Blockade of the 3,4-methylenedioxymethamphetamine-induced changes in neurotensin and dynorphin A systems.

The levels of neurotensin-like immunoreactivity (NTLI) and dynorphin-like immunoreactivity (DLI) in the neostriatum, nucleus accumbens and substantia nigra were increased 18 h after a single administration of MDMA (3,4-methylenedioxymethamphetamine, 10 mg/kg). Coadministration of SCH 23390, a dopamine D1 receptor antagonist, or MK-801, a non-competitive antagonist of the NMDA (N-methyl-D-aspartate) receptor complex, prevented the MDMA-induced increase of NTLI and DLI in all three brain structures while the administration of sulpiride, a dopamine D2 receptor antagonist, failed to alter the MDMA effects. These findings suggest that MDMA-induced changes in neurotensin and dynorphin involve both the dopaminergic and the glutamatergic systems.