Advanced Search

Journal Navigation

Journal Home

Subscriptions

Archive

Contact Us

Table of Contents

SAGETRACK

Sign In to gain access to subscriptions and/or personal tools.
Journal of the Society for Gynecologic Investigation
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Saved Citations
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Request Reprints
Right arrow Add to My Marked Citations
Citing Articles
Right arrow Citing Articles via Google Scholar
Right arrow Citing Articles via Scopus
Google Scholar
Right arrow Articles by Chan, K. K. H.
Right arrow Articles by Pipkin, F. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chan, K. K. H.
Right arrow Articles by Robinson, G.
Right arrow Articles by Pipkin, F. B.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Differential Sensitivity of Human Nonpregnant and Pregnant Myometrium to Calcitonin Gene-Related Peptide

Kenneth K. H. Chan, MD

Department of Obstetrics and Gynecology and Pathology, University of Nottingham School of Medicine, Queen's Medical Centre, Nottingham, UK; Department of Obstetrics and Gynecology, Box 3, Harbor-HCLA Medical Center, 1000 W. Carson Street, Torrance, CA 90509

Graham Robinson, MD

Fiona Broughton Pipkin, DPhil

Department of Obstetrics and Gynecology and Pathology, University of Nottingham School of Medicine, Queen's Medical Centre, Nottingham, UK

Objectives: Calcitonin gene-related peptide (CGRP) is a smooth musicle relaxant with potent vasodilating properties. To investigate its inhibitory effects on human myometrial contractions, we obtained excised human myometria from term pregnant, with and without spontaneous labor, and nonpregnant patients.

Methods: Myometrial strips were mounted in tissue baths in which contractile activity was recorded. Spontaneously contracting tissues in vitro were exposed to increasing concentations of CGRP (10-13-10-7 mol/L). Tissues without spontaneous contractions were induced to contract with either oxytocin or KCl before being exposed to CGRP. The IC25 (CGRP ocncentration required to inhibit contracitility by 25%) was used as comparison between groups.

Results: Tissues with spontaneous or oxytocin-induced in vitro contractions responded equally to CGRP relaxation. Tissues induced to contract with KCl in vitro required approximately 2000 times more CGRP for equal relaxation. In tissues with spontaneous or oxytocin-induced in vitro contractions, those from pregnant unlabored patients were 60 times more sensitive to CGRP than those from pregnant labored or nonpregnant patients. The latter two groups responded equally to CGRP.

Conclusions: The sensitivity of myometrial tissues to CGRP relaxation in vitro is increased from the nonpregnant to the pregnant term state. This increased sensitivity is lost once patients develop spontaneous term labor. The relative ineffectiveness of CGRP in relaxing KCl-induced in vitro contractions probably reflects its known mechanism of action, namely the hyperpolarization of cell membrane potentials via activation of membrane potassium channels.

Key Words: Calcitonin gene-related peptide • myometrial contractility • pregnancy

Journal of the Society for Gynecologic Investigation, Vol. 4, No. 1, 15-21 (1997)
DOI: 10.1177/107155769700400103
Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?