Springer Online Journal Archives 1860-2000
Summary The pharmacological properties of Deiters neurones were studied in anaesthetized cats, together with their inhibition by cerebellar Purkinje cells. Purkinje cell inhibition, as detected by depression of antidromic field potentials of Deiters neurones, was blocked by relatively large doses of picrotoxin administered intravenously (5–10 mg/kg). The cerebellar inhibition was also detected as a depression of the discharge of Deiters neurones excited by electrophoretic administration of DL-homocysteic acid. This inhibition was abolished or reduced by picrotoxin, but was not altered by strychnine, administered either systemically or electrophoretically. γ-Aminobutyric acid (GABA), glycine, β-alanine and imidazole acetic acid, when administered electrophoretically, also depressed the antidromic field potentials and the spike discharges of Deiters neurones. Picrotoxin antagonized the effect of GABA but not of glycine, while strychnine blocked only the action of glycine. Intracellular recording from Deiters neurones revealed that both GABA and glycine, ejected extracellularly, hyperpolarized the membrane and increased the membrane conductance. The reversal of the GABA-induced hyperpolarization was at the same potential level as that of the inhibitory postsynaptic potentials induced by cerebellar stimulation. These results are consistent with the hypothesis that the inhibitory transmitter released from Purkinje cell axons is GABA or a related substance.
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