REGULATION OF THE GLIAL GLUTAMATE TRANSPORTER GLT-1 BY GLUTAMATE AND DELTA-OPIOID RECEPTOR STIMULATION

The excitatory effect of presynaptically released glutamate is tightly regulated and terminated by high affinity sodium-dependent glutamate transporters. The regulation of the glial glutamate transporter GLT-1 is potentially important in synaptic modulation. Using astroglial cult ures prepared from the rat cerebral cortex, we found that the delta-op ioid receptor agonist [D-pen(2),D-pen(5)]-enkephalin decreases and glu tamate increases the expression of the GLT-1 transporter mRNA, Corresp onding changes in the uptake kinetics were found after incubation for 48 h with the respective agonists when glial glutamate uptake was meas ured in primary astroglial cultures. The data suggest that long-term r eceptor activation induces alterations in glial glutamate uptake prope rties. (C) 1998 Federation of European Biochemical Societies.