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. 1995 Jul;115(5):845–851. doi: 10.1111/j.1476-5381.1995.tb15010.x

BaCl2- and 4-aminopyridine-evoked phasic contractions in the rat vas deferens.

Y Huang 1
PMCID: PMC1908510  PMID: 8548186

Abstract

1. The actions of BaCl2 and 4-aminopyridine, blockers of K+ channels, on the mechanical activity of the epididymal half of the rat vas deferens were investigated. 2. Both BaCl2 and 4-aminopyridine dose-dependently evoked phasic contractions. High extracellular potassium (35-40 mM) caused a tonic contraction but abolished the BaCl2- and 4-aminopyridine-induced phasic activity and reduced the BaCl2-induced sustained component of contraction, but increased the 4-aminopyridine-induced tonic contraction. 3. Omission of calcium from the extracellular medium totally abolished the 4-aminopyridine-induced response but only reduced the mean amplitude of phasic contractions induced by BaCl. 4. Procaine (10 mM), an inhibitor of internal calcium release, completely abolished the phasic activity and reduced the sustained contraction induced by BaCl2. The remaining tone was abolished by nifedipine (1 microM). 5. Tetraethylammonium (1 mM) suppressed the amplitude of the BaCl2-induced phasic contractions, and induced a biphasic increase in tonic tension. 6. The BaCl2-induced responses were resistant to prazosin (1 microM), yohimbine (3 microM), propranolol (3 microM) or atropine (3 microM); in contrast, the 4-aminopyridine-induced activity was effectively inhibited by prazosin (1 microM) attenuated by yohimbine (1 microM) and atropine (1 microM) but not by propranolol (3 microM). The 4-aminopyridine-induced response was abolished by pretreatment of the vas deferens with 6-hydroxydopamine (0.5 mM). 7. The results indicate that the BaCl2-evoked activity in the vas deferens was mainly due to blockade of Ba(2+)-sensitive K+ channels on the smooth muscle plasma membrane. Subsequent calcium entry through the depolarized plasma membrane was needed to trigger generation of phasic contractions.(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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  1. Ahn H. Y., Karaki H. Inhibitory effects of procaine on contraction and calcium movement in vascular and intestinal smooth muscles. Br J Pharmacol. 1988 Jul;94(3):789–796. doi: 10.1111/j.1476-5381.1988.tb11590.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Baba K., Kawanishi M., Satake T., Tomita T. Effects of verapamil on the contractions of guinea-pig tracheal muscle induced by Ca, Sr and Ba. Br J Pharmacol. 1985 Jan;84(1):203–211. doi: 10.1111/j.1476-5381.1985.tb17371.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bean B. P. Classes of calcium channels in vertebrate cells. Annu Rev Physiol. 1989;51:367–384. doi: 10.1146/annurev.ph.51.030189.002055. [DOI] [PubMed] [Google Scholar]
  4. Berridge M. J. Inositol trisphosphate and calcium signalling. Nature. 1993 Jan 28;361(6410):315–325. doi: 10.1038/361315a0. [DOI] [PubMed] [Google Scholar]
  5. Itoh T., Kuriyama H., Suzuki H. Excitation--contraction coupling in smooth muscle cells of the guinea-pig mesenteric artery. J Physiol. 1981 Dec;321:513–535. doi: 10.1113/jphysiol.1981.sp014000. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Janssen L. J., Daniel E. E. Depolarizing agents induce oscillations in canine bronchial smooth muscle membrane potential: possible mechanisms. J Pharmacol Exp Ther. 1991 Oct;259(1):110–117. [PubMed] [Google Scholar]
  7. Khoyi M. A., Dalziel H. H., Zhang L., Bjur R. A., Gerthoffer W. T., Buxton I. L., Westfall D. P. [Ca2+]i-sensitive, IP3-independent Ca2+ influx in smooth muscle of rat vas deferens revealed by procaine. Br J Pharmacol. 1993 Dec;110(4):1353–1358. doi: 10.1111/j.1476-5381.1993.tb13968.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kiyonaga A., Arakawa K., Tanaka H., Shindo M. Blood pressure and hormonal responses to aerobic exercise. Hypertension. 1985 Jan-Feb;7(1):125–131. doi: 10.1161/01.hyp.7.1.125. [DOI] [PubMed] [Google Scholar]
  9. Langton P. D., Nelson M. T., Huang Y., Standen N. B. Block of calcium-activated potassium channels in mammalian arterial myocytes by tetraethylammonium ions. Am J Physiol. 1991 Mar;260(3 Pt 2):H927–H934. doi: 10.1152/ajpheart.1991.260.3.H927. [DOI] [PubMed] [Google Scholar]
  10. Latorre R., Oberhauser A., Labarca P., Alvarez O. Varieties of calcium-activated potassium channels. Annu Rev Physiol. 1989;51:385–399. doi: 10.1146/annurev.ph.51.030189.002125. [DOI] [PubMed] [Google Scholar]
  11. Leijten P. A., van Breemen C. The relationship between noradrenaline-induced contraction and 45Ca efflux stimulation in rabbit mesenteric artery. Br J Pharmacol. 1986 Dec;89(4):739–747. doi: 10.1111/j.1476-5381.1986.tb11178.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Lydrup M. L. Role of K+ channels in spontaneous electrical and mechanical activity of smooth muscle in the guinea-pig mesotubarium. J Physiol. 1991 Feb;433:327–340. doi: 10.1113/jphysiol.1991.sp018428. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Mitra R., Morad M. Ca2+ and Ca2+-activated K+ currents in mammalian gastric smooth muscle cells. Science. 1985 Jul 19;229(4710):269–272. doi: 10.1126/science.2409600. [DOI] [PubMed] [Google Scholar]
  14. Nelson M. T., Standen N. B., Brayden J. E., Worley J. F., 3rd Noradrenaline contracts arteries by activating voltage-dependent calcium channels. Nature. 1988 Nov 24;336(6197):382–385. doi: 10.1038/336382a0. [DOI] [PubMed] [Google Scholar]
  15. Omote M., Kajimoto N., Mizusawa H. The ionic mechanism of phenylephrine-induced rhythmic contractions in rabbit mesenteric arteries treated with ryanodine. Acta Physiol Scand. 1993 Jan;147(1):9–13. doi: 10.1111/j.1748-1716.1993.tb09467.x. [DOI] [PubMed] [Google Scholar]
  16. Quast U. Do the K+ channel openers relax smooth muscle by opening K+ channels? Trends Pharmacol Sci. 1993 Sep;14(9):332–337. doi: 10.1016/0165-6147(93)90006-6. [DOI] [PubMed] [Google Scholar]
  17. Rudy B. Diversity and ubiquity of K channels. Neuroscience. 1988 Jun;25(3):729–749. doi: 10.1016/0306-4522(88)90033-4. [DOI] [PubMed] [Google Scholar]
  18. Standen N. B., Quayle J. M., Davies N. W., Brayden J. E., Huang Y., Nelson M. T. Hyperpolarizing vasodilators activate ATP-sensitive K+ channels in arterial smooth muscle. Science. 1989 Jul 14;245(4914):177–180. doi: 10.1126/science.2501869. [DOI] [PubMed] [Google Scholar]
  19. Suzuki K., Ito K. M., Minayoshi Y., Suzuki H., Asano M., Ito K. Modification by charybdotoxin and apamin of spontaneous electrical and mechanical activity of the circular smooth muscle of the guinea-pig stomach. Br J Pharmacol. 1993 Jul;109(3):661–666. doi: 10.1111/j.1476-5381.1993.tb13624.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Weiss G. B., Pang I. H., Goodman F. R. Relationship between 45Ca movements, different calcium components and responses to acetylcholine and potassium in tracheal smooth muscle. J Pharmacol Exp Ther. 1985 May;233(2):389–394. [PubMed] [Google Scholar]
  21. van Breemen C., Saida K. Cellular mechanisms regulating [Ca2+]i smooth muscle. Annu Rev Physiol. 1989;51:315–329. doi: 10.1146/annurev.ph.51.030189.001531. [DOI] [PubMed] [Google Scholar]

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