Increased vascular contractile sensitivity to serotonin in spontaneously hypertensive is linked with increased turnover of phosphoinositide
Abstract
This study was conducted to determine if increased vascular contractile sensitivity to serotonin in spontaneously hypertensive (SHR) rats is linked with increased phosphoinositide turnover. Aortic and mesenteric artery rings from SHR exhibited 6.2- and 5.0-fold greater contractile sensitivity to serotonin than the aortic and mesenteric artery rings from normotensive Wistar-Kyoto (WKY) rats. Serotonin-induced turnover of phosphoinositide was measured by quantifying the accumulation of [3H] inositol labeled monophosphate (IP), inositol bisphosphate (IP2) and inositol trisphosphate (IP3). Serotonin (3, 30, 200 μM) induced siginificantly greater accumulation of IP in SHR (279%, 590%, 895%) than in WKY (24%, 127%, 328%) aortic rings. Similarly, 3, 30 and 200 μM serotonin induced significantly greater accumulation of IP2 (118%, 241%, 451%) and IP3 (90%, 100%, 247%) in SHR than the accumualation of IP2 (15%, 58%, 122%) and IP3 (19%, 27%, 73%) in WKY aortic rings. Based on these data it is suggested that the greater vascular sensitivity to serotonin in SHR, at least in part, is attributable to increased turnover of phosphoinositide.
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Biochemical characterization of the mechanisms involved in the 5-hydroxytryptamine-induced increase in rat atrial rate
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Signal transduction mechanisms of the vasoconstriction in hypertension
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