Skip to main content
PMC home page
British Journal of Pharmacology logoLink to British Journal of Pharmacology
. 1986 May;88(1):113–120. doi: 10.1111/j.1476-5381.1986.tb09477.x

Effect of apamin on responses to BRL 34915, nicorandil and other relaxants in the guinea-pig taenia caeci.

S W Weir, A H Weston
PMCID: PMC1917124  PMID: 2423171

Abstract

BRL 34915 (4-64 X 10(-7) M), isoprenaline (0.5-32 X 10(-8) M) and nicorandil (4-64 X 10(-6) M) produced a slowly-developing relaxation of spontaneous tone of the guinea-pig taenia caeci; with no after-contraction on washout. These inhibitory responses were unaffected by apamin (10(-7) M). Adenosine triphosphate (0.06-2 X 10(-3) M) and noradrenaline (1-16 X 10(-7) M) produced a rapid inhibition of spontaneous tone with a prominent after-contraction, especially on washout. Both the inhibitory effect and the rebound contraction were abolished by apamin (10(-7) M). Exposure to both BRL 34915 (64 X 10(-7) M) and to nicorandil (64 X 10(-6) M) produced an increase in the 86Rb efflux rate coefficient which was unaffected by apamin (10(-7) M). Exposure to isoprenaline (32 X 10(-8) M) had no effect on the 86Rb efflux rate coefficient. Exposure to noradrenaline (16 X 10(-7) M) produced an increase in the 86Rb efflux rate coefficient which was abolished by apamin (10(-7) M). The results confirm that both BRL 34915 and nicorandil are capable of opening potassium channels in smooth muscle but show that the channel is not apamin-sensitive.

Full text

PDF
113

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Banks B. E., Brown C., Burgess G. M., Burnstock G., Claret M., Cocks T. M., Jenkinson D. H. Apamin blocks certain neurotransmitter-induced increases in potassium permeability. Nature. 1979 Nov 22;282(5737):415–417. doi: 10.1038/282415a0. [DOI] [PubMed] [Google Scholar]
  2. Bolton T. B., Clapp L. H. The diverse effects of noradrenaline and other stimulants on 86Rb and 42K efflux in rabbit and guinea-pig arterial muscle. J Physiol. 1984 Oct;355:43–63. doi: 10.1113/jphysiol.1984.sp015405. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bolton T. B., Lang R. J., Takewaki T., Benham C. D. Patch and whole-cell voltage clamp of single mammalian visceral and vascular smooth muscle cells. Experientia. 1985 Jul 15;41(7):887–894. doi: 10.1007/BF01970006. [DOI] [PubMed] [Google Scholar]
  4. Bülbring E., den Hertog A. The action of isoprenaline on the smooth muscle of the guinea-pig taenia coli. J Physiol. 1980 Jul;304:277–296. doi: 10.1113/jphysiol.1980.sp013324. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Den Hertog A. Calcium and the action of adrenaline, adenosine triphosphate and carbachol on guinea-pig taenia caeci. J Physiol. 1982 Apr;325:423–439. doi: 10.1113/jphysiol.1982.sp014160. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Den Hertog A. Calcium and the alpha-action of catecholamines on guinea-pig taenia caeci. J Physiol. 1981 Jul;316:109–125. doi: 10.1113/jphysiol.1981.sp013776. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Den Hertog A., Pielkenrood J., Ras R., van den Akker J. The contribution of calcium and potassium to the alpha-action of adrenaline on smooth muscle cells of the portal vein, pulmonary artery and taenia caeci of the guinea-pig. Eur J Pharmacol. 1984 Feb 17;98(2):223–234. doi: 10.1016/0014-2999(84)90593-4. [DOI] [PubMed] [Google Scholar]
  8. 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]
  9. Imanishi S., Arita M., Kiyosue T., Aomine M. Effects of SG-75 (nicorandil) on electrical activity of canine cardiac Purkinje fibers: possible increase in potassium conductance. J Pharmacol Exp Ther. 1983 Apr;225(1):198–205. [PubMed] [Google Scholar]
  10. Inoue T., Ito Y., Takeda K. The effects of 2-nicotinamidoethyl nitrate on smooth muscle cells of the dog mesenteric artery and trachea. Br J Pharmacol. 1983 Nov;80(3):459–470. doi: 10.1111/j.1476-5381.1983.tb10716.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Inoue T., Kanmura Y., Fujisawa K., Itoh T., Kuriyama H. Effects of 2-nicotinamidoethyl nitrate (nicorandil; SG-75) and its derivative on smooth muscle cells of the canine mesenteric artery. J Pharmacol Exp Ther. 1984 Jun;229(3):793–802. [PubMed] [Google Scholar]
  12. Kajiwara M., Droogmans G., Casteels R. Effects of 2-nicotinamidoethyl nitrate (Nicorandil) on excitation-contraction coupling in the smooth muscle cells of rabbit ear artery. J Pharmacol Exp Ther. 1984 Aug;230(2):462–468. [PubMed] [Google Scholar]
  13. Karashima T., Itoh T., Kuriyama H. Effects of 2-nicotinamidoethyl nitrate on smooth muscle cells of the guinea-pig mesenteric and portal veins. J Pharmacol Exp Ther. 1982 May;221(2):472–480. [PubMed] [Google Scholar]
  14. Maas A. J., Den Hertog A., Ras R., Van den Akker J. The action of apamin on guinea-pig taenia caeci. Eur J Pharmacol. 1980 Oct 17;67(2-3):265–274. doi: 10.1016/0014-2999(80)90507-5. [DOI] [PubMed] [Google Scholar]
  15. Maas A. J., Den Hertog A. The effect of apamin on the smooth muscle cells of the guinea-pig taenia coli. Eur J Pharmacol. 1979 Sep 15;58(2):151–156. doi: 10.1016/0014-2999(79)90006-2. [DOI] [PubMed] [Google Scholar]
  16. 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]
  17. 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]

Articles from British Journal of Pharmacology are provided here courtesy of The British Pharmacological Society

RESOURCES