ISSN:
1432-2013
Keywords:
Key words Testicular artery
;
Length-tension relationship
;
Nitric oxide
;
Endothelium
;
Endothelium derived contractile factor(s)
;
Prostanoids
;
Testis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract We have investigated the wall tension characteristics and the role of endothelium on vascular tone, at rest and under K+ depolarization, in isolated rings from the pig capsular testicular artery. The active tension reached a maximum that was significantly lower in vessels without endothelium, whereas the passive tension and the Ca2+-dependent myogenic tone were not significantly affected by endothelium removal. Both N G-nitro-l-arginine (L-NOARG, 10−4 M) and methylene blue (10−5 M), increased the basal resting tension (BRT) in vessels with endothelium, while indomethacin (10−6 M) decreased BRT in vessels both with and without endothelium. Either removal of endothelium or treatment with indomethacin (10−6 M), quinacrine (10−5 M) or ibuprofen (10−5 M), significantly depressed the K+ concentration response curve, while dazoxiben (10−5 M) and SQ 30,741 (10−5 M) had no effect. L-NOARG (10−6 M) potentiated the contractile response to K+ in vessels with endothelium, whereas L-NOARG (10−4 M) was ineffective in vessels devoid of endothelium. These results suggest that a predominating NO release from endothelium, together with a cyclooxygenase-derived vasoconstrictor, modulate vascular tone at rest. In contrast, predominant endothelial release of a cyclooxygenase-derived contractile factor, but different from TXA2, PGH2 or superoxide anions, is induced by K+ depolarization and leads to vasoconstriction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004240050249
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