Progesterone Irt Vitro Increases NMDA-evoked [3H]Dopamine Release from Striatal Slices in Proestrus Rats

R. J. CABRERA*; C. E. NAVARRO

NEUROPHARMACOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 1996 vol. 35 p. 175 - 178

0028-3908

Summary-The dopaminergic nerve terminals in rat striatum appear to be an important target for progesterone (Pg) and the excitatory amino acid glutamate. In the present study the possible interaction between glutamate and Pg upon [3H]IDA release in striatal slices from rats in proestrus was examined. [3H]DA release was augmented by NMDA in a concentration-dependent manner. The presence of Pg (400 nM) in the perfusion medium produced an amplification of the responses to NMDA (50 PM) as shown by significant increase in the tritium outflow. The NMDA selective antagonists AP-7 (100 PM) and MK-gOl(O.1 PM) prevented the effects of both NMDA and NMDA plus Pg on [3H]DA release. In contrast, the AMPA/kainate receptor antagonist CNQX (10 and 20 PM) was ineffective. Furthermore, AP-7 (100 PM) attenuated the enhancing effect of 4.00 nM Pg on [3H:jDA release evoked by 28 mM K’. The antagonist was unable to alter the effect produced byK’ alone. These results indicate a specific action of Pg on dopaminergic terminals mediated by NMDA receptors and suggest a close interaction between glutamate and dopamine systems in the striatum, apparently modulated by progesterone.