Expression of NMDA, AMPA and GABAA receptor subunit mRNAs in the rat auditory brainstem. I. Influence of early auditory deprivation

Impact of early post-natal deafening on auditory pathways was investigated in newborn rats deafened by daily amikacin injections from P7 to P16 induci ng a complete destruction of the organ of Corti. The expression of mRNAs en coding N-methyl-D-aspartate (NMDA), alpha -amino-3-hydroxy-5-methyl-4-isoxa zole (AMPA) and gamma -aminobutyric acid type A (GABA(A)) receptor subunits was then studied by in situ hybridization in the dorsal and ventral cochle ar nucleus and in the central nucleus of the inferior colliculus (CNIC). Ea rly post-natal deafening decreased bilaterally the expression of mRNAs enco ding NR1, NR2a, NR2b and flop isoforms of AMPA receptors. On the contrary, it increased the expression of mRNAs encoding some GABA(A) subunits (alpha1 , beta1, gamma2) and flip isoforms of AMPA receptors. These changes were mo re pronounced in cochlear nuclei than in CNIC. They suggest that auditory s ensation is essential in the normal development of central auditory pathway s. (C) 2000 Elsevier Science B.V. All rights reserved.