[Participation of the GABA B receptors in presynaptic inhibition of the spinal cord descending projections fibers in the frog Rana ridibunda].
(-)-Baclophen was found to depress in a dose-dependent and reversible way the excitatory post-synaptic potentials (EPSPS) of motor neurons and the ventral root potentials evoked by stimulation of fibres of the ipsi- and contralateral ventral columns. The (-)-baclophen depressing effect could be eliminated with saclophen. Picrotoxin eliminated the depressing effect of the GABA on the descending EPSPS. Depressing effects of (-)-baclophen and GABA upon the ventral root potentials were also shown. The data obtained in pharmacological analysis corroborate to a certain extent existence of the GABAB receptor presynaptic inhibition in descending fibres monosynaptically corrected with the spinal cord motor neurons in the frog Rana ridibunda.
Ovsepian
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SV
I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Acad. Sci., 194223, St. Petersburg, pr. M. Toreza, 44, Russia.
Veselkin
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D000200:Action Potentials / Q000502:physiology; D000818:Animals; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D066298:In Vitro Techniques; D009046:Motor Neurons / Q000502:physiology; D009412:Nerve Fibers / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009476:Neurons, Efferent / Q000502:physiology; D011895:Rana ridibunda; D018080:Receptors, GABA-B / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000502:physiology; D013569:Synapses / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018755:GABA Agonists; D018756:GABA Antagonists; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D018080:Receptors, GABA-B; D005680:gamma-Aminobutyric Acid