The effects of glutamate receptor agonists on neurotensin release using invivo microdialysis

In the present study, extracellular concentrations of neurotensin were meas ured from the striatum, nucleus accumbens and the medial prefrontal cortex in;he awake, freely moving rat. Using a highly sensitive solid phase radioi mmunoassay, basal concentrations of neurotensin were 2-5 pg/sample. In each region, glutamate receptor agonists, N-methyl-D-aspartate (NMDA) and kaini c acid, increased neurotensin release 2-3-fold. Preincubation with the Nachannel blocker tetrodotoxin abolished the glutamate receptor agonist-induc ed increases except in the striatum following kainic acid infusion. These f indings indicate that activation of glutamate receptors may indirectly stim ulate neurotensin release. (C) 2001 Elsevier Science B.V. All rights reserv ed.