Evidence for a GABA-mediated cerebellar inhibition of the inferior olive in the cat.
1. Climbing fibres were activated by peripheral nerve stimulation at 'high' frequencies (greater than 3 Hz) for 15-25 s and then at 0.9 Hz for about 1 min. The high frequency activation induced a post-conditioning inhibition, lasting up to about 1 min, of climbing fibre responses recorded from the cerebellar surface. 2. Electrolytic lesions were made in the superior cerebellar peduncle (brachium conjunctivum). After the lesion, the post-conditioning inhibition was completely eliminated. 3. Injections of the GABA-receptor blocker bicuculline methiodide into the inferior olive reversibly blocked the post-conditioning inhibition. 4. The results support the hypothesis proposed by Andersson and Hesslow (1987a), that post-conditioning inhibition is mediated by a GABA-ergic interposito-olivary pathway.
Andersson
G
G
Department of Physiology and Biophysics, University of Lund, Sweden.
Garwicz
M
M
Hesslow
G
G
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D001933:Brain Stem / Q000502:physiology; D002415:Cats; D002531:Cerebellum / Q000502:physiology*; D004558:Electric Stimulation; D009847:Olivary Nucleus / Q000187:drug effects / Q000502:physiology*; D011826:Radial Nerve / Q000502:physiology; D012016:Reference Values; D012584:Sciatic Nerve / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D005680:gamma-Aminobutyric Acid; D001640:Bicuculline