Document Detail


Effect of cholinergic agonists on muscular tonus of the lizard small intestine and esophagus.
MedLine Citation:
PMID:  10530339     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The underlying mechanisms of acetylcholine-induced intestinal relaxation in the lizard Liolaemus tenuis tenuis are still unknown. By using a classical model of intestinal recording of isometric contraction and relaxation in conjunction with specific pharmacological tools, this article studies the possible influence of EDRF/NO and nicotinic ganglionar receptors on the Ach-induced relaxation in an effort to elucidate the probable mechanisms involved in ACh effect. It was observed that the relaxation of the lizard intestine elicited by ACh (10(-7) - 4 x 10(-4) M) was not affected by hexametonium (5 x 10(-4) M) or tetrodotoxin (10(-6) M). Nicotine (10(-7) to 10(-4) M) induced relaxation was significantly antagonized by hexametonium; however, it was not influenced by tetrodotoxin. These results allow us to discard a neuronal pathway in cholinergic-induced relaxation, suggesting a more direct cholinergic effect on the smooth muscle, perhaps mediated by an unknown substance released by some specialized tissue. N-nitro-L-arginine, used to block NO-synthase and NO production, induced no changes in ACh-induced relaxation. Methylene blue, a soluble guanylate cyclase inhibitor, induced no changes in ACh-induced relaxation. These results allow us to discard a probable role of EDRF/nitric oxide in the ACh-induced relaxation of lizard small intestine, providing evidence that this mechanism could be different from that reported in other species.
Authors:
J Wacyk; M Fuenzalida; M Morales; O Acuña; D Lemus
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biological research     Volume:  32     ISSN:  0716-9760     ISO Abbreviation:  Biol. Res.     Publication Date:  1999  
Date Detail:
Created Date:  1999-12-29     Completed Date:  1999-12-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9308271     Medline TA:  Biol Res     Country:  CHILE    
Other Details:
Languages:  eng     Pagination:  29-33     Citation Subset:  IM    
Affiliation:
Institute of Biomedical Sciences (ICBM), Faculty of Medicine, University of Chile, Santiago de Chile.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cholinergic Agonists / pharmacology*
Esophagus / drug effects*
Female
Intestine, Small / drug effects*
Lizards
Male
Muscle Relaxation / drug effects*
Muscle Tonus / drug effects*
Chemical
Reg. No./Substance:
0/Cholinergic Agonists

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


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