Abstract
The effects of intracellular application of three compounds - QX314, N-ethylguanidine and N-octylguanidine - on the acetylcholine-activated ionic channels in chick myoballs were examined. Voltage-clamped myoballs were internally perfused using the suction-pipette technique. Changes in the internal ionic environment of myoballs were demonstrated by: (1) alteration of the reversal potential for both acetylcholine-activated ionic currents and voltage-gated sodium currents in a manner predicted by the Goldman-Hodgkin-Katz equation, and (2) elimination of potassium currents after removal of intracellular and extracellular potassium. Ethylguanidine (5 mM) and octylguanidine (5 microM) blocked acetylcholine-induced currents by 83% when applied externally. QX314 (0.5 mM) and octylguanidine (100 microM) had no effect on acetylcholine-induced currents when perfused internally, although in the same cells these compounds caused marked inhibition of voltage-gated sodium currents. Ethylguanidine (10 mM) reduced acetylcholine-induced currents by approximately 20-30% after internal application. It was much less potent from inside than from outside, and the inhibition was not voltage-dependent. We conclude that the internal mouth of the acetylcholine-activated channel must be much more selective with respect to drug binding than is the external channel mouth. Internally applied ethylguanidine may penetrate into the channel beyond the selectivity filter to a drug binding site to cause block.
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Selected References
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- 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]
- Adams P. R. Acetylcholine receptor kinetics. J Membr Biol. 1981 Feb 28;58(3):161–174. doi: 10.1007/BF01870902. [DOI] [PubMed] [Google Scholar]
- 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]
- 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]
- Aguayo L. G., Pazhenchevsky B., Daly J. W., Albuquerque E. X. The ionic channel of the acetylcholine receptor. Regulation by sites outside and inside the cell membrane which are sensitive to quaternary ligands. Mol Pharmacol. 1981 Sep;20(2):345–355. [PubMed] [Google Scholar]
- Albuquerque E. X., Tsai M. C., Aronstam R. S., Eldefrawi A. T., Eldefrawi M. E. Sites of action of phencyclidine. II. Interaction with the ionic channel of the nicotinic receptor. Mol Pharmacol. 1980 Sep;18(2):167–178. [PubMed] [Google Scholar]
- Allen T., Baerwald R., Potter L. T. Postsynaptic membranes in the electric tissue of Narcine: II. A freeze-fracture study of nicotinic receptor molecules. Tissue Cell. 1977;9(4):595–608. doi: 10.1016/0040-8166(77)90029-5. [DOI] [PubMed] [Google Scholar]
- Beam K. G. A quantitative description of end-plate currents in the presence of two lidocaine derivatives. J Physiol. 1976 Jun;258(2):301–322. doi: 10.1113/jphysiol.1976.sp011421. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DEL CASTILLO L., KATZ B. A study of curare action with an electrical micromethod. Proc R Soc Lond B Biol Sci. 1957 May 7;146(924):339–356. doi: 10.1098/rspb.1957.0015. [DOI] [PubMed] [Google Scholar]
- 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]
- Farley J. M., Yeh J. Z., Watanabe S., Narahashi T. Endplate channel block by guanidine derivatives. J Gen Physiol. 1981 Mar;77(3):273–293. doi: 10.1085/jgp.77.3.273. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fischbach G. D., Lass Y. Acetylcholine noise in cultured chick myoballs: a voltage clamp analysis. J Physiol. 1978 Jul;280:515–526. doi: 10.1113/jphysiol.1978.sp012398. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heuser J. E., Salpeter S. R. Organization of acetylcholine receptors in quick-frozen, deep-etched, and rotary-replicated Torpedo postsynaptic membrane. J Cell Biol. 1979 Jul;82(1):150–173. doi: 10.1083/jcb.82.1.150. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horn R., Brodwick M. S. Acetylcholine-induced current in perfused rat myoballs. J Gen Physiol. 1980 Mar;75(3):297–321. doi: 10.1085/jgp.75.3.297. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horn R., Brodwick M. S., Dickey W. D. Asymmetry of the acetylcholine channel revealed by quaternary anesthetics. Science. 1980 Oct 10;210(4466):205–207. doi: 10.1126/science.6251552. [DOI] [PubMed] [Google Scholar]
- Horn R., Patlak J. Single channel currents from excised patches of muscle membrane. Proc Natl Acad Sci U S A. 1980 Nov;77(11):6930–6934. doi: 10.1073/pnas.77.11.6930. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kirsch G. E., Yeh J. Z., Farley J. M., Narahashi T. Interaction of n-alkylguanidines with the sodium channels of squid axon membrane. J Gen Physiol. 1980 Sep;76(3):315–335. doi: 10.1085/jgp.76.3.315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee K. S., Akaike N., Brown A. M. Properties of internally perfused, voltage-clamped, isolated nerve cell bodies. J Gen Physiol. 1978 May;71(5):489–507. doi: 10.1085/jgp.71.5.489. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee K. S., Weeks T. A., Kao R. L., Akaike N., Brown A. M. Sodium current in single heart muscle cells. Nature. 1979 Mar 15;278(5701):269–271. doi: 10.1038/278269a0. [DOI] [PubMed] [Google Scholar]
- Masukawa L. M., Albuquerque E. X. Voltage- and time-dependent action of histrionicotoxin on the endplate current of the frog muscle. J Gen Physiol. 1978 Sep;72(3):351–367. doi: 10.1085/jgp.72.3.351. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Ogden D. C., Siegelbaum S. A., Colquhoun D. Block of acetylcholine-activated ion channels by an uncharged local anaesthetic. Nature. 1981 Feb 12;289(5798):596–598. doi: 10.1038/289596a0. [DOI] [PubMed] [Google Scholar]
- Rosenbluth J. Synaptic membrane structure in Torpedo electric organ. J Neurocytol. 1975 Dec;4(6):697–712. doi: 10.1007/BF01181631. [DOI] [PubMed] [Google Scholar]
- Sigworth F. J., Neher E. Single Na+ channel currents observed in cultured rat muscle cells. Nature. 1980 Oct 2;287(5781):447–449. doi: 10.1038/287447a0. [DOI] [PubMed] [Google Scholar]
- Strichartz G. R. The inhibition of sodium currents in myelinated nerve by quaternary derivatives of lidocaine. J Gen Physiol. 1973 Jul;62(1):37–57. doi: 10.1085/jgp.62.1.37. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TAKEUCHI A., TAKEUCHI N. Active phase of frog's end-plate potential. J Neurophysiol. 1959 Jul;22(4):395–411. doi: 10.1152/jn.1959.22.4.395. [DOI] [PubMed] [Google Scholar]
- Tiedt T. N., Albuquerque E. X., Bakry N. M., Eldefrawi M. E., Eldefrawi A. T. Voltage- and time-dependent actions of piperocaine on the ion channel of the acetylcholine receptor. Mol Pharmacol. 1979 Nov;16(3):909–921. [PubMed] [Google Scholar]
- Watanabe S., Narahashi T. Cation selectivity of acetylcholine-activated ionic channel of frog endplate. J Gen Physiol. 1979 Nov;74(5):615–628. doi: 10.1085/jgp.74.5.615. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yeh J. Z. Sodium inactivation mechanism modulates QX-314 block of sodium channels in squid axons. Biophys J. 1978 Nov;24(2):569–574. doi: 10.1016/S0006-3495(78)85403-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
