2598
Publisher:	Springer
Volume:	538
Page Range:	417-425
Date:	1 January 2003
Official Publication:	https://doi.org/10.1007/978-1-4419-9029-7_39
PubMed:	View item in PubMed

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