Pressure applications of GABA localized to Purkinje cell somas in a rabbit cerebellar slice produced uniphasic hyperpolarizing responses, whereas applications of GABA that were directed at the Purkinje cell dendrites produced complex, triphasic responses with hyperpolarizing and depolarizing components. Both somatic and dendritic application of GABA elicited fast hyperpolarization (GABAhf), but dendritic application also elicited a slower depolarization (GABAd) and a later, long-lasting hyperpolarization (GABAhf). All three types of responses were accompanied by increased conductance. Use of either GABA antagonist, bicuculline or picrotoxin, eliminated the GABAhf and GABAd responses but left the GABAhl response intact. Pressure delivery of the GABA agonist, baclofen, to the dendrites but not the soma elicited a GABAhl response. Application of baclofen paired with membrane depolarization sufficient to elicit local, calcium-dependent dendritic spiking produced a persistent reduction in the GABAhl response, whereas alternating presentations of baclofen and membrane depolarization or presentations of baclofen alone could not. The fact that GABA and baclofen inhibited Purkinje cell activity in the rabbit cerebellar slice and that picrotoxin and bicuculline eliminated some, but not all of the components of the GABA response suggests the presence of both GABAA and GABAB receptors. The ability of baclofen to inhibit Purkinje cells if it was applied to the applied to the soma suggests that GABAB receptors are located predominantly on Purkinje cell dendrites. The pairing-specific change in the baclofen response suggests the existence of GABAB-mediated modifiability of Purkinje cell dendrites. Taken together, the present data provide the first electrophysiological evidence that (1) GABAA receptors are located predominantly at the Purkinje cell soma, (2) GABAB receptors are located predominantly on Purkinje cell dendrites, and (3) these GABAB receptors may be susceptible to modification.

EXPLOR_STEP=$WICRI_ROOT/Wicri/Terre/explor/CobaltMaghrebV1/Data/Istex/Checkpoint

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{{Explor lien
   |wiki=    Wicri/Terre
   |area=    CobaltMaghrebV1
   |flux=    Istex
   |étape=   Checkpoint
   |type=    RBID
   |clé=     ISTEX:FF1C2D1074766F82E5B3968BBC410740E44007E7
   |texte=   GABA-induced responses in Purkinje cell dendrites of the rabbit cerebellar slice
}}