Comparison of Inhibitory Effects of Calcium Channel Blockers and That of a Calmodulin Antagonist in Strips of Mesenteric Arteries from Spontaneously Hypertensive and Normotensive Rats

[摘要] References(36)Cited-By(4)Effects of calcium channel blockers and of calmodulin antagonist on the contractile responses to norepinephrine (NE) were compared between strips of mesenteric arteries from 6- and 14-week-old spontaneously hypertensive rats (SHR) and age-matched, normotensive Wistar-Kyoto rats (WKY). The ratio of the maximum contraction developed by NE to that by 60 mM KCI was significantly increased in strips from 14-week-old SHR. Niludipine, verapamil and diltiazem antagonized the maximum NE contraction to a greater extent in strips from 14-week-old SHR than in those from the WKY. However, the antagonism by niludipine of the KCI- or caffeine-induced contraction was not significantly different between the strips from 14-week-old SHR and those from WKY. In strips from 6-week-old rats, there was no difference in the antagonism by niludipine of the maximum NE contraction. On the other hand, the effect of W-7 on the maximum N E contraction was not significantly different between the strips from 14-week-old SHR and those from WKY. Schild plot analyses demonstrated that a, -adrenoceptors were the same for the strips from SHR and WKY. These results suggest that the enhanced maximum NE contraction in the mesenteric artery from 14-week-old SHR reflects the increased transmembrane influx of calcium, and the activity of calmodulin seems to be the same for the two strains.

[学科分类] 药理学