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This Article Full Text Full Text (PDF) All Versions of this Article: 291/3/H1360    most recent 01326.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Vierimaa, H. Articles by Vuolteenaho, O. Search for Related Content PubMed PubMed Citation Articles by Vierimaa, H. Articles by Vuolteenaho, O.

Synergistic activation of salmon cardiac function by endothelin and -adrenergic stimulation

Departments of ¹Physiology and ²Pharmacology and Toxicology, Biocenter Oulu, University of Oulu, Oulu, Finland

Submitted 16 December 2005 ; accepted in final form 14 March 2006

The aim was to find out the effects of endothelin-1 (ET-1) in salmon (Salmo salar) cardiac contractile and endocrine function and its possible interaction with -adrenergic regulation. We found that ET-1 has a positive inotropic effect in salmon heart. ET-1 (30 nM) increased the contraction amplitude 17 ± 4.7% compared with the basal level. -Adrenergic activation (isoprenaline, 100 nM) increased contraction amplitude 30 ± 13.1%, but it did not affect the contractile response to ET-1. ET-1 (10 nM) stimulated the secretion of salmon cardiac natriuretic peptide (sCP) from isolated salmon ventricle (3.3 ± 0.14-fold compared with control) but did not have any effect on ventricular sCP mRNA. Isoprenaline alone (0.1–1,000 nM) did not stimulate sCP release, but ET-1 (10 nM) together with isoprenaline (0.1 nM) caused a significantly greater increase of sCP release than ET-1 alone (5.4 ± 0.07 vs. 3.3 ± 0.14 times increase compared with control). The effects on the contractile and secretory function could be inhibited by a selective ET_A-receptor antagonist BQ-610 (1 µM), whereas ET_B-receptor blockage (by 100 nM BQ-788) enhanced the secretory response. Thus ET-1 is a phylogenetically conserved regulator of cardiac function, which has synergistic action with -adrenergic stimulation. The modulatory effects of ET-1 may therefore be especially important in situations with high -adrenergic tone.

natriuretic peptide; cardiac contractile function