Regulation of the glial glutamate transporter GLT‐1 by glutamate and δ‐opioid receptor stimulation

Abstract

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 cultures prepared from the rat cerebral cortex, we found that the δ-opioid receptor agonist [d-pen²,d-pen⁵]-enkephalin decreases and glutamate increases the expression of the GLT-1 transporter mRNA. Corresponding changes in the uptake kinetics were found after incubation for 48 h with the respective agonists when glial glutamate uptake was measured in primary astroglial cultures. The data suggest that long-term receptor activation induces alterations in glial glutamate uptake properties.