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