Abstract
1. The negative inotropic effects of nicorandil, a nitrate with K-channel opening properties, have been compared with those of pinacidil, cromakalim and nifedipine, in canine right atrial muscle. 2. Cromakalim, pinacidil and nicorandil all produced a negative inotropic effect. However, even at their maximally effective concentrations, the force of contraction remained at about 10% of control levels, whereas contraction was abolished by nifedipine. 3. The pD2 values for the negative inotropic effects of cromakalim, pinacidil and nicorandil were 5.93, 5.37, and 4.35, respectively. 4. The negative inotropic effects of cromakalim (3 x 10(-5)M), pinacidil (3 x 10(-5) M and 3 x 10(-4) M) and nicorandil (3 x 10(-5) M) were not accompanied by changes in cyclic AMP and cyclic GMP levels, whereas that of 3 x 10(-4) M nicorandil was accompanied by an increase in cyclic GMP but not cyclic AMP concentrations. 5. The negative inotropic effect produced by 3 x 10(-4) M nicorandil was greatly reduced by 10(-2) M tetraethylammonium, whereas the increase in cyclic GMP produced by this concentration of nicorandil was not significantly changed. Sodium nitroprusside (10(-3) M) produced a large increase in cyclic GMP concentrations but had no significant negative inotropic effect. 6. It is concluded that the negative inotropic effects of nicorandil like those of cromakalim and pinacidil do not result from an increase in cyclic GMP concentrations. Instead these effects may be due to their action as K-channel openers.
Full text
PDF





Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allen S. L., Boyle J. P., Cortijo J., Foster R. W., Morgan G. P., Small R. C. Electrical and mechanical effects of BRL34915 in guinea-pig isolated trachealis. Br J Pharmacol. 1986 Oct;89(2):395–405. doi: 10.1111/j.1476-5381.1986.tb10273.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Allen S. L., Foster R. W., Morgan G. P., Small R. C. The relaxant action of nicorandil in guinea-pig isolated trachealis. Br J Pharmacol. 1986 Jan;87(1):117–127. doi: 10.1111/j.1476-5381.1986.tb10163.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Arrigoni-Martelli E., Nielsen C. K., Olsen U. B., Petersen H. J. N''-cyano-N-4-pyridyl-N'-1,2,2-trimethylpropylguanidine, monohydrate (P 1134): a new, potent vasodilator. Experientia. 1980 Apr 15;36(4):445–447. doi: 10.1007/BF01975139. [DOI] [PubMed] [Google Scholar]
- Bray K. M., Newgreen D. T., Small R. C., Southerton J. S., Taylor S. G., Weir S. W., Weston A. H. Evidence that the mechanism of the inhibitory action of pinacidil in rat and guinea-pig smooth muscle differs from that of glyceryl trinitrate. Br J Pharmacol. 1987 Jun;91(2):421–429. doi: 10.1111/j.1476-5381.1987.tb10297.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Buckingham R. E., Clapham J. C., Hamilton T. C., Longman S. D., Norton J., Poyser R. H. BRL 34915, a novel antihypertensive agent: comparison of effects on blood pressure and other haemodynamic parameters with those of nifedipine in animal models. J Cardiovasc Pharmacol. 1986 Jul-Aug;8(4):798–804. doi: 10.1097/00005344-198709010-00022. [DOI] [PubMed] [Google Scholar]
- Coraboeuf E., Vassort G. Effects of some inhibitors of ionic permeabilities on ventricular action potential and contraction of rat and guinea-pig hearts. J Electrocardiol. 1968;1(1):19–29. doi: 10.1016/s0022-0736(68)80005-6. [DOI] [PubMed] [Google Scholar]
- Endoh M., Iijima T. Effects of nicorandil and its interaction with isoproterenol on force of contraction and cyclic nucleotide levels of canine atrial muscle: comparison with carbachol. J Cardiovasc Pharmacol. 1983 Sep-Oct;5(5):878–882. doi: 10.1097/00005344-198309000-00027. [DOI] [PubMed] [Google Scholar]
- Endoh M., Taira N. Relationship between relaxation and cyclic GMP formation caused by nicorandil in canine mesenteric artery. Naunyn Schmiedebergs Arch Pharmacol. 1983 May;322(4):319–321. doi: 10.1007/BF00508349. [DOI] [PubMed] [Google Scholar]
- Endoh M., Yamashita S. Differential responses to carbachol, sodium nitroprusside and 8-bromo-guanosine 3',5'-monophosphate of canine atrial and ventricular muscle. Br J Pharmacol. 1981 Jun;73(2):393–399. doi: 10.1111/j.1476-5381.1981.tb10434.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Endoh M., Yamashita S., Taira N. Positive inotropic effect of amrinone in relation to cyclic nucleotide metabolism in the canine ventricular muscle. J Pharmacol Exp Ther. 1982 Jun;221(3):775–783. [PubMed] [Google Scholar]
- Fleckenstein A., Tritthart H., Döring H. J., Byon K. Y. BAY a 1040--ein hochaktiver Ca -antagonistischer Inhibitor der elektro-mechanischen Koppelungsprozesse im Warmblüter-Myokard. Arzneimittelforschung. 1972 Jan;22(1):22–33. [PubMed] [Google Scholar]
- Groschner K., Holzmann S., Kukovetz W. R. Lack of second messenger function of cyclic GMP in acetylcholine-induced negative inotropism. J Cardiovasc Pharmacol. 1986 Nov-Dec;8(6):1154–1157. doi: 10.1097/00005344-198611000-00009. [DOI] [PubMed] [Google Scholar]
- Hamilton T. C., Weir S. W., Weston A. H. Comparison of the effects of BRL 34915 and verapamil on electrical and mechanical activity in rat portal vein. Br J Pharmacol. 1986 May;88(1):103–111. doi: 10.1111/j.1476-5381.1986.tb09476.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Holzmann S. Cyclic GMP as possible mediator of coronary arterial relaxation by nicorandil (SG-75). J Cardiovasc Pharmacol. 1983 May-Jun;5(3):364–370. doi: 10.1097/00005344-198305000-00004. [DOI] [PubMed] [Google Scholar]
- Iijima T., Taira N. Modification by nicorandil and carbachol of the inward calcium current in single cells of the guinea-pig heart. Tohoku J Exp Med. 1986 Dec;150(4):475–479. doi: 10.1620/tjem.150.475. [DOI] [PubMed] [Google Scholar]
- Iijima T., Taira N. Pinacidil increases the background potassium current in single ventricular cells. Eur J Pharmacol. 1987 Sep 2;141(1):139–141. doi: 10.1016/0014-2999(87)90421-3. [DOI] [PubMed] [Google Scholar]
- Kauffman R. F., Schenck K. W., Conery B. G., Cohen M. L. Effects of pinacidil on serotonin-induced contractions and cyclic nucleotide levels in isolated rat aortae: comparison with nitroglycerin, minoxidil, and hydralazine. J Cardiovasc Pharmacol. 1986 Nov-Dec;8(6):1195–1200. doi: 10.1097/00005344-198611000-00015. [DOI] [PubMed] [Google Scholar]
- Morad M., Trautwein W. The effect of the duration of the action potential on contraction in the mammalian heart muscle. Pflugers Arch Gesamte Physiol Menschen Tiere. 1968;299(1):66–82. doi: 10.1007/BF00362542. [DOI] [PubMed] [Google Scholar]
- Parker R. B., Waud D. R. Pharmacological estimation of drug-receptor dissociation constants. Statistical evaluation. I. Agonists. J Pharmacol Exp Ther. 1971 Apr;177(1):1–12. [PubMed] [Google Scholar]
- Scholtysik G. Evidence for inhibition by ICS 205-930 and stimulation by BRL 34915 of K+ conductance in cardiac muscle. Naunyn Schmiedebergs Arch Pharmacol. 1987 Jun;335(6):692–696. doi: 10.1007/BF00166988. [DOI] [PubMed] [Google Scholar]
- Taira N., Satoh K., Yanagisawa T., Imai Y., Hiwatari M. Pharmacological profile of a new coronary vasodilator drug, 2-nicotinamidoethyl nitrate (SG-75). Clin Exp Pharmacol Physiol. 1979 May-Jun;6(3):301–316. doi: 10.1111/j.1440-1681.1979.tb01252.x. [DOI] [PubMed] [Google Scholar]
- Uchida Y., Yoshimoto N., Murao S. Effect of 2-nicotinamidethyl nitrate (SG 75) on coronary circulation. Jpn Heart J. 1978 Jan;19(1):112–124. doi: 10.1536/ihj.19.112. [DOI] [PubMed] [Google Scholar]
- Weir S. W., Weston A. H. The effects of BRL 34915 and nicorandil on electrical and mechanical activity and on 86Rb efflux in rat blood vessels. Br J Pharmacol. 1986 May;88(1):121–128. doi: 10.1111/j.1476-5381.1986.tb09478.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yanagisawa T., Endoh M., Taira N. Involvement of cyclic AMP in the positive inotropic effect of OPC-8212, a new cardiotonic agent, on the canine ventricular muscle. Jpn J Pharmacol. 1984 Nov;36(3):379–388. doi: 10.1254/jjp.36.379. [DOI] [PubMed] [Google Scholar]
- Yanagisawa T., Satoh K., Taira N. Circumstantial evidence for increased potassium conductance of membrane of cardiac muscle by 2-nicotinamidoethyl nitrate (SG-75). Jpn J Pharmacol. 1979 Oct;29(5):687–694. doi: 10.1254/jjp.29.687. [DOI] [PubMed] [Google Scholar]
- Yanagisawa T., Taira N. Effect of 2-nicotinamidethyl nitrate (SG-75) on the membrane potential of left atrial muscle fibres of the dog. Increase in potassium conductance. Naunyn Schmiedebergs Arch Pharmacol. 1980 May;312(1):69–76. doi: 10.1007/BF00502577. [DOI] [PubMed] [Google Scholar]
