The Effect of Tea on the Electrical Activities of Spinal Motoneurons

Washizu, Yoshiaki

doi:10.2170/jjphysiol.9.311

Cited by 20 publications

(10 citation statements)

References 13 publications

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“…In agreement with previous studies (Bonnet & Bremer, 1952;Phillis & Tebecis, 1967) the present results indicate that atropine can induce convulsant activity in the spinal cord, but in concentrations greater than 10-3 M, it tends to suppress ongoing activity. It is quite possible that in high concentrations the local anaesthetic action of atropine (Curtis & Phillis, 1961) (Washizu, 1959;Grinnell, 1970) and enhanced transmitter release (Koketsu, 1958;Payton & Shand, 1966). This property could account for some of the observed central excitatory effects of these two compounds.…”

Section: Discussionmentioning

confidence: 99%

THE ACTION OF ACETYLCHOLINE ANTAGONISTS ON AMINO ACID RESPONSES IN THE FROG SPINAL CORD in vitro

NICOLL

1975

British J Pharmacology

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I The isolated hemisected frog spinal cord has been used to study the action of acetylcholine antagonists on amino acid responses by means of sucrose gap recording. 2 Primary afferents and motoneurones were shown to contain few, if any, cholinoceptors, since acetylcholine and carbachol responses were essentially abolished when synaptic transmission was blocked with magnesium ions or when action potentials were blocked by tetrodotoxin.3 Curare antagonized the y-aminobutyric acid (GABA) and ,B-alanine depolarizations of primary afferents and the hyperpolarizing action of these amino acids on motoneurones. Nicotine also antagonized 3-alanine depolarizations and to a small extent GABA depolarizations of primary afferents. These actions are similar to but weaker than those obtained previously with picrotoxin. 4 Atropine selectively antagonized 3-alanine depolarizations of primary afferents and blocked ,B-alanine and glycine hyperpolarizations of motoneurones. GABA responses were entirely resistant to the action of atropine. These actions are similar to but 50 times weaker than those obtained previously with strychnine. 5 Dihydro-,B-erythroidine, tetraethylammonium, and gallamine were entirely ineffective in antagonizing amino acid responses. Since these agents are known to block the dorsal root potential elicited by ventral root stimulation but have no effect on the amino acid responses of primary afferents, it is evident that a cholinergic step is involved in this pathway.

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Section: Discussionmentioning

confidence: 99%

THE ACTION OF ACETYLCHOLINE ANTAGONISTS ON AMINO ACID RESPONSES IN THE FROG SPINAL CORD in vitro

NICOLL

1975

British J Pharmacology

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“…Applied externally in high concentrations, it has been shown to enhance reflex activity (Furukawa, 1955) and greatly prolong motoneurone action potentials in the isolated toad spinal cord, without depolarizing the cells or significantly changing the resting membrane resistance (Washizu, 1959). Gallamine mimics TEA in enhancing orthodromic reflex activity in the isolated frog cord (Pixner, 1967) and in enhancing activity and causing repetitive firing in mammalian central neurons (Salmoiraghi & Steiner, 1963;Curtis, Ryall & Watkins, 1966;Halpern & Black, 1967).…”

Section: Discussionmentioning

confidence: 99%

“…It is well known that both strychnine and TEA (in large concentrations, extracellularly) cause the cell to fire in multiple-spike bursts. In extreme cases the initial spike in the burst does not repolarize, but instead is prolonged in a long plateau which continues to generate a train of action potentials in the cell's axon (Washizu, 1959).…”

Section: Discussionmentioning

confidence: 99%

“…The isolated frog spinal cord has proved a useful preparation for the study of central synaptic interactions (Washizu, 1959(Washizu, , 1960Kiraly & Phillis, 1961;Katz & Miledi, 1963;Kubota & Brookhart, 1963;Grinnell, 1966;Meij, Holemans & Meyer, 1968;Meij & Holemans, 1969). In this preparation, short-latency interaction between motoneurones has been described and evidence presented that the interaction is 'electrical', rather than mediated by chemical synapses (Grinnell, 1966).…”

Section: Introductionmentioning

confidence: 99%

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Electrical interaction between antidromically stimulated frog motoneurones and dorsal root afferents: enhancement by gallamine and TEA

Grinnell¹

1970

The Journal of Physiology

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“…TEA (10-3 g/ml.) repolarized the membrane (-48-2 + 2-4 mV) and increased the membrane resistance Koketsu, 1958;Hagiwara & Saito, 1959;Washizu, 1959;Armstrong & Birrstock, 1965;Nakajima, 1966;Schmidt & Stampfli, 1966;Koppenhdfer, 1967;Hille, 1967; Kusano, Livengood & Werman, 1967a, b;Bergmann, Nonner & Stampfli, 1968;Katz & Miledi, 1969; see also the review of Shanes, 1958). Many of the above investigators led to the general conclusion that TEA was a depressant of the K-activation mechanism, i.e.…”

mentioning

confidence: 97%

Effects of tetraethylammonium chloride on the membrane activity of guinea‐pig stomach smooth muscle

Ito¹,

Kuriyama²,

Sakamoto³

1970

The Journal of Physiology

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SUMMARY1. The effects of tetraethylammonium (TEA) on the membrane activity of the antral circular muscle of the guinea-pig stomach were investigated with micro-electrode and double sucrose gap methods.2. In a concentration of 1-1 5 x 10-3 g/ml. (3-5 mM), the membrane potential was not influenced; the membrane resistance measured by inward current pulses remained the same but the rectifying property of the membrane was suppressed.3. TEA (1-1.5 x 1O-3 g/ml.) enhanced the spike amplitude markedly even from fibres which generated graded responses.4. TEA (1-1.5 x 10-3 g/ml.) did not increase the maximum rate of rise of the spike but decreased the maximum rate of fall of the spike markedly.5. In Na-free (Tris or sucrose) solution, in K-deficient and excess-K solutions, TEA (1-1 5 x 10-g/mJ.) suppressed the rectifying property of the membrane and enhanced the spike amplitude. 6. Atropine (10-6 g/ml.) had no effect on the enhancement of the spike amplitude produced by TEA.7. The minimum concentration of Ca ions required for the effect of TEA on the spike amplitude was one fifth of the normal concentration. TEA also enhanced the spike amplitude in Sr-Krebs.8. The possible role of TEA on the membrane activity is considered to be due to suppression of the K conductance when the membrane is depolarized. Alternative possible roles of TEA on the spike amplitude are also discussed.

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The Effect of Tea on the Electrical Activities of Spinal Motoneurons

Cited by 20 publications

References 13 publications

THE ACTION OF ACETYLCHOLINE ANTAGONISTS ON AMINO ACID RESPONSES IN THE FROG SPINAL CORD in vitro

THE ACTION OF ACETYLCHOLINE ANTAGONISTS ON AMINO ACID RESPONSES IN THE FROG SPINAL CORD in vitro

Electrical interaction between antidromically stimulated frog motoneurones and dorsal root afferents: enhancement by gallamine and TEA

Effects of tetraethylammonium chloride on the membrane activity of guinea‐pig stomach smooth muscle

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