GABA, THIP and baclofen inhibition of Purkinje cells and cerebellar nuclei neurons.
The sensitivity of Purkinje cells (PCs) and neurons of the cerebellar nuclei (NCNs) to iontophoretic application of gamma-aminobutyric acid (GABA), 4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol (THIP) and baclofen, i.e., GABAA and GABAB agonists respectively, have been studied in anesthetized rats. All the agonists produced dose-dependent firing rate depression of the PCs but with different potencies. The inhibitory actions of both GABA and THIP were specifically antagonized by bicuculline (Bic) and the baclofen-induced responses by 2-hydroxysaclofen. GABA and THIP also depressed the spontaneous activity of NCNs while baclofen was ineffective. The present results therefore suggest that GABAA receptors are involved in the GABA-induced inhibition in the cerebellar cortex and in the cerebellar nuclei and GABAB receptors are involved only in the cerebellar cortex.
Billard
J M
JM
Laboratoire de Physiologie de la Motricité, CNRS UR 0014, Université Pierre et Marie Curie, CHU Pitié-Salpêtrière, Paris, France.
Vigot
R
R
Batini
C
C
D000818:Animals; D001418:Baclofen / Q000494:pharmacology*; D002529:Cerebellar Nuclei / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D018756:GABA Antagonists; D007555:Isoxazoles / Q000494:pharmacology*; D009433:Neural Inhibition; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D011689:Purkinje Cells / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D018756:GABA Antagonists; D007555:Isoxazoles; D005680:gamma-Aminobutyric Acid; D001418:Baclofen; C015542:gaboxadol