MK-801 INHIBITS THE CORTICAL INCREASE IN IGF-1, IGFBP-2 AND IGFBP-4 EXPRESSION FOLLOWING TRAUMA

CEREBRAL contusions increase cortical expression of insulin-like growt h factor 1 (IGF-1), IGF binding protein-2 (IGFBP-2) and IGFBP-4. mRNA levels increase at the contusion site (IGF-1, IGFBP-2 and -4) and alon g the ipsilateral cortex (IGFBP-2 and -4). Here we explore whether thi s upregulation is glutamate dependent. Rats were treated with the non- competitive N-methyl-D-aspartate (NMDA) antagonist MK-801 or the non-N MDA antagonist CNQX before and after trauma, and analysed using quanti tative in situ hybridization. The induction of IGF-1 expression was co mpletely blocked by MK-801 or CNQX. IGFBP-2 mRNA levels remained high at the contusion site in the presence of either drug, but the increase was blocked in the cortex temporal to the impact by MK-801. The incre ase in IGFBP-4 mRNA was blocked by MK-801 but not by CNQX.