The Membrane Components of Crustacean Neuromuscular Systems.

Ozeki, Masahiro; Freeman, Alan R.; Grundfest, Harry

doi:10.1085/jgp.0491335

Cited by 59 publications

(10 citation statements)

References 21 publications

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“…the iontophoretic glutamate potential) was recorded by the nearby intracellular electrode (Figure 2a). The amplitude and the timecourse of this potential were comparable to those described by Takeuchi & Takeuchi (1964) and Onodera & Takeuchi (1975) in crayfish muscle, although the latter preparation is known to be more sensitive to iontophoretically applied glutamate (Ozeki, Freeman & Grundfest, 1966). After the bath solution had been changed to one containing 0.1 mM antazoline, the amplitude of the glutamate potential was markedly reduced (Figure 2b).…”

Section: Lobster Musclefibresupporting

confidence: 72%

Antagonism by Some Antihistamines of the Amino Acid‐evoked Responses Recorded From the Lobster Muscle Fibre and the Frog Spinal Cord

Constanti

Nistri

1976

British J Pharmacology

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I The effects of some antihistamines on the lobster muscle fibre and the frog spinal cord were investigated using intracellular and extracellular recordings, respectively.2 On lobster muscle, histamine Hl-blockers reversibly antagonized responses to bath-applied glutamate, aspartate and quisqualate but not responses to y-aminobutyric acid (GABA). Iontophoretic glutamate potentials were also reduced. Histamine (up to 1 mM) had no effect on this preparation.3 The Hl-antagonists produced a small increase in muscle membrane conductance and a slight hyperpolarization. These effects were largely unchanged in a low Cl-bathing solution. Procaine (1 mM) decreased membrane conductance and did not affect responses to GABA or glutamate. 4 The H2-antagonist burimamide blocked both glutamate and GABA-evoked responses on the lobster muscle without affecting resting potential or conductance. 5 In the frog cord, bath-applied histamine produced ventral root depolarizations and dorsal root hyperpolarizations (sometimes biphasic responses). These effects were reduced by tetrodotoxin (TTX) but not by antazoline (H,-blocker) or burimamide; the latter reversibly antagonized responses to both glutamate and GABA on TTX-treated cords while antazoline was ineffective. 6 It is suggested that antihistamines can act as non-specific amino acid antagonists by interacting at the level of the receptor-coupled ionophores.

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Section: Lobster Musclefibresupporting

confidence: 72%

Antagonism by Some Antihistamines of the Amino Acid‐evoked Responses Recorded From the Lobster Muscle Fibre and the Frog Spinal Cord

Constanti

Nistri

1976

British J Pharmacology

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“…when the effective internal resistance of 672 PERMEABILITY CHANGES BY L-GLUTAMATE 673 the negative feed-back circuit was relatively high. Since the crayfish muscle membrane shows a marked anomalous rectification (Ozeki, Freeman & Grundfest, 1966;Taraskevich, 1971;Dudel, 1974;K. Onodera & A. Takeuchi, unpublished), if the effective internal resistance of the feedback circuit was high, the membrane potential-glutamate current relation may tend to be flat upon hyperpolarization, even though the synaptic membrane conductance remained constant.…”

Section: Resultsmentioning

confidence: 99%

Permeability changes produced by L‐glutamate at the excitatory post‐synaptic membrane of the crayfish muscle.

Onodera¹,

Takeuchi²

1976

The Journal of Physiology

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SUMMARY1. Permeability changes produced by L-glutamate at the neuromuscular junction of the crayfish (Cambarus clarkii) were investigated by application of the drug iontophoretically to the voltage-clamped junction and measuring the resulting 'glutamate current'.2. Reversal potentials were determined by measuring the glutamate current at different membrane potentials. They were + 39-1 + 3-6 mV (mean + s.E. of mean) in normal solution and + 16-5 + 2-0 mV in solutions made twice as hypertonic by the addition of sucrose.3. Decreasing external Na+ concentration shifted the reversal potential in the negative direction; increased Na+ in the positive direction.4. The relation between the amplitude of the glutamate current and extracellular Na+ concentration was approximately linear.5. Alteration of the external K+ or Cl-concentration did not affect the amplitude or reversal potential of glutamate current.6. In Na+-free solution the application of L-glutamate produced a small inward current at the resting potential and its amplitude was augmented by increasing the external Ca2+ concentration.7. Increasing the Ca2+ concentration in the normal Na+ media produced no appreciable effect on the reversal potential but decreased the amplitude of glutamate current.8. The results indicate that L-glutamate increases the membrane permeability mainly to Na+ and slightly to Ca2 .9. The time course of glutamate current was shorter than that of the concentration calculated from the diffusion equation and it was simulated more closely by the square of the concentration. PHY 25522

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“…Since in these experiments the amplitude of the intracellular e.j.p. was measured to determine the reversal potential, errors due to the non-linear conductance change of the muscle membrane (Ozeki et al 1966) may have occurred. To overcome these difficulties Taraskevich (1971) and Dudel (1974) recorded extracellularly the e.j.p.s with a micro-electrode placed outside the individual synaptic spots.…”

Section: Discussionmentioning

confidence: 99%

“…However, systematic investigations on the permeability properties of this junction have not yet been made, largely for technical reasons. The experimental difficulties include measurement of the reversal potential of the crustacean neuromuscular junction, because (1) the membrane resistance of the crustacean muscle shows a remarkable non-linearity when the membrane potential is changed (Ozeki, Freeman & Grundfest, 1966;Taraskevich, 1971); (2) the crustacean muscle receives a widely distributed innervation and it does not seem possible to shift the membrane potential by applying current at a single point on the muscle fibre in order to infer the reversal potential (see Burke & Ginsborg, 1956).…”

Section: Introductionmentioning

confidence: 99%

Ionic mechanism of the excitatory synaptic membrane of the crayfish neuromuscular junction.

Onodera¹,

Takeuchi²

1975

The Journal of Physiology

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1. The reversal potential for the excitatory neuromuscular junction of the crayfish (Cambarus clarkii) was measured using the voltage clamp method. The potential change was recorded with an intracellular microcapillary and the negative phase of the output of the feed‐back amplifier was connected to the stainless‐steel wire which was inserted longitudinally into the muscle fibre. 2. When the excitatory nerve was stimulated, a transient feed‐back current flowed inwardly through the membrane. This current was called the excitatory junctional current (e.j.c.). 3. Reversal potentials were determined by extrapolating the e.j.c.s measured at different membrane potentials. They were about 10‐20 mV positive with respect to the bath solution (11‐5 +/‐ 1‐2 mV, mean +/‐ S.E.). 4. The reversal potential for the iontophoretically applied glutamate was identical with that for the e.j.c. 5. In hypertonic solutions, the reversal potentials for e.j.c. and glutamate became more negative. 6. When the sodium concentration of the bath solution was decreased, the reversal potential became more negative. 7. When the chloride and potassium concentration were altered, little, if any, change was observed in the reversal potential. 8. It was concluded that the e.j.c. was carried mainly by sodium ions. Contribution of other ions, possibly calcium ions, was discussed.

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The Membrane Components of Crustacean Neuromuscular Systems.

Cited by 59 publications

References 21 publications

Antagonism by Some Antihistamines of the Amino Acid‐evoked Responses Recorded From the Lobster Muscle Fibre and the Frog Spinal Cord

Antagonism by Some Antihistamines of the Amino Acid‐evoked Responses Recorded From the Lobster Muscle Fibre and the Frog Spinal Cord

Permeability changes produced by L‐glutamate at the excitatory post‐synaptic membrane of the crayfish muscle.

Ionic mechanism of the excitatory synaptic membrane of the crayfish neuromuscular junction.

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