Plasticity of gamma-aminobutyrate receptors in the medial vestibular nucleus of rat after inferior cerebellar peduncle transection.
Extracellular single unit recordings were made from regularly discharging medial vestibular nucleus neurons in brain slices from control rats and from rats surviving 7 days after bilateral transection of the inferior cerebellar peduncle. Decreases in firing rate during perfusion with the gamma-aminobutyric acid (GABA) agonists, muscimol (GABA(A)) and baclofen (GABA(B)), were greater in lesioned rats than in control rats. For the grouped data, the half-maximally-effective concentrations of muscimol and baclofen were 3.2 microM, as compared with 19.6 microM for control, and 0.8 microM, as compared with 2.7 microM for control, respectively. The antagonists bicuculline (GABA(A)) and 2-OH-saclofen (GABA(B)) only minimally affected the spontaneous firing rates of neurons in lesioned rats, significantly less than in control rats. The data suggest that the decreases of endogenous GABA levels in the medial vestibular nucleus after inferior cerebellar peduncle transection are accompanied by up-regulation of GABA(A) and, to a lesser extent, GABA(B) receptors.
Sun
Yizhe
Y
Department of Otolaryngology-Head and Neck Surgery, Medical College of Ohio, Toledo, Ohio 43614, USA.
Godfrey
Donald A
DA
Rubin
Allan M
AM
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D004594:Electrophysiology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008636:Mesencephalon / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018079:Receptors, GABA / Q000187:drug effects / Q000502:physiology*; D014726:Vestibular Nuclei / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018755:GABA Agonists; D018756:GABA Antagonists; D018079:Receptors, GABA; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D001418:Baclofen