Abstract
Diabetes-induced changes in the calcium influx and contractile responses of aortic rings to various drugs were investigated in streptozotocin-treated rats. Diabetes is associated with calcium influx into the aortic rings (1.5-and 2.5-fold, respectively, after either KCl or noradrenaline stimulation compared with normal). The maximum KCl-induced contraction of the arorta in diabetic rats was reduced by 38%, but the EC50 of KCl remained unchanged. The pA2 of nifedipine for inhibiting the contractile response of aorta to KCl decreased one order of magnitude in the diabetic rats (8.26 vs 9.03 for non-diabetic rats). It is concluded that diabetes reduces the sensitivity of aortic tissue to nifedipine and may affect the stimulation-contraction coupling of vascular smooth muscle in such a way that a higher influx of calcium results after stimulation and that this may be responsible for diabetes-induced vascular complications.
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References
Pyrala K, Diabetes and coronary heart disease. Acta Endocrinol 272 (Suppl): 11–19, 1985
Fleckenstein A, Frey M, Zorn J, Fleckenstein-Grun G, The role of calcium in the pathogenesis of experimental arteriosclerosis. Trends Pharmacol Sci 8:496–501, 1987
Srivastava LM, Bora PS, Bhatt SD, Diabetogenic action of streptozotocin. Trends Pharmacol Sci 3:377–379, 1982
Head RJ, Longhurst PA, Panek RL, Stitzel RE, A contrasting effect of the diabetic state upon the contractile responses of aortic preparations from the rat and rabbit. Br J Pharmacol 91:275–286, 1988
Meisherri KD, Hwang OK, Van Breemen C, Evidence for two separate Ca2+ pathways in smooth muscle plasmalemma. J Membr Biol 59:19–25, 1981
Hof RP, Hof A, Vasoconstrictor and vasodilator effects in normal and atherosclerotic conscious rabbits. Br J Pharmacol 95:1075–1080, 1988
MacLeod KM, McNeill JH, Alpha-adrenoceptor mediated responses in aorta from three months streptozotocin diabetic rats. Proc West Pharmacol Soc 25:245–247, 1982
Harris KH, MacLeod KM, Influence of the endothelium on contractile responses of arteries from diabetic rats. Eur J Pharmacol 153:55–64, 1988
Moorhouse JA, Carter SA, Doupe J, Vascular responses in diabetic peripheral neuropathy. Br Med J 1:363–366, 1966
Mahmoudian M, Mobasheri T, The calcium-induced contractions of K+-depolarized ileum and its inhibition by nifedipine in the diabetic rats. Eur J Pharmacol 183:249, 1990
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Mahmoudian, M., Behnaz, F. & Rezaei, E. Diabetes-induced changes in the contractility of the aorta and pA2 of nifedipine in the rat. Acta Diabetol 33, 114–117 (1996). https://doi.org/10.1007/BF00569420
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DOI: https://doi.org/10.1007/BF00569420