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. 1959 Jul 20;42(6):1301–1323. doi: 10.1085/jgp.42.6.1301

THE ELECTROPHYSIOLOGY AND PHARMACOLOGY OF LOBSTER NEUROMUSCULAR SYNAPSES

H Grundfest 1, J P Reuben 1, W H Rickles 1
PMCID: PMC2194962  PMID: 13664927

Abstract

Effects of drugs on resting potential, membrane resistance, and excitatory and inhibitory postsynaptic potentials (e.p.s.p.'s and i.p.s.p.'s) of lobster muscle fibers were studied using intracellular microelectrodes Acetylcholine, d-tubocurarine, strychnine, and other drugs of respectively related actions on vertebrate synapses were without effects even in 1 per cent solutions (10- w/v). Gamma-aminobutyric acid (GABA) acted powerfully and nearly maximally at 10-7 to 10-6 w/v. Membrane resistance fell two- to tenfold, the resting potential usually increasing slightly. This combination of effects, which indicates activation of inhibitory synaptic membrane, was also produced by other short chain ω-amino acids and related compounds that inactivate depolarizing axodendritic synapses of cat. The conductance change, involving increased permeability to Cl-, by its clamping action on membrane potential shortened as well as decreased individual e.p.s.p.'s. Picrotoxin in low concentration (ca. 10-7 w/v) and guanidine in higher (ca. 10-3 w/v) specifically inactivate inhibitory synapses. GABA and picrotoxin are competitive antagonists. The longer chain ω-amino acids which inactivate hyperpolarizing axodendritic synapses of cat are without effect on lobster neuromuscular synapse. However, one member of this group, carnitine (β-OH-GABA betaine), activated the excitatory synapses, a decreased membrane resistance being associated with depolarzation. The pharmacological properties of lobster neuromuscular synapses and probably also of other crustacean inhibitory synapses appear to stand in a doubly inverted relation to axodendritic synapses of cat.

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Selected References

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  1. BAZEMORE A., ELLIOTT K. A., FLOREY E. Factor I and gamma-aminobutyric acid. Nature. 1956 Nov 10;178(4541):1052–1053. doi: 10.1038/1781052a0. [DOI] [PubMed] [Google Scholar]
  2. BOISTEL J., FATT P. Membrane permeability change during inhibitory transmitter action in crustacean muscle. J Physiol. 1958 Nov 10;144(1):176–191. doi: 10.1113/jphysiol.1958.sp006094. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. BRYANT S. H. Transmission in squid giant synapses: the importance of oxygen supply and the effects of drugs. J Gen Physiol. 1958 Jan 20;41(3):473–484. doi: 10.1085/jgp.41.3.473. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. ELLIOTT K. A., FLOREY E. Factor I--inhibitory factor from brain; assay; conditions in brain; simulating and antagonizing substances. J Neurochem. 1956 Dec;1(2):181–192. doi: 10.1111/j.1471-4159.1956.tb12071.x. [DOI] [PubMed] [Google Scholar]
  5. FATT P. Biophysics of junctional transmission. Physiol Rev. 1954 Oct;34(4):674–710. doi: 10.1152/physrev.1954.34.4.674. [DOI] [PubMed] [Google Scholar]
  6. FATT P., GINSBORG B. L. The production of regenerative responses in crayfish muscle fibres by the action of calcium, strontium and barium. J Physiol. 1958 Feb 17;140(2):59–60P. [PubMed] [Google Scholar]
  7. FATT P., KATZ B. The effect of inhibitory nerve impulses on a crustacean muscle fibre. J Physiol. 1953 Aug;121(2):374–389. doi: 10.1113/jphysiol.1953.sp004952. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. FATT P., KATZ B. The electrical properties of crustacean muscle fibres. J Physiol. 1953 Apr 28;120(1-2):171–204. doi: 10.1113/jphysiol.1953.sp004884. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. FURSHPAN E. J., POTTER D. D. Slow post-synaptic potentials recorded from the giant motor fibre of the crayfish. J Physiol. 1959 Mar 3;145(2):326–335. doi: 10.1113/jphysiol.1959.sp006144. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. GRUNDFEST H. An electrophysiological basis for neuropharmacology. Fed Proc. 1958 Dec;17(4):1006–1018. [PubMed] [Google Scholar]
  11. GRUNDFEST H. Electrical inexcitability of synapses and some consequences in the central nervous system. Physiol Rev. 1957 Jul;37(3):337–361. doi: 10.1152/physrev.1957.37.3.337. [DOI] [PubMed] [Google Scholar]
  12. GRUNDFEST H. General problems of drugs actions on bioelectric phenomena. Ann N Y Acad Sci. 1957 Mar 14;66(3):537–591. doi: 10.1111/j.1749-6632.1957.tb40748.x. [DOI] [PubMed] [Google Scholar]
  13. GRUNDFEST H. The mechanisms of discharge of the electric organs in relation to general and comparative electrophysiology. Prog Biophys Biophys Chem. 1957;7:1–85. [PubMed] [Google Scholar]
  14. HOYLE G., WIERSMA C. A. Coupling of membrane potential to contraction in crustacean muscles. J Physiol. 1958 Oct 31;143(3):441–453. doi: 10.1113/jphysiol.1958.sp006070. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. HOYLE G., WIERSMA C. A. Excitation at neuromuscular junctions in Crustacea. J Physiol. 1958 Oct 31;143(3):403–425. doi: 10.1113/jphysiol.1958.sp006068. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. HOYLE G., WIERSMA C. A. Inhibition at neuromuscular junctions in Crustacea. J Physiol. 1958 Oct 31;143(3):426–440. doi: 10.1113/jphysiol.1958.sp006069. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. KAO C. Y., GRUNDFEST H. Postsynaptic electrogenesis in septate giant axons. I. Earthworm median giant axon. J Neurophysiol. 1957 Nov;20(6):553–573. doi: 10.1152/jn.1957.20.6.553. [DOI] [PubMed] [Google Scholar]
  18. KUNO M. Effects of strychnine on the intracellular potentials of spinal motoneurons of the toad. Jpn J Physiol. 1957 Mar 15;7(1):42–50. doi: 10.2170/jjphysiol.7.42. [DOI] [PubMed] [Google Scholar]
  19. McLENNAN H. A comparison of some physiological properties of an inhibitory factor from brain (factor I) and of gamma-aminobutyric acid and related compounds. J Physiol. 1957 Nov 14;139(1):79–86. doi: 10.1113/jphysiol.1957.sp005876. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. PURPURA D. P., GIRADO M., GRUNDFEST H. Central synaptic effects of omega-guanidino acids and amino acid derivatives. Science. 1958 May 16;127(3307):1179–1181. doi: 10.1126/science.127.3307.1179. [DOI] [PubMed] [Google Scholar]
  21. PURPURA D. P., GIRADO M., GRUNDFEST H. Mode of action of aliphatic amino acids on cortical synaptic activity. Proc Soc Exp Biol Med. 1957 Aug-Sep;95(4):791–796. doi: 10.3181/00379727-95-23366. [DOI] [PubMed] [Google Scholar]
  22. PURPURA D. P., GIRADO M., GRUNDFEST H. Selective blockade of excitatory synapses in the cat brain by gamma-aminobutyric acid. Science. 1957 Jun 14;125(3259):1200–1202. doi: 10.1126/science.125.3259.1200-a. [DOI] [PubMed] [Google Scholar]
  23. PURPURA D. P., GIRADO M., SMITH T. G., CALLAN D. A., GRUNDFEST H. Structure-activity determinants of pharmacological effects of amino acids and related compounds on central synapses. J Neurochem. 1959 Jan;3(3):238–268. doi: 10.1111/j.1471-4159.1959.tb12630.x. [DOI] [PubMed] [Google Scholar]
  24. ROBBINS J., VAN DER KLOOT W. G. The effect of picrotoxin on peripheral inhibition in the crayfish. J Physiol. 1958 Oct 31;143(3):541–552. doi: 10.1113/jphysiol.1958.sp006076. [DOI] [PMC free article] [PubMed] [Google Scholar]

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