Excitation of mouse motoneurones by GABA-mediated primary afferent depolarization.
Observations on the reflex properties of a mouse spinal cord preparation in vitro are reported. The findings show that the synaptically evoked, GABA-mediated, discharge of action potentials in primary afferent fibres, monitored as the dorsal root reflex, may lead to the excitation of motoneurones. Subthreshold, bicuculline-sensitive increases in motoneuronal excitability, followed by prolonged inhibition, may be seen in preparations in which the delayed reflex is not seen. Thus, primary afferent depolarization may both increase motoneuronal excitability and also cause presynaptic inhibition of afferent input.
D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D051379:Mice; D008810:Mice, Inbred C57BL; D009046:Motor Neurons / Q000187:drug effects* / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D011963:Receptors, GABA-A / Q000187:drug effects; D012018:Reflex / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000502:physiology*
D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline