Document Detail


Gastrin-releasing peptide is a transmitter mediating porcine gallbladder contraction.
MedLine Citation:
PMID:  1708207     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We studied the role of gastrin-releasing peptide (GRP) for porcine gallbladder motility. Immunohistochemistry visualized nerve fibers containing GRP-like immunoreactivity in muscularis. GRP concentration dependently stimulated contractions of muscularis strips (ED50, 2.9 nM). Neuromedin B was less potent (ED50, 0.1 microM), suggesting existence of GRP-preferring receptors. GRP-induced contractions were unaffected by muscarinic antagonism (1 microM atropine), axonal blockade (1 microM tetrodotoxin), cholecystokinin (CCK) receptor antagonism (10 microM MK-329), or substance P desensitization (1 microM), supporting the existence of myogenic GRP receptors. The bombesin (BN) analogue D-Phe6-BN-(6-13)propylamide (PA) stimulated contractions (ED50, 3.3 nM) with low efficacy (29% of that of GRP). D-Phe6-BN-(6-13)PA (1 microM) shifted GRP concentration-response curves one log to the right. D-Phe6-BN-(6-13)PA interacted specifically with GRP receptors; while abolishing responses to GRP (1 nM), responses to substance P (0.1 microM) and CCK-8 (1 nM) were unchanged. Electrical stimulation (10 Hz, 0.5 ms, 10 V) caused a rapid onset-slow offset, tetrodotoxin-sensitive excitation. Atropine reduced the amplitude to 58% and caused a delayed, slow onset-slow decline response. D-Phe6-BN-(6-13)PA reduced the amplitude to 59% and caused a very rapid onset-rapid decline response. Atropine plus D-Phe6-BN-(6-13)PA abolished responses to nerve stimulation. Nerve stimulation caused significant release of GRP-like immunoreactivity. Thus two neural inputs were defined: a cholinergic rapid onset-rapid offset excitation and a delayed, slow onset-slow offset excitation caused by release and subsequent binding of GRP to GRP-preferring receptors.
Authors:
B Schjoldager; S S Poulsen; P Schmidt; D H Coy; J J Holst
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  260     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1991 Apr 
Date Detail:
Created Date:  1991-05-17     Completed Date:  1991-05-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  G577-85     Citation Subset:  IM    
Affiliation:
Department of Medical Physiology C, Panum Institute, University of Copenhagen, Denmark.
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MeSH Terms
Descriptor/Qualifier:
Animals
Atropine / pharmacology
Carbachol / pharmacology
Electric Stimulation
Gallbladder / drug effects,  innervation,  physiology*
Gastrin-Releasing Peptide
Gastrointestinal Hormones / pharmacology*
Kinetics
Muscle Contraction / drug effects*
Muscle, Smooth / drug effects,  innervation,  physiology*
Nerve Fibers / physiology
Neurokinin B / analogs & derivatives,  pharmacology
Peptides / analysis,  pharmacology*,  physiology
Sincalide / pharmacology
Substance P / analysis,  pharmacology,  physiology
Swine
Tetrodotoxin / pharmacology
Chemical
Reg. No./Substance:
0/Gastrointestinal Hormones; 0/Peptides; 25126-32-3/Sincalide; 33507-63-0/Substance P; 4368-28-9/Tetrodotoxin; 51-55-8/Atropine; 51-83-2/Carbachol; 80043-53-4/Gastrin-Releasing Peptide; 86933-75-7/Neurokinin B; 87096-84-2/neuromedin B

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


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