TY - JOUR T1 - Effects of Chronic Infusion of a GABA<sub>A</sub> Receptor Agonist or Antagonist into the Vestibular Nuclear Complex on Vestibular Compensation in the Guinea Pig JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 1126 LP - 1135 DO - 10.1124/jpet.104.082172 VL - 313 IS - 3 AU - Catherine M. Gliddon AU - Cynthia L. Darlington AU - Paul F. Smith Y1 - 2005/06/01 UR - http://jpet.aspetjournals.org/content/313/3/1126.abstract N2 - The aim of this study was to determine the effects of chronic infusion of a GABAA receptor agonist/antagonist into the ipsilateral or contralateral vestibular nuclear complex (VNC) on vestibular compensation, the process of behavioral recovery that occurs after unilateral vestibular deafferentation (UVD). This was achieved by a mini-osmotic pump that infused, over 30 h, muscimol or gabazine into the ipsilateral or contralateral VNC. Spontaneous nystagmus (SN), yaw head tilt (YHT), and roll head tilt (RHT) were measured. Infusion of muscimol or gabazine into either the ipsilateral or the contralateral VNC had little effect on SN compensation. In contrast, infusion of muscimol (250, 500, and 750 ng) into the contralateral VNC and gabazine (31.25, 62.5, and 125 ng) into the ipsilateral VNC significantly affected YHT and RHT (p &lt; 0.05), but not their rate of compensation (p &gt; 0.05). Interestingly, the effects of muscimol and gabazine on YHT and RHT were consistent throughout the first 30 h post-UVD. Infusion of muscimol (62.5, 125, and 250 ng) into the ipsilateral VNC and gabazine (125, 375, and 750 ng) into the contralateral VNC had little effect on YHT and RHT or their rate of compensation. These results suggest that the ipsilateral gabazine and contralateral muscimol infusions are modifying the expression of the symptoms without altering the mechanism of compensation. Furthermore, the neurochemical mechanism responsible for vestibular compensation can cope with the both the GABAA receptor-mediated and the UVD-induced decrease in resting activity. The American Society for Pharmacology and Experimental Therapeutics ER -