Effect of baclofen on neuronal activity in the medial vestibular nucleus after unilateral surgical labyrinthectomy in rats.
CONCLUSIONS
Ipsilateral and contralateral medial vestibular nuclei (MVN) neurons respond differently to systemic injection of baclofen (4-amino-3-(4-chlorophenyl)-butanoic acid), illustrating the plastic changes of the type B gamma-aminobutyric acid (GABA(B)) receptor during vestibular compensation.


OBJECTIVE
To investigate the responsiveness of MVN neurons to baclofen during the early, partially compensated period after unilateral surgical labyrinthectomy.


METHODS
MVN were localized using field potentials evoked by electrical stimulation, along with a stereotaxic atlas of rat brain. Neuronal activity in MVN was recorded and analyzed in rats that had undergone labyrinthectomy with and without administration of baclofen.


RESULTS
After left labyrinthectomy the mean discharge rate in ipsilesional MVN decreased, but it was nearly restored by postoperative day 8. Baclofen (3 mg/kg) reversed the mean discharge rates between bilateral MVN at days 4 and 8 after surgical labyrinthectomy. In addition, the reduction ratio of the right MVN neurons was higher than that of the left MVN neurons.
Yu
Dongzhen
D
Department of Otolaryngology, Affiliated Sixth People's Hospital and Institute of Otolaryngology, Shanghai Jiao Tong University, Shanghai, China.
Yin
Shankai
S
Chen
Zhengnong
Z
D000818:Animals; D001418:Baclofen / Q000494:pharmacology*; D004292:Dominance, Cerebral / Q000187:drug effects; D005071:Evoked Potentials / Q000187:drug effects; D018755:GABA Agonists / Q000494:pharmacology*; D058786:GABA-B Receptor Agonists; D007273:Injections, Intramuscular; D009473:Neuronal Plasticity / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014726:Vestibular Nuclei / Q000187:drug effects*; D014722:Vestibule, Labyrinth / Q000601:surgery*
D018755:GABA Agonists; D058786:GABA-B Receptor Agonists; D001418:Baclofen