Summary
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1.
The mode of action of the cholinergic antagonist hexamethonium on the excitatory responses of voltage-clampedAplysia neurons to acetylcholine (ACh) has been examined by voltage- and concentration-jump relaxation analysis.
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2.
At steady-state concentrations of ACh hyperpolarizing command steps induced inward current relaxations to a new steady-state level (I ss). The time constants of these inward relaxations, τf, which approximate the mean single-channel lifetime, were increased both by increasing the membrane potential and by lowering the bath temperature (Q 10 = 3) but were not affected by increasing the ACh concentration over the dose range employed.
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3.
In the presence of hexamethonium hyperpolarizing command steps produced biphasic relaxations of the agonist-induced current. τf was reduced in a voltagedependent manner, the degree of reduction increasing with hyperpolarization.
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4.
Slow, inverse relaxations were also triggered in the presence of hexamethonium. The time constant of this relaxation was reduced by increasing membrane potential and hexamethonium concentration.
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5.
Both the estimated association (k f = 5 × 104 M −1. sec−1) and the estimated dissociation (k b = 0.24–0.29 sec−1) rate constants derived from a three-state sequential model for block by hexamethonium were independent of the membrane potential. Similar rate constants were estimated from experiments with the concentration-jump technique, which were also independent of the membrane potential over the range - 50 to - 110 mV.
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It is suggested that the voltage-dependent actions of hexamethonium may originate either from an alteration of the channel opening and closing rate constants through an allosteric interaction with the ACh receptor, rather than through an influence of the transmembrane electric field on the rate of drug binding, or through a fast reaction which is rate-limited by voltage-independent diffusion.
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References
Adams, P. R. (1976a). Drug blockade of open end-plate channels.J. Physiol. (Lond.)260531–552.
Adams, P. R. (1976b). Voltage dependence of agonist responses at voltage-clamped frog endplates.Pflugers Arch. 361145–151.
Adams, P. R. (1981). Acetylcholine receptor kinetics.J. Membrane Biol. 58161–174.
Adams, P. R., and Feltz, A. (1977). Interaction of a fluorescent probe with acetylcholine-activated synaptic membrane.Nature 269609–611.
Adams, P. R., and Feltz, A. (1980a). Quinacrine (mepacrine) action at frog end-plate.J. Physiol. (Lond.)306261–281.
Adams, P. R., and Feltz, A. (1980b). End-plate channel opening and the kinetics of quinacrine (mepacrine) block.J. Physiol. (Lond.)306283–306.
Albuquerque, E. X., Adler, M., Spivak, C. E., and Aquayo, L. (1980). Mechanism of nicotinic channel activation and blockade.Ann. N.Y. Acad. Sci. 358204–238.
Anderson, C. R., and Stevens, C. F. (1973). Voltage clamp analysis of acetylcholine produced end-plate current fluctuations at frog neuromuscular junction.J. Physiol. (Lond.)235655–691.
Anderson, O. A. (1983). Ion movements through gramacidin A channels. Single channel measurements at very high potentials.Biophys. J. 41119–134.
Ascher, P., Marty, A., and Neild, T. O. (1978a). Lifetime and elementary conductance of the channels mediating the excitatory effects of acetylcholine inAplysia neurones.J. Physiol. (Lond.)278177–206.
Ascher, P., Marty, A., and Neild, T. O. (1978b). The mode of action of antagonists of the excitatory response to acetylcholine inAplysia neurones.J. Physiol. (Lond.)278207–235.
Ascher, P., Large, W. A., and Rang, H. P. (1979). Studies on the mechanism of action of acetylcholine antagonists on rat parasympathetic ganglion cells.J. Physiol. (Lond.)295139–170.
Auerbach, A. (1983). Kinetics of nicotinic ion channel blockade.Neurosci. Abstr. 91137.
Auerbach, A., and Sachs, F. (1984). Patch clamp studies of single ionic channels.Annu. Rev. Biophys. Bioeng. 13269–302.
Bregestovski, P. D., and Iljin, V. I. (1980). Effect of calcium antagonist D-600 on the postsynaptic membrane.J. Physiol. (Paris) 76515–522.
Bregestovski, P. D., Miledi, R., and Parker, I. (1980). Blocking of frog endplate channels by the organic calcium antagonist D-600.Proc. R. Soc. Lond. B 21115–24.
Brett, R. S., Dilger, J. P., and Adams, P. R. (1984). Improved “concentration clamp” for use with membrane patches.Neurosci. Abstr. 10241.
Clapham, D. E., and Neher, E. (1984). Substance P reduces acetylcholine-induced currents in isolated bovine chromaffin cells.J. Physiol. (Lond.)347255–277.
Colquhoun, D. (1981). How fast do drugs work? InTowards Understanding Receptors (Lamble, J. W., Ed.), Elsevier/North-Holland, Amsterdam, pp. 16–27.
Colquhoun, D., and Hawkes, A. G. (1977). Relaxation and fluctuations of membrane currents that flow through drug-operated channels.Proc. R. Soc. Lond. B 199231–262.
Colquhoun, D., and Sheridan, R. E. (1982). The effect of tubocurarine competition on the kinetics of agonist action on the nicotinic receptor.Br. J. Pharmacol. 7577–86.
Colquhoun, D., Dreyer, F., and Sheridan, R. E. (1979). The actions of tubocurarine at the frog neuromuscular junction.J. Physiol. (Lond.)293247–284.
Dilger, J. P., and Adams, P. R. (1984). Rapid perfusion of excised patches—activation and desensitization of nicotinic receptor channels.Biophys. J. 45:386a.
Dreyer, F., Peper, K., Sterz, R., Bradley, R. J., and Muller, K.-D. (1978). Drug-receptor interaction atthe frog neuromuscular junction. InThe Cholinergic Synapse, Progress in Brain Research, Vol. 49 (Tucek, S., Ed.), Elsevier, Amsterdam, pp. 214–223.
Feltz, A., Large, W. A., and Trautmann, A. (1977). Analysis of atropine action at the frog neuromuscular junction.J. Physiol. (Lond.)269109–130.
Frazier, W. T., Kandel, E. R., Kupferman, I., Waziri, R., and Coggeshall, R. E. (1967). Morphological and functional properties of identified neurons in the abdominal ganglion ofAplysia californica.J. Neurophysiol. 301288–1351.
Gurney, A. M., and Rang, H. P. (1984). The channel-blocking action of methonium compounds on rat submandibular ganglion cells.Br. J. Pharmacol. 82623–642.
Heidmann, T., Oswald, R. E., and Changeux, J.-P. (1983). Multiple sites of action for noncompetitive blockers on acetylcholine receptor rich membrane fragments fromTorpedo marmorata.Biochemistry 223112–3127.
Hille, B. (1977). Local anesthetics: Hydrophilic and hydrophobic pathways for the drug-receptor reaction.J. Gen. Physiol. 69497–515.
Katz, B., and Miledi, R. (1972). The statistical nature of the acetylcholine potential and its molecular components.J. Physiol. (Lond.)224665–699.
Kehoe, J.-S. (1972). Three acetylcholine receptors inAplysia neurones.J. Physiol. (Lond.)225115–146.
Krishtal, O. A., and Pidoplichko, V. I. (1980). A receptor for protons in the nerve cell membrane.Neuroscience 52325–2327.
Krouse, M. E., Lester, H. A., Erlanger, B. F., and Wassermann, N. H. (1984). The measurement of the rate constants for a competitive antagonist of the nicotinic acetylcholine receptor.Biophys. J. 45:387a.
Lambert, J. J., Durant, N. N., and Henderson, E. G. (1983). Drug-induced modification of ionic conductance at the neuromuscular junction.Annu. Rev. Pharmacol. Toxicol. 23505–539.
Marty, A. (1978). Noise and relaxation studies of acetylcholine induced currents in the presence of procaine.J. Physiol. (Lond.)278237–250.
Marty, A., Neild, T. O., and Ascher, P. (1976). Voltage sensitivity of acetylcholine currents inAplysia neurones in the presence of curare.Nature 261501–503.
Miledi, R., and Parker, I. (1980). Blocking of acetylcholine-induced channels by extracellular or intracellular application of D-600.Proc. R. Soc. Lond. B 211143–150.
Milne, R. J., and Byrne, J. H. (1981). Effects of hexamethonium and decamethonium on end-plate current parameters.Mol. Pharmacol. 19276–281.
Neher, E. (1983). The charge carried by single-channel currents of rat cultured muscle cells in the presence of local anesthetics.J. Physiol. (Lond.)339663–678.
Neher, E., and Steinbach, J. H. (1978). Local anaesthetics transiently block currents through single acetylcholine receptor channels.J. Physiol. (Lond.)277153–176.
Ogden, D. C., Siegelbaum, S. A., and Colquhoun, D. (1981). Block of acetylcholine-activated ion channels by an uncharged local anaesthetic.Nature 289596–598.
Peper, K., Bradley, R. J., and Dreyer, F. (1982). The acetylcholine receptor at the neuromuscular junction.Physiol. Rev. 621271–1340.
Possier, P., Baux, G., and Tauc, L. (1983). Possible role of acetylcholinesterase in regulation of postsynaptic receptor efficacy at a central inhibitory synapse ofAplysia.Nature 301710–712.
Rang, H. P. (1975). Acetylcholine receptors.Q. Rev. Biophys. 7283–399.
Sakmann, B., and Adams, P. R. (1979). Biophysical aspects of agonist action at frog endplate. InAdvances in Pharmacology and Therapeutics, Vol. 1, Receptors (Jacob, J., Ed.), Pergamon, Oxford, pp. 81–90.
Sattelle, D. B., and David, J. A. (1983). Voltage-dependent block by histrionicotoxin of the acetylcholineinduced current in an insect motoneurone cell body.Neurosci. Lett. 4337–41.
Sheridan, R. E., and Lester, H. A. (1975). Relaxation measurements on the acetylcholine receptor.Proc. Natl. Acad. Sci. USA 723496–3500.
Sheridan, R. E., and Lester, H. A. (1977). Rates and equilibria at the acetylcholine receptor ofElectrophorus electroplaques. A study of neurally evoked postsynaptic currents and of voltage-jump relaxations.J. Gen. Physiol. 70187–219.
Simmons, L. (1983). Preliminary characterization of excitatory acetylcholine receptors inAplysia using the single channel recording technique.Neurosci. Abstr. 9457.
Sine, S. M., and Steinbach, J. H. (1984). Agonists block currents through acetylcholine receptor channels.Biophys. J. 46277–284.
Slater, N. T., and Carpenter, D. O. (1982). Blockade of acetylcholine-induced inward current inAplysia neurons by strychnine and desipramine: Effect of membrane potential.Cell. Mol. Neurobiol. 253–58.
Slater, N. T., and Carpenter, D. O. (1984). A study of the cholinolytic actions of strychnine using the technique of concentration jump relaxation analysis.Cell. Mol. Neurobiol. 4263–271.
Slater, N. T., and Carpenter, D. O. (1985). Direct effects of neostigmine on acetylcholine receptor activation and desensitization inAplysia neurones.Pflugers Arch. 403 (Suppl.):R50.
Slater, N. T., Haas, H. L., and Carpenter, D. O. (1983). Kinetics of acetylcholine-activated cation channel blockade by the calcium antagonist D-600 inAplysia neurons.Cell. Mol. Neurobiol. 3329–344.
Slater, N. T., Carpenter, D. O., Haas, H. L., and David, J. A. (1984a). Blocking kinetics at excitatory acetylcholine responses onAplysia neurons.Biophys. J. 4524–25.
Slater, N. T., Hall, A. F., and Carpenter, D. O. (1984b). Kinetic properties of cholinergic desensitization inAplysia neurons.Proc. R. Soc. Lond. B 22363–78.
Steinbach, J. H. (1980). Activation of nicotinic acetylcholine receptors. InThe Cell Surface and Neuronal Function (Cotman, C. W., Poste, G., and Nicolson, G. I., Eds.), Elsevier/North-Holland, Amsterdam, pp. 119–156.
van Ginnekin, C. A. M. (1977). Kinetics of drug-receptor interaction. InKinetics of Drug Action (van Rossum, J. M., Eds.), Springer-Verlag, Berlin, pp. 357–411.
Wachtel, R. E., and Wilson, W. A. (1983). Barbiturate effects on acetylcholine-activated channels inAplysia neurons.Mol. Pharmacol. 24449–457.
Woodhull, A. M. (1973). Ionic blockage of sodium channels in nerve.J. Gen. Physiol. 61687–708.
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Slater, N.T., David, J.A. & Carpenter, D.O. Relaxation studies on the interaction of hexamethonium with acetylcholine-receptor channels inAplysia neurons. Cell Mol Neurobiol 6, 191–212 (1986). https://doi.org/10.1007/BF00711070
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DOI: https://doi.org/10.1007/BF00711070