ISSN:
1573-4919
Keywords:
calcium
;
harmaline
;
smooth muscle
;
sodium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Summary The effect of changing the extracellular concentration of both Na+ and K+ on the longitudinal muscle of the guinea-pig ileum was studied in the presence and absence of harmaline. A decrease in extracellular Na+ concentration was found to produce a dose-dependent contractile response, which may suggest the existence of a Na...Ca exchange mechanism in this muscle. Harmaline (2 × 10−4 M) was found to reversibly inhibit this contraction and was also found to selectively block the tonic component of high-K induced contradictions. In view of the fact that harmaline is a non-competitive inhibitor of Ca-induced contractions (Hider et al., Europ. J. Pharmacol., 71, 87, 1981), the action of harmaline was interpreted as being a specific inhibitor of the Na... exchange mechanism, binding specifically to Na+ coordination sites.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02370173
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