Presynaptic inhibition at the crayfish neuromuscular junction

Dudél, J.; Kuffler, Stephen W.

doi:10.1113/jphysiol.1961.sp006646

Cited by 429 publications

(152 citation statements)

References 19 publications

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“…Materials and Methods.-Saline medium used to wash nerve-muscle preparations had the following composition: 460 mM NaCl, 15.6 mM KC1, 26 mM CaCl2, 8.3 mM MgSO4.…”

mentioning

confidence: 99%

Release of gamma-aminobutyric acid from inhibitory nerves of lobster.

Otsuka¹,

Ll²,

Hall³

et al. 1966

Proc. Natl. Acad. Sci. U.S.A.

229

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In 1957, Bazemore, Elliott, and Florey' showed that y-aminobutyric acid (GABA) blocked the discharges of crayfish stretch-receptor neurons. This finding focused attention on the possible role of GABA as an inhibitory transmitter compound. At various crustacean synapses GABA was found to mimic the effects of inhibitory (I) nerve stimulation.2-9 Furthermore, in the lobster nervous system GABA is highly concentrated in I neurons, the ratio of GABA concentrations in I and excitatory (E) axons being more than 100:1.10-12 Although this evidence is consistent with GABA being an inhibitory transmitter compound, a crucial experiment has hitherto been lacking: the demonstration that GABA is released from I-nerve terminals in response to nerve stimulation.The results of the present study show that stimulation of the I-nerve innervating various lobster muscles causes a release of GABA into the bathing fluid; the amount released is proportional to the number of stimuli applied.Materials and Methods.-Saline medium used to wash nerve-muscle preparations had the following composition: 460 mM NaCl, 15.6 mM KC1, 26 mM CaCl2, 8.3 mM MgSO4.Dowex-50W-X-2, H+ resin (100-200 mesh) was obtained from Baker Chemical Co. After fine particles were removed by repeated decantation, the resin was cycled through ammonium and hydrogen forms, and was freshly washed with 5-bed vol of 2 N hydrochloric acid and 2-bed vol of water immediately before use.Dowex-l-X2, Cl-resin (100-200 mesh) was obtained from Bio Rad Laboratories. The resin was thoroughly washed with 2 N hydrochloric acid, and then with 2 N acetic acid to convert it to the acetate form; resin columns were freshly washed with 5-bed vol of 2 N acetic acid and 5-bed vol of water immediately before use.3-H3-GABA (specific activity 5 c/mmole) was synthesized from DL-3-H3-glutamate (New England Nuclear Corp., Boston, Mass.) by decarboxylation with a bacterial glutamate decarboxylase.Nerve-muscle preparations: Opener muscles from the crusher and cutter claws of 0.5-kg lobsters (Homarus americanus) were set up as illustrated in Figure 1. The single E and I axons innervating the muscle lie in separate bundles in the carpopodite segment: these were dissected and stimulated separately with suction electrodes. The closer muscle and overlying connective tissue were carefully removed to expose the opener muscle. The opener muscles remained in situ in the exoskeleton which formed a convenient chamber for washing with saline medium. Junctional (synaptic) potentials were recorded intracellularly from muscle fibers with a glass microelectrode filled with 2 M potassium citrate. Chilled, oxygenated saline medium was pumped onto the proximal end of the muscle at a rate of approximately 2 ml/min. The perfusion medium percolated through the muscle and dripped out of the cut end of the dactyl (cleaned of internal tissue). The temperature of the effluent medium was 12-14°. I or E nerves were stimulated at frequencies of 5-20 impulses/sec for the first 15 min of the collection period.Superficial flexor muscles ...

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“…Materials and Methods.-Saline medium used to wash nerve-muscle preparations had the following composition: 460 mM NaCl, 15.6 mM KC1, 26 mM CaCl2, 8.3 mM MgSO4.…”

mentioning

confidence: 99%

Release of gamma-aminobutyric acid from inhibitory nerves of lobster.

Otsuka¹,

Ll²,

Hall³

et al. 1966

Proc. Natl. Acad. Sci. U.S.A.

229

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“…If the membrane capacitance is ignored the equivalent electrical circuit of the post-synaptic membrane of the crab neuromuscular junction is given in Figure 1 mitter, in the crayfish, is -+ 1 5 mV (Takeuchi & Onodera, 1973) while that of the inhibitory transmitter is -70 mV (Dudel & Kuffler, 1961 membrane resistance, the difference must be due to a pre-synaptic effect.…”

Section: Methodsmentioning

confidence: 99%

Some Characteristics of Pre‐ and Post‐synaptic Inhibitory Receptors at the Hermit Crab Neuromuscular Junction

Balashov

Earl

Large

1975

British J Pharmacology

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1The effects of y-aminobutyric acid (GABA), 3-guanidinopropionic acid (,BGP) and picrotoxin on the pre-and post-synaptic receptors of the hermit crab neuromuscular junction were studied quantitatively using electrophysiological techniques. Reductions in excitatory junction potential (e.j.p.) amplitude and membrane resistance were measured simultaneously from the same cells. 2 The pre-and post-synaptic receptors were activated by the same order of concentration of GABA, whereas tGP stimulated the pre-synaptic receptors at a concentration ten times lower than was required to affect the post-synaptic membrane. 3 Picrotoxin appeared to antagonize the pre-synaptic action of j3GP in a competitive manner. The affinity constants (± s.e. mean) for picrotoxin 5 x 1O-6M and 2 x 1O-4M were 6.80 (± 0.46) x 1OM 1 and 6.42 (± 1.8) x 105M-1 respectively. 4 The effect of GABA on e.j.p. amplitude also appeared to be antagonized competitively by picrotoxin whereas the post-synaptic effect was antagonized in a non-competitive manner. 5 Possible differences in the nature of the pre-and post-synaptic receptors are discussed.

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“…Indeed, GABA can yield opposite effects on transmitter release at different synapses, i.e. facilitation [12] or depression [1,5,13]. The direction of the modulation depends on presynaptic factors, including the axonal membrane chloride gradient [12] and the activation of voltage-dependent ion channels at the presynaptic terminal [14].…”

Section: Introductionmentioning

confidence: 99%

Inhibition of GABA release by presynaptic ionotropic GABA receptors in hippocampal CA3

Axmacher

Draguhn

2004

NeuroReport

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Vesicular transmitter release can be regulated by transmittergated ion channels at presynaptic axon terminals. The central inhibitory transmitter GABA acts on such presynaptic ionotropic receptors in various cells, including inhibitory interneurons. Here we report that GABA-mediated postsynaptic inhibitory currents in CA3 pyramidal cells of rat hippocampal slices are suppressed by agonists of GABA A receptors. The e¡ect is present for both stimulus-induced and miniature IPSCs, indicating a reduction in the probability of vesicular release by presynaptic, action-potential-independent mechanisms. We conclude that the release of GABA from hippocampal CA3 interneurons is regulated by a negative feedback via presynaptic ionotropic GABA autoreceptors.

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Presynaptic inhibition at the crayfish neuromuscular junction

Cited by 429 publications

References 19 publications

Release of gamma-aminobutyric acid from inhibitory nerves of lobster.

Release of gamma-aminobutyric acid from inhibitory nerves of lobster.

Some Characteristics of Pre‐ and Post‐synaptic Inhibitory Receptors at the Hermit Crab Neuromuscular Junction

Inhibition of GABA release by presynaptic ionotropic GABA receptors in hippocampal CA3

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