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. 1991 Jan;102(1):135–145. doi: 10.1111/j.1476-5381.1991.tb12144.x

Modes of hexamethonium action on acetylcholine receptor channels in frog skeletal muscle.

D J Adams 1, S Bevan 1, D A Terrar 1
PMCID: PMC1917913  PMID: 1710523

Abstract

1. The antagonism between hexamethonium and cholinoceptor agonists was investigated in frog skeletal muscle fibres with voltage-clamp techniques. Hexamethonium caused a voltage-dependent reduction in the amplitude of endplate currents. For neurally evoked endplate currents, the reduction increased e-fold with a 38 mV membrane hyperpolarization. 2. The effect of hexamethonium on the time course of endplate currents was small, and was most apparent as a slight prolongation of the decay phase at hyperpolarized potentials (more negative than -100 mV). A similar small prolongation of single channel lifetime was detected with fluctuation analysis techniques. Hexamethonium produced a voltage-dependent reduction in apparent single channel conductance as the membrane was hyperpolarized. 3. Log (concentration-response) curves for acetylcholine (ACh)-induced currents, determined either from currents accompanying ramp changes in membrane potential or from steady state currents in voltage-jump experiments, were less steep for responses in the presence of hexamethonium. This reduction in slope became more pronounced at more negative membrane potentials. Observations at +50 mV suggested that the equilibrium constant for competitive antagonism was approximately 200 microM. 4. In voltage-jump experiments with a two-microelectrode voltage clamp, the current evoked by ACh in the presence of hexamethonium differed from that recorded with ACh alone. In the presence of hexamethonium, the expected 'instantaneous' ohmic increase in membrane current in response to a hyperpolarizing step was not detected; instead a decrease in current was observed. This problem was further investigated with a vaseline-gap voltage-clamp technique which provides improved temporal resolution. With this method a rapid decrease in the ACh-induced inward current was observed with step hyperpolarizations in the presence of hexamethonium. 5. When the membrane potential was stepped back to its resting level from a more hyperpolarized potential in the presence of hexamethonium, there was a surge of ACh-induced inward current that decayed with a time constant of less than 100 microseconds. 6. The slow relaxation in the ACh-induced current that followed a voltage step recorded in the presence of hexamethonium was slower than that recorded with ACh alone. In the presence of hexamethonium the time constant of this relaxation increased e-fold for a 67 mV hyperpolarization. 7. The results are consistent with a rapid voltage-dependent block of ACh-activated channels by hexamethonium with hyperpolarization, and voltage-dependent unblock with depolarization.(ABSTRACT TRUNCATED AT 400 WORDS)

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Selected References

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  1. Adams D. J., Nonner W., Dwyer T. M., Hille B. Block of endplate channels by permeant cations in frog skeletal muscle. J Gen Physiol. 1981 Dec;78(6):593–615. doi: 10.1085/jgp.78.6.593. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Adams P. R. Drug blockade of open end-plate channels. J Physiol. 1976 Sep;260(3):531–552. doi: 10.1113/jphysiol.1976.sp011530. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Adams P. R., Sakmann B. Decamethonium both opens and blocks endplate channels. Proc Natl Acad Sci U S A. 1978 Jun;75(6):2994–2998. doi: 10.1073/pnas.75.6.2994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Adams P. R. Voltage jump analysis of procaine action at frog end-plate. J Physiol. 1977 Jun;268(2):291–318. doi: 10.1113/jphysiol.1977.sp011858. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Adler M., Oliveira A. C., Albuquerque E. X., Mansour N. A., Eldefrawi A. T. Reaction of tetraethylammonium with the open and closed conformations of the acetylcholine receptor ionic channel complex. J Gen Physiol. 1979 Jul;74(1):129–152. doi: 10.1085/jgp.74.1.129. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Anderson C. R., Stevens C. F. Voltage clamp analysis of acetylcholine produced end-plate current fluctuations at frog neuromuscular junction. J Physiol. 1973 Dec;235(3):655–691. doi: 10.1113/jphysiol.1973.sp010410. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Armstrong D. L., Lester H. A. The kinetics of tubocurarine action and restricted diffusion within the synaptic cleft. J Physiol. 1979 Sep;294:365–386. doi: 10.1113/jphysiol.1979.sp012935. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Ascher P., Large W. A., Rang H. P. Studies on the mechanism of action of acetylcholine antagonists on rat parasympathetic ganglion cells. J Physiol. 1979 Oct;295:139–170. doi: 10.1113/jphysiol.1979.sp012958. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Blackman J. G., Gauldie R. W., Milne R. J. Interaction of competitive antagonists: the anti-curare action of hexamethonium and other antagonists at the skeletal neuromuscular junction. Br J Pharmacol. 1975 May;54(1):91–100. doi: 10.1111/j.1476-5381.1975.tb07414.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Blackman J. G., Purves R. D. Ganglionic transmission in the autonomic nervous system. N Z Med J. 1968 Mar;67(429):376–384. [PubMed] [Google Scholar]
  11. Brenner H. R., Micheroli R. On the neurotrophic control of acetylcholine receptors at frog end-plates reinnervated by the vagus nerve. J Physiol. 1985 Oct;367:387–399. doi: 10.1113/jphysiol.1985.sp015831. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Colquhoun D., Dreyer F., Sheridan R. E. The actions of tubocurarine at the frog neuromuscular junction. J Physiol. 1979 Aug;293:247–284. doi: 10.1113/jphysiol.1979.sp012888. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Colquhoun D., Hawkes A. G. Relaxation and fluctuations of membrane currents that flow through drug-operated channels. Proc R Soc Lond B Biol Sci. 1977 Nov 14;199(1135):231–262. doi: 10.1098/rspb.1977.0137. [DOI] [PubMed] [Google Scholar]
  14. Colquhoun D., Range H. P. Effects of inhibitors of the binding of iodinated alpha-bungarotoxin to acetylcholine receptors in rat muscle. Mol Pharmacol. 1976 Jul;12(4):519–535. [PubMed] [Google Scholar]
  15. Colquhoun D., Sheridan R. E. The effect of tubocurarine competition on the kinetics of agonist action on the nicotinic receptor. Br J Pharmacol. 1982 Jan;75(1):77–86. doi: 10.1111/j.1476-5381.1982.tb08759.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Colquhoun D., Sheridan R. E. The modes of action of gallamine. Proc R Soc Lond B Biol Sci. 1981 Mar 6;211(1183):181–203. doi: 10.1098/rspb.1981.0002. [DOI] [PubMed] [Google Scholar]
  17. Creese R., England J. M. Decamethonium in depolarized muscle and the effects of tubocurarine. J Physiol. 1970 Sep;210(2):345–361. doi: 10.1113/jphysiol.1970.sp009214. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Dwyer T. M., Adams D. J., Hille B. The permeability of the endplate channel to organic cations in frog muscle. J Gen Physiol. 1980 May;75(5):469–492. doi: 10.1085/jgp.75.5.469. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Feltz A., Large W. A., Trautmann A. Analysis of atropine action at the frog neutromuscular junction. J Physiol. 1977 Jul;269(1):109–130. doi: 10.1113/jphysiol.1977.sp011895. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Feltz A., Trautmann A. Desensitization at the frog neuromuscular junction: a biphasic process. J Physiol. 1982 Jan;322:257–272. doi: 10.1113/jphysiol.1982.sp014036. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Ferry C. B., Marshall A. R. An anti-curare effect of hexamethonium at the mammalian neuromuscular junction. Br J Pharmacol. 1973 Feb;47(2):353–362. doi: 10.1111/j.1476-5381.1973.tb08333.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Gandiha A., Green A. L., Marshall I. G. Some effects of hexamethonium and tetraethylammonium at a neuromuscular junction of the chicken. Eur J Pharmacol. 1972 May;18(2):174–182. doi: 10.1016/0014-2999(72)90239-7. [DOI] [PubMed] [Google Scholar]
  23. Gurney A. M., Rang H. P. The channel-blocking action of methonium compounds on rat submandibular ganglion cells. Br J Pharmacol. 1984 Jul;82(3):623–642. doi: 10.1111/j.1476-5381.1984.tb10801.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Hille B., Campbell D. T. An improved vaseline gap voltage clamp for skeletal muscle fibers. J Gen Physiol. 1976 Mar;67(3):265–293. doi: 10.1085/jgp.67.3.265. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. KATZ B., MILEDI R. THE DEVELOPMENT OF ACETYLCHOLINE SENSITIVITY IN NERVE-FREE SEGMENTS OF SKELETAL MUSCLE. J Physiol. 1964 Mar;170:389–396. doi: 10.1113/jphysiol.1964.sp007339. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. KATZ B., THESLEFF S. A study of the desensitization produced by acetylcholine at the motor end-plate. J Physiol. 1957 Aug 29;138(1):63–80. doi: 10.1113/jphysiol.1957.sp005838. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Katz B., Miledi R. A re-examination of curare action at the motor endplate. Proc R Soc Lond B Biol Sci. 1978 Dec 4;203(1151):119–133. doi: 10.1098/rspb.1978.0096. [DOI] [PubMed] [Google Scholar]
  28. Katz B., Miledi R. The effect of procaine on the action of acetylcholine at the neuromuscular junction. J Physiol. 1975 Jul;249(2):269–284. doi: 10.1113/jphysiol.1975.sp011015. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Magleby K. L., Stevens C. F. A quantitative description of end-plate currents. J Physiol. 1972 May;223(1):173–197. doi: 10.1113/jphysiol.1972.sp009840. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. McLarnon J. G., Quastel D. M. Postsynaptic effects of magnesium and calcium at the mouse neuromuscular junction. J Neurosci. 1983 Aug;3(8):1626–1633. doi: 10.1523/JNEUROSCI.03-08-01626.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Miledi R., Molenaar P. C., Polak R. L. Acetylcholinesterase activity in intact and homogenized skeletal muscle of the frog. J Physiol. 1984 Apr;349:663–686. doi: 10.1113/jphysiol.1984.sp015180. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Milne R. J., Byrne J. H. Effects of hexamethonium and decamethonium on end-plate current parameters. Mol Pharmacol. 1981 Mar;19(2):276–281. [PubMed] [Google Scholar]
  33. Neher E., Steinbach J. H. Local anaesthetics transiently block currents through single acetylcholine-receptor channels. J Physiol. 1978 Apr;277:153–176. doi: 10.1113/jphysiol.1978.sp012267. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Neher E. The charge carried by single-channel currents of rat cultured muscle cells in the presence of local anaesthetics. J Physiol. 1983 Jun;339:663–678. doi: 10.1113/jphysiol.1983.sp014741. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Neubig R. R., Cohen J. B. Permeability control by cholinergic receptors in Torpedo postsynaptic membranes: agonist dose-response relations measured at second and millisecond times. Biochemistry. 1980 Jun 10;19(12):2770–2779. doi: 10.1021/bi00553a036. [DOI] [PubMed] [Google Scholar]
  36. Ogden D. C., Colquhoun D. Ion channel block by acetylcholine, carbachol and suberyldicholine at the frog neuromuscular junction. Proc R Soc Lond B Biol Sci. 1985 Sep 23;225(1240):329–355. doi: 10.1098/rspb.1985.0065. [DOI] [PubMed] [Google Scholar]
  37. PATON W. D. M., ZAIMIS E. J. The pharmacological actions of polymethylene bistrimethyl-ammonium salts. Br J Pharmacol Chemother. 1949 Dec;4(4):381–400. doi: 10.1111/j.1476-5381.1949.tb00565.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Rang H. P., Colquhoun D., Rang H. P. The action of ganglionic blocking drugs on the synaptic responses of rat submandibular ganglion cells. Br J Pharmacol. 1982 Jan;75(1):151–168. doi: 10.1111/j.1476-5381.1982.tb08768.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Rang H. P., Ritter J. M. On the mechanism of desensitization at cholinergic receptors. Mol Pharmacol. 1970 Jul;6(4):357–382. [PubMed] [Google Scholar]
  40. Rang H. P., Rylett R. J. The interaction between hexamethonium and tubocurarine on the rat neuromuscular junction. Br J Pharmacol. 1984 Mar;81(3):519–531. doi: 10.1111/j.1476-5381.1984.tb10105.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Ruff R. L. A quantitative analysis of local anaesthetic alteration of miniature end-plate currents and end-plate current fluctuations. J Physiol. 1977 Jan;264(1):89–124. doi: 10.1113/jphysiol.1977.sp011659. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Ruff R. L. The kinetics of local anesthetic blockade of end-plate channels. Biophys J. 1982 Mar;37(3):625–631. [PMC free article] [PubMed] [Google Scholar]
  43. Sine S. M., Taylor P. Local anesthetics and histrionicotoxin are allosteric inhibitors of the acetylcholine receptor. Studies of clonal muscle cells. J Biol Chem. 1982 Jul 25;257(14):8106–8104. [PubMed] [Google Scholar]
  44. Skok V. I., Selyanko A. A., Derkach V. A. Channel-blocking activity is a possible mechanism for a selective ganglionic blockade. Pflugers Arch. 1983 Jul;398(2):169–171. doi: 10.1007/BF00581067. [DOI] [PubMed] [Google Scholar]
  45. Takeda K., Gage P. W., Barry P. H. Effects of divalent cations on toad end-plate channels. J Membr Biol. 1982;64(1-2):55–66. doi: 10.1007/BF01870768. [DOI] [PubMed] [Google Scholar]
  46. Takeda K., Trautmann A. A patch-clamp study of the partial agonist actions of tubocurarine on rat myotubes. J Physiol. 1984 Apr;349:353–374. doi: 10.1113/jphysiol.1984.sp015160. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Terrar D. A. Effects of dithiothreitol on end-plate currents. J Physiol. 1978 Mar;276:403–417. doi: 10.1113/jphysiol.1978.sp012243. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Terrar D. A. Influence of SKF-525A congeners, strophanthidin and tissue-culture media on desensitization in frog skeletal muscle. Br J Pharmacol. 1974 Jun;51(2):259–268. doi: 10.1111/j.1476-5381.1974.tb09656.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Weiland G., Taylor P. Ligand specificity of state transitions in the cholinergic receptor: behavior of agonists and antagonists. Mol Pharmacol. 1979 Mar;15(2):197–212. [PubMed] [Google Scholar]

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