Vestibular nucleus N-methyl-D-aspartate receptors contribute to spontaneous nystagmus generation following unilateral labyrinthectomy in guinea pigs.

摘要

We investigated the effects of a non-competitive N-methyl-D-aspartate (NMDA) receptor/channel antagonist ((+)MK-801)) or an L-type Ca(2+) channel antagonist (nifedipine), delivered into the ipsilateral vestibular nucleus complex (VNC) before a unilateral labyrinthectomy (UL), on spontaneous nystagmus (SN) generation. Guinea pigs received either (+)MK-801 (5 or 12.5 microg); the less active enantiomer, (-)MK-801 (5 or 12.5 microg); nifedipine (5 or 10 microg); or vehicle, via cannula in the ipsilateral VNC. (+)MK-801, but not nifedipine, significantly decreased mean SN frequencies at 6 h post-UL, compared to controls (P<0.02) and reduced the rate of SN compensation (P<0.05). These results suggest that the SN expression is partly induced by NMDA receptor activation in the ipsilateral VNC at the time of the UL.