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. 1990 Jan;420:47–71. doi: 10.1113/jphysiol.1990.sp017901

The activation of calcium and calcium-activated potassium channels in mammalian colonic smooth muscle by substance P.

E A Mayer 1, D D Loo 1, W J Snape Jr 1, G Sachs 1
PMCID: PMC1190038  PMID: 1691293

Abstract

1. The regulation of Ca2(+)-activated K+ channels by the agonist substance P in freshly dissociated smooth muscle cells from the rabbit longitudinal colonic muscle was characterized using the patch clamp technique. 2. In the cell-attached recording mode, when pipette and bath solutions contained equal [K+] (126 mM), the Ca2(+)-activated K+ channels showed a linear current-voltage relationship (between -50 mV and 50 mV) with a slope conductance of 210 +/- 35 pS (n = 12). Reversal potential measurements indicated that the channel was highly selective for K+ over Na+ (PK/PNa = 110). 3. Channels were activated by depolarizing membrane voltages and cytosolic Ca2+, and in inside-out patches channel activation depended sigmoidally on voltage and [Ca2+]. The potential for half-activation at a cytosolic [Ca2+] of 5 x 10(-6) M was 0 mV. A tenfold increase in cytosolic Ca2+ resulted in a 60 mV shift of the sigmoidal voltage activation curve to more negative potentials. 4. Threshold concentrations of substance P (10(-12) M), which did not result in cell contraction, caused a prolonged activation of K+ channels. The K+ channels were observed to open in clusters: simultaneous opening of multiple channels was interrupted by complete, prolonged channel closure. 5. Lowering bath [Ca2+] to submicromolar concentrations abolished the effect of substance P. The activation of K+ channels by substance P (10(-12) M) was also inhibited by the dihydropyridine nifedipine (10(-6) M), a blocker of L-type Ca2+ channels. 6. In the whole-cell recording mode, with the pipette solution containing 126 mM-KCl, 0.77 mM-EGTA and 1 mM-ATP, depolarization from a holding potential of -70 mV elicited outward currents which increased to steady-state values. These were K+ currents as they were blocked by TEA (tetraethylammonium, 30 mM) and Ba2+ (1 mM) and were abolished when pipette K+ was replaced by Cs+. 7. The depolarization-activated outward current was not affected by lowering extracellular [Ca2+] or by the Ca2+ channel antagonists Cd2+ (200 microM), nifedipine (10(-6)-10(-5) M) or verapamil (10(-6) M). The current was greatly reduced when the EGTA concentration in the pipette solution was increased from 0.77 to 10 mM. 8. When the pipette solution contained CsCl, membrane depolarization activated inward currents. The peak inward current was identified as current through L-type Ca2+ channels based on its voltage- and time-dependent kinetics, and its modulation by dihydropyridines.(ABSTRACT TRUNCATED AT 400 WORDS)

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Selected References

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  1. Ambler S. K., Poenie M., Tsien R. Y., Taylor P. Agonist-stimulated oscillations and cycling of intracellular free calcium in individual cultured muscle cells. J Biol Chem. 1988 Feb 5;263(4):1952–1959. [PubMed] [Google Scholar]
  2. Armstrong D. L. Calcium channel regulation by calcineurin, a Ca2+-activated phosphatase in mammalian brain. Trends Neurosci. 1989 Mar;12(3):117–122. doi: 10.1016/0166-2236(89)90168-9. [DOI] [PubMed] [Google Scholar]
  3. Armstrong D., Eckert R. Voltage-activated calcium channels that must be phosphorylated to respond to membrane depolarization. Proc Natl Acad Sci U S A. 1987 Apr;84(8):2518–2522. doi: 10.1073/pnas.84.8.2518. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Barrett J. N., Magleby K. L., Pallotta B. S. Properties of single calcium-activated potassium channels in cultured rat muscle. J Physiol. 1982 Oct;331:211–230. doi: 10.1113/jphysiol.1982.sp014370. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Barthó L., Holzer P. Search for a physiological role of substance P in gastrointestinal motility. Neuroscience. 1985 Sep;16(1):1–32. doi: 10.1016/0306-4522(85)90043-0. [DOI] [PubMed] [Google Scholar]
  6. Becker P. L., Singer J. J., Walsh J. V., Jr, Fay F. S. Regulation of calcium concentration in voltage-clamped smooth muscle cells. Science. 1989 Apr 14;244(4901):211–214. doi: 10.1126/science.2704996. [DOI] [PubMed] [Google Scholar]
  7. Benham C. D., Bolton T. B., Lang R. J., Takewaki T. Calcium-activated potassium channels in single smooth muscle cells of rabbit jejunum and guinea-pig mesenteric artery. J Physiol. 1986 Feb;371:45–67. doi: 10.1113/jphysiol.1986.sp015961. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Benham C. D., Bolton T. B. Spontaneous transient outward currents in single visceral and vascular smooth muscle cells of the rabbit. J Physiol. 1986 Dec;381:385–406. doi: 10.1113/jphysiol.1986.sp016333. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Berridge M. Second messenger dualism in neuromodulation and memory. 1986 Sep 25-Oct 1Nature. 323(6086):294–295. doi: 10.1038/323294a0. [DOI] [PubMed] [Google Scholar]
  10. Bitar K. N., Bradford P., Putney J. W., Jr, Makhlouf G. M. Cytosolic calcium during contraction of isolated mammalian gastric muscle cells. Science. 1986 May 30;232(4754):1143–1145. doi: 10.1126/science.3704641. [DOI] [PubMed] [Google Scholar]
  11. Brown P. D., Loo D. D., Wright E. M. Ca2+-activated K+ channels in the apical membrane of Necturus choroid plexus. J Membr Biol. 1988 Nov;105(3):207–219. doi: 10.1007/BF01870998. [DOI] [PubMed] [Google Scholar]
  12. Cannell M. B., Berlin J. R., Lederer W. J. Effect of membrane potential changes on the calcium transient in single rat cardiac muscle cells. Science. 1987 Dec 4;238(4832):1419–1423. doi: 10.1126/science.2446391. [DOI] [PubMed] [Google Scholar]
  13. Clapp L. H., Vivaudou M. B., Walsh J. V., Jr, Singer J. J. Acetylcholine increases voltage-activated Ca2+ current in freshly dissociated smooth muscle cells. Proc Natl Acad Sci U S A. 1987 Apr;84(7):2092–2096. doi: 10.1073/pnas.84.7.2092. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. El-Sharkawy T. Y. Electrical activities of the muscle layers of the canine colon. J Physiol. 1983 Sep;342:67–83. doi: 10.1113/jphysiol.1983.sp014840. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Ewald D. A., Williams A., Levitan I. B. Modulation of single Ca2+-dependent K+-channel activity by protein phosphorylation. Nature. 1985 Jun 6;315(6019):503–506. doi: 10.1038/315503a0. [DOI] [PubMed] [Google Scholar]
  16. Ganitkevich VYa, Shuba M. F., Smirnov S. V. Saturation of calcium channels in single isolated smooth muscle cells of guinea-pig taenia caeci. J Physiol. 1988 May;399:419–436. doi: 10.1113/jphysiol.1988.sp017089. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Hosey M. M., Lazdunski M. Calcium channels: molecular pharmacology, structure and regulation. J Membr Biol. 1988 Sep;104(2):81–105. doi: 10.1007/BF01870922. [DOI] [PubMed] [Google Scholar]
  18. Huizinga J. D., Diamant N. E., El-Sharkawy T. Y. Electrical basis of contractions in the muscle layers of the pig colon. Am J Physiol. 1983 Oct;245(4):G482–G491. doi: 10.1152/ajpgi.1983.245.4.G482. [DOI] [PubMed] [Google Scholar]
  19. Koelbel C. B., Mayer E. A., Reeve J. R., Jr, Snape W. J., Jr, Patel A., Ho F. J. Involvement of substance P in noncholinergic excitation of rabbit colonic muscle. Am J Physiol. 1989 Jan;256(1 Pt 1):G246–G253. doi: 10.1152/ajpgi.1989.256.1.G246. [DOI] [PubMed] [Google Scholar]
  20. Krouse M. E., Schneider G. T., Gage P. W. A large anion-selective channel has seven conductance levels. Nature. 1986 Jan 2;319(6048):58–60. doi: 10.1038/319058a0. [DOI] [PubMed] [Google Scholar]
  21. Loo D. D., Brown P. D., Wright E. M. Ca2+-activated K+ currents in Necturus choroid plexus. J Membr Biol. 1988 Nov;105(3):221–231. doi: 10.1007/BF01870999. [DOI] [PubMed] [Google Scholar]
  22. 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]
  23. Regoli D., Drapeau G., Dion S., D'Orléans-Juste P. Pharmacological receptors for substance P and neurokinins. Life Sci. 1987 Jan 12;40(2):109–117. doi: 10.1016/0024-3205(87)90349-3. [DOI] [PubMed] [Google Scholar]
  24. Sims S. M., Vivaudou M. B., Clapp L. H., Lassignal N. L., Walsh J. V., Jr, Singer J. J. Neurotransmitter regulation of ionic channels in freshly dissociated smooth muscle cells. Ann N Y Acad Sci. 1988;527:346–359. doi: 10.1111/j.1749-6632.1988.tb26991.x. [DOI] [PubMed] [Google Scholar]
  25. Sims S. M., Walsh J. V., Jr, Singer J. J. Substance P and acetylcholine both suppress the same K+ current in dissociated smooth muscle cells. Am J Physiol. 1986 Oct;251(4 Pt 1):C580–C587. doi: 10.1152/ajpcell.1986.251.4.C580. [DOI] [PubMed] [Google Scholar]
  26. Singer J. J., Walsh J. V., Jr Characterization of calcium-activated potassium channels in single smooth muscle cells using the patch-clamp technique. Pflugers Arch. 1987 Feb;408(2):98–111. doi: 10.1007/BF00581337. [DOI] [PubMed] [Google Scholar]
  27. Ueda S., Loo D. D., Sachs G. Regulation of K+ channels in the basolateral membrane of Necturus oxyntic cells. J Membr Biol. 1987;97(1):31–41. doi: 10.1007/BF01869612. [DOI] [PubMed] [Google Scholar]
  28. Walsh J. V., Jr, Singer J. J. Voltage clamp of single freshly dissociated smooth muscle cells: current-voltage relationships for three currents. Pflugers Arch. 1981 May;390(2):207–210. doi: 10.1007/BF00590209. [DOI] [PubMed] [Google Scholar]
  29. Watson S. P., Downes C. P. Substance P induced hydrolysis of inositol phospholipids in guinea-pig ileum and rat hypothalamus. Eur J Pharmacol. 1983 Sep 30;93(3-4):245–253. doi: 10.1016/0014-2999(83)90144-9. [DOI] [PubMed] [Google Scholar]
  30. Womack M. D., MacDermott A. B., Jessell T. M. Sensory transmitters regulate intracellular calcium in dorsal horn neurons. Nature. 1988 Jul 28;334(6180):351–353. doi: 10.1038/334351a0. [DOI] [PubMed] [Google Scholar]
  31. Yoshino M., Someya T., Nishio A., Yabu H. Whole-cell and unitary Ca channel currents in mammalian intestinal smooth muscle cells: evidence for the existence of two types of Ca channels. Pflugers Arch. 1988 Feb;411(2):229–231. doi: 10.1007/BF00582322. [DOI] [PubMed] [Google Scholar]

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