Archives of Pharmacal Research

, Volume 33, Issue 3, pp 479–489 | Cite as

Phentolamine inhibits the pacemaker activity of mouse interstitial cells of Cajal by activating ATP-sensitive K+ channels

  • Seung Whan Ahn
  • Sang Hun Kim
  • Jin Ho Kim
  • Seok Choi
  • Cheol Ho Yeum
  • Hee Wook Wie
  • Jae Myeong Sun
  • Insuk So
  • Jae Yeoul JunEmail author


The aim of this study was to clarify if phentolamine has proven effects on the pacemaker activities of interstitial cells of Cajal (ICC) from the mouse small intestine involving the ATPsensitive K+ channels and adrenergic receptor. The actions of phentolamine on pacemaker activities were investigated using whole-cell patch-clamp technique and intracellular Ca2+ analysis at 30°C in cultured mouse intestinal ICC. ICC generated spontaneous pacemaker currents at a holding potential of −70 mV. Treatment with phentolamine reduced the frequency and amplitude of the pacemaker currents and increased the resting outward currents. Moreover, under current clamping (I = 0), phentolamine hyperpolarized the ICC membrane and decreased the amplitude of the pacemaker potentials. We also observed that phentolamine inhibited spontaneous [Ca2+]i oscillations in ICC. The alpha-adrenergic drugs prazosin, yohimbine, methoxamine, and clonidine had no effect on ICC intestinal pacemaker activity and did not block phentolamine-induced effects. Phentolamine-induced effects on the pacemaker currents and the pacemaker potentials were significantly inhibited by ATP sensitive K+ channel blocker glibenclamide, but not by TEA, apamin, or 4-aminopyridine. In addition, the NO synthase inhibitor, L-NAME and the guanylate cyclase inhibitor, ODQ were incapable of blocking the phentolamine-induced effects. These results demonstrate that phentolamine regulates the pacemaker activity of ICC via ATP-sensitive K+ channel activation. Phentolamine could act through an adrenergic receptor- and also through NO-independent mechanism that involves intracellular Ca2+ signaling.

Key words

Interstitial cells of Cajal Pacemaker activities Phentolamine ATP-sensitive K+ channels 


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  1. Brayden, J. E., Clinical roles of KATP channels in vascular smooth muscle. Clin. Exp. Pharmacol. Physiol., 29, 312–316 (2002).CrossRefPubMedGoogle Scholar
  2. Choi, S., Chang, I. Y., Yeum, C. H., You, H. J., Park, J. S., Jeong, H. S., So, I., Kim, K. W., and Jun, J. Y., Activating of ATP-dependent K+ channels comprised of Kir 6.2 and SUR2B by PGE2 through EP2 receptor in cultured interstitial cells of Cajal from murine small intestine. Cell. Physiol. Biochem., 18, 187–198 (2006).CrossRefPubMedGoogle Scholar
  3. Deka, D. K. and Brading, A. F., Nitric oxide activates glibenclamide-sensitive K+ channels in urinary bladder myocytes through a c-GMP-dependent mechanism. Eur. J. Pharmacol., 492, 13–19 (2004).CrossRefPubMedGoogle Scholar
  4. Dunne, M. J., Block of ATP-regulated potassium channels by phentolamine and other alpha-adrenoceptor antagonists. Br. J. Pharmacol., 103, 1847–1850 (1991).PubMedGoogle Scholar
  5. Epperson, A., Hatton, W. J., Callaghan, B., Doherty, P., Walker, R. L., Sanders, K. M., Ward, S. M., and Horowitz, B., Molecular components expressed in cultured and freshly isolated interstitial cells of Cajal. Am. J. Physiol., Cell Physiol., 279, C529–C539 (2000).PubMedGoogle Scholar
  6. Hoffmann, B. B. and Lefkowitz, R. J., The pharmacological basis of therapeutics. Pergamon Press, New York, Chapter 10, (1991).Google Scholar
  7. Hoy, M., Bokvist, K., Xiao-Gang, W., Hansen, J., Juhl, K., Berggren, P. O., Buschard, K., and Gromada, J., Phentolamine inhibits exocytosis of glucagons by Gi2 proteindependent activation of calcineurin in rat pancreatic α-cells. J. Biol. Chem., 276, 924–930 (2001).CrossRefPubMedGoogle Scholar
  8. Huizinga, J. D., Thunberg, L., Kluppel, M., Malysz, J., Mikkelsen, H. B., and Bernstein, A., W/kit gene required for interstitial cells of Cajal for intestinal pacemaker activity. Nature, 373, 347–349 (1995).CrossRefPubMedGoogle Scholar
  9. Jonas, J. C., Plant, T. D., and Henquin, J. C., Imidazoline antagonists of α2-adrenoceptors increase insulin release in vitro by inhibiting ATP-sensitive K+ channels in pancreatic β-cells. Br. J. Pharmacol., 107, 8–14 (1992).PubMedGoogle Scholar
  10. Jun, J. Y., Kong, I. D., Koh, S. D., Wang, X. U., Perrino, B. A., Ward, S. M., and Sanders, K. M., Regulation of ATP-sensitive K+ channels by protein kinase C in murine colonic myocytes. Am. J. Physiol., Cell Physiol., 281, C857–C864 (2001).PubMedGoogle Scholar
  11. Jun, J. Y., Choi, S., Yeum, C. H., Chang, I. Y., Park, C. K., Kim, M. Y., Kong, I. D., So, I., Kim, K. W., and You, H. J., Noradrenaline inhibits pacemaker currents through stimulation of beta 1-drenoceptors in cultured interstitial cells of Cajal from murine small intestine. Br. J. Pharmacol., 141, 670–677 (2004).CrossRefPubMedGoogle Scholar
  12. Jun, J. Y., Choi, S., Chang, I. Y., Yoon, C. K., Jeong, H. G., Kong, I. D., So, I., Kim, K. W., and You, H. J., Deoxycholic acid inhibits pacemaker currents by activating ATP-dependent K+ channels through prostaglandin E2 in interstitial cells of Cajal from the murine small intestine. Br. J. Pharmacol., 144, 242–251 (2005).CrossRefPubMedGoogle Scholar
  13. Kito, Y., Ward, S. M., and Sanders, K. M., Pacemaker potentials generated by interstitial cells of Cajal in the murine intestine. Am. J. Physiol., 288, C710–C720 (2005).CrossRefGoogle Scholar
  14. Kubo, M., Quayle, J. M., and Standen, N. B., Angiotensin II inhibition of ATP-sensitive K+ currents in rat arterial smooth muscle cells through protein kinase C. J. Physiol., 503, 489–496 (1997).CrossRefPubMedGoogle Scholar
  15. Mannhold, R., KATP channel openers: Structure-activity relationships and therapeutic potential. Med. Res. Rev., 24, 213–266 (2004).CrossRefPubMedGoogle Scholar
  16. Murphy, M. E. and Brayden, J. E., Nitric oxide hyperpolarizes rabbit mesenteric arteries via ATP-sensitive potassium channels. J. Physiol., 486, 47–58 (1995).PubMedGoogle Scholar
  17. Park, C. G., Kim, M. Y., Kim, J. S., Choi, S., Yeum, C. H., Parajuli, S. P., Park, J. S., Jeong, H. S., So, I., Kim, K. W., and Jun, J. Y., Inhibition of pacemaker currents by nitric oxide via activation of ATP-sensitive K+ channels in cultured interstitial cells of Cajal from mouse small intestine. Naunyn Schmiedebergs Arch. Pharmacol., 376, 175–184 (2007).CrossRefPubMedGoogle Scholar
  18. Plant, T. D. and Henquin, J. C., Phentolamine and yohimbine inhibit ATP-sensitive K+ channels in mouse pancreatic β-cells. Br. J. Pharmacol., 101, 115–120 (1990).PubMedGoogle Scholar
  19. Plant, T. D., Jonas, J. C., and Henquin, J. C., Clonidine inhibits ATP-sensitive K+ channels in mouse pancreatic β-cells. Br. J. Pharmacol., 104, 385–390 (1991).PubMedGoogle Scholar
  20. Proks, P. and Ashcroft, F. M., Phentolamine block of KATP channels is mediated by Kir 6.2. Proc. Natl. Acad. Sci. USA, 94, 11716–11720 (1997).CrossRefPubMedGoogle Scholar
  21. Quayle, J. M., Bonev, A. D., Brayden, J. E., and Nelson, M. T., Calcitonin gene-related peptide activated ATP-sensitive K+ currents in rabbit arterial smooth muscle via protein kinase A. J. Physiol., 475, 9–13 (1994).PubMedGoogle Scholar
  22. Rodrigo, G. C. and Standen, N. G., ATP-sensitive potassium channels. Curr. Pharm. Des., 11, 1915–1940 (2005).CrossRefPubMedGoogle Scholar
  23. Rustenbeck, I., Kowalewski, R., Herrmann, C., Dickel, C., Ratzka, P., and Hasselblatt, A., Effects of imidazoline compounds on cytoplasmic Ca2+ concentration and ATPsensitive K+ channels in pancreatic β-cells. Exp. Clin. Endocrinol. Diabetes, 103, 42–45 (1995.).CrossRefPubMedGoogle Scholar
  24. Sanders, K. M., Koh, S. D., and Ward, S. M., Interstitial cells of Cajal as pacemakers in the gastrointestinal tract. Annu. Rev. Physiol., 68, 307–343 (2006).CrossRefPubMedGoogle Scholar
  25. Schwietert, R., Wilhelm, D., Wilffert, B., and Van Zwieten, P. A., The effect of some alpha-adrenoceptor antagonists on spontaneous myogenic activity in the rat portal vein and the putative involvement of ATP-sensitive K+ channels. Eur. J. Pharmacol., 211, 87–95 (1992).CrossRefPubMedGoogle Scholar
  26. Shepherd, R. M., Hashmi, M. N., Kane C., Squires, P. E., and Dunne, M. J., Elevation of cytosolic calcium by imidazolines in mouse islets of Langerhans: implications for stimulus-response coupling of insulin release. Br. J. Pharmacol., 119, 911–916 (1996).PubMedGoogle Scholar
  27. Silva, L. F. G., Nascimento, N. R., Fonteles, M. C., de Nucci, G., Moraes, M. E., Vasconcelos, P. R., and Moraes, M. O., Phentolamine relaxes human corpus cavernosum by a nonadrenergic mechanism activating ATP-sensitive K+ channel. Int. J. Impot. Res., 17, 27–32 (2005).CrossRefPubMedGoogle Scholar
  28. Small, R. C., Berry, J. L., and Foster, R. W., Potassium channel opening drugs and the airways. Braz. J. Med. Biol. Res., 25, 983–998 (1992).PubMedGoogle Scholar
  29. Suzuki, H., Takano, H., Yamamoto, Y., Komuro, T., Saito, M., Kato, K., and Mikoshiba, K., Properties of gastric smooth muscles obtained from mice which lack inositol triphosphate receptor. J. Physiol., 525, 105–111 (2000).CrossRefPubMedGoogle Scholar
  30. Vemulapalli, S. and Kurowski, S., Phentolamine mesylate relaxes rabbit corpus cavernosum by a nonadrenergic, noncholinergic mechanism. Fundam. Clin. Pharmacol., 15, 1–7 (2001).CrossRefPubMedGoogle Scholar
  31. Ward, S. M., Burns, A. J., Torihashi, S., and Sanders, K. M., Mutation of the proto-oncogene c-kit blocks development of interstitial cells and electrical rhythmicity in murine intestine. J. Physiol., 480, 91–97 (1994).PubMedGoogle Scholar
  32. Ward, S. M. and Sanders, K. M., Involvement of intramus cular interstitial cells of Cajal in neuroeffector transmission in the gastrointestinal tract. J. Physiol., 576, 675–682 (2006).CrossRefPubMedGoogle Scholar
  33. Wilde, A. A., Veldkamp, M. W., van Ginneken, A. C., and Opthof, T., Phentolamine blocks ATP sensitive potassium channels in cardiac ventricular cells. Cardiovasc. Res., 28, 847–850 (1994).CrossRefPubMedGoogle Scholar
  34. Zhang, L., Bonev, A. D., Mawe, G. M., and Nelson, M. T., Protein kinase A mediates activation of ATP-sensitive K+ currents by CGRP in gallbladder smooth muscle. Am. J. Physiol., 267, G494–G499 (1994).PubMedGoogle Scholar

Copyright information

© The Pharmaceutical Society of Korea and Springer Netherlands 2010

Authors and Affiliations

  • Seung Whan Ahn
    • 1
  • Sang Hun Kim
    • 2
  • Jin Ho Kim
    • 1
  • Seok Choi
    • 3
  • Cheol Ho Yeum
    • 3
  • Hee Wook Wie
    • 3
  • Jae Myeong Sun
    • 3
  • Insuk So
    • 4
  • Jae Yeoul Jun
    • 3
    • 5
    Email author
  1. 1.Department of Neurology, College of MedicineChosun UniversityGwangjuKorea
  2. 2.Department of Anesthesiology, College of MedicineChosun UniversityGwangjuKorea
  3. 3.Department of Physiology, College of MedicineChosun UniversityGwangjuKorea
  4. 4.Department of Physiology and Biophysics, College of MedicineSeoul National UniversitySeoulKorea
  5. 5.Department of Physiology, College of MedicineChosun UniversityGwangjuKorea

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