Document Detail


Regulation of alpha1-adrenoceptor-mediated contractions of uterine arteries by PKC: effect of pregnancy.
MedLine Citation:
PMID:  16699075     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Protein kinase C (PKC) plays an important role in the regulation of uterine artery contractility and its adaptation to pregnancy. The present study tested the hypothesis that PKC differentially regulates alpha(1)-adrenoceptor-mediated contractions of uterine arteries isolated from nonpregnant (NPUA) and near-term pregnant (PUA) sheep. Phenylephrine-induced contractions of NPUA and PUA sheep were determined in the absence or presence of the PKC activator phorbol 12,13-dibutyrate (PDBu). In NPUA sheep, PDBu produced a concentration-dependent potentiation of phenylephrine-induced contractions and shifted the dose-response curve to the left. In contrast, in PUA sheep, PDBu significantly inhibited phenylephrine-induced contractions and decreased their maximum response. Simultaneous measurement of contractions and intracellular free Ca(2+) concentrations ([Ca(2+)](i)) in the same tissues revealed that PDBu inhibited phenylephrine-induced [Ca(2+)](i) and contractions in PUA sheep. In NPUA sheep, PDBu increased phenylephrine-induced contractions without changing [Ca(2+)](i). Western blot analysis showed six PKC isozymes, alpha, beta(I), beta(II), delta, epsilon, and zeta, in uterine arteries, among which beta(I), beta(II), and zeta isozymes were significantly increased in PUA sheep. In contrast, PKC-alpha was decreased in PUA sheep. In addition, analysis of subcellular distribution revealed a significant decrease in the particulate-to-cytosolic ratio of PKC-epsilon in PUA compared with that in NPUA sheep. The results suggest that pregnancy induces a reversal of PKC regulatory role on alpha(1)-adrenoceptor-mediated contractions from a potentiation in NPUA sheep to an inhibition in PUA sheep. The differential expression of PKC isozymes and their subcellular distribution in uterine arteries appears to play an important role in the regulation of Ca(2+) mobilization and Ca(2+) sensitivity in alpha(1)-adrenoceptor-mediated contractions and their adaptation to pregnancy.
Authors:
Hongying Zhang; Daliao Xiao; Lawrence D Longo; Lubo Zhang
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-05-12
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  291     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2006 Nov 
Date Detail:
Created Date:  2006-10-10     Completed Date:  2007-01-12     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2282-9     Citation Subset:  IM    
Affiliation:
Center for Perinatal Biology, Dept. of Physiology and Pharmacology, Loma Linda Univ. School of Medicine, Loma Linda, CA 92350, USA. lzhang@llu.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Arteries / drug effects*,  physiology
Calcium / analysis,  metabolism
Dose-Response Relationship, Drug
Female
Isometric Contraction / drug effects
Phenylephrine / pharmacology
Phorbol 12,13-Dibutyrate / pharmacology
Potassium Chloride / pharmacology
Pregnancy
Pregnancy, Animal / physiology*
Protein Kinase C / pharmacology*
Receptors, Adrenergic, alpha-1 / agonists,  drug effects*,  metabolism
Sheep
Uterine Contraction / drug effects*,  physiology
Uterus / blood supply*
Grant Support
ID/Acronym/Agency:
HD-31226/HD/NICHD NIH HHS; HL-57787/HL/NHLBI NIH HHS; HL-67745/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Receptors, Adrenergic, alpha-1; 37558-16-0/Phorbol 12,13-Dibutyrate; 59-42-7/Phenylephrine; 7440-70-2/Calcium; 7447-40-7/Potassium Chloride; EC 2.7.11.13/Protein Kinase C

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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