Summary
Hypercapnia induces initial constriction and prolonged relaxation of rat small mesenteric arteries. The mechanism of the relaxation is unknown, but has been attributed to lowering of pHi in the vascular smooth muscle. In this study we have investigated the response to raised PCO2 at constant pHo, in mesenteric small arteries precontracted with noradrenaline. 10% CO2 led to a fall in pHi associated with acute potentiation of tension, and subsequent relaxation. The relaxation did not occur in arteries in which the endothelium had been removed, nor in arteries pretreated with the nitric oxide synthase inhibitor, L-NAME (10−4M, NG-nitro-L-arginine methyl ester). The D-enantiomer, D-NAME, was without effect. We conclude that hypercapnic-induced vasodilatation in this circulation occurs via endothelium derived nitric oxide production.
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References
Nielsen H, Aalkjaer C, Mulvany MJ (1991) Differential contractile effects of changes in carbon dioxide tension on rat mesenteric resistance arteries precontracted with noradrenaline. Pflugers Arch 419:51–56
Matthews JG, Graves JE, Poston L (1992) Relationships between pHi and tension in isolated rat mesenteric resistance arteries. J Vasc Res 29:330–340
Wray S (1988) Smooth muscle intracellular pH: Measurement, regulation and function. Am J Physiol 254:C213-C225
Aalkjaer C (1990) Regulation of intracellular pH and its role in vascular smooth muscle function. J Hypertens 8:197–206
McGillivray Anderson KM, Faber JE (1990) Effect of acidosis on contraction of microvascular smooth muscle by α1-and α2-adrenoreceptors. Circ Res 66:1643–1657
Fry CH, Poole-Wilson PA (1981) Effects of acid-base changes on excitation-contraction coupling in the guinea-pig and rabbit cardiac ventricular muscle. J Physiol(Lond) 313:141–160
Fukuda S, Matsumoto M, Nishimura N, Fujiwara N, Shimoji K, Takeshita H, Lee T (1990) Endothelial modulation of norepinephrineinduced constriction of rat aorta at normal and high CO2 tensions. Am J Physiol 258:H1049-H1054
Iadecola C (1992) Does nitric oxide mediate the increases in cerebral blood flow elicited by hypercapnia? Proc Natl Acad Sci 89:3913–3916
Heinzel B, John M, Klatt P, Böhme E, Mayer B (1992) Ca2+/calmodulin-dependentformation of hydrogenperoxide by brain nitric oxide synthase. Biochem J 281:627–630
Adams DJ, Barakeh J, Kaskey R, Van Breemen C (1989) Ion channels and regulation of intracellular calcium in vascular endothelial cells. Faseb J 3:2389–2400
Harder DR (1982) Effect of H+ and elevated PCO2 on membrane electrical properties of rat cerebral arteries. Pflügers Arch 394:182–185
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Carr, P., Graves, J.E. & Poston, L. Carbon dioxide induced vasorelaxation in rat mesenteric small arteries precontracted with noradrenaline is endothelium dependent and mediated by nitric oxide. Pflugers Arch. 423, 343–345 (1993). https://doi.org/10.1007/BF00374415
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DOI: https://doi.org/10.1007/BF00374415