EFFECTS OF DIETHYLENETRIAMINE ON NMDA-INDUCED INCREASE OF BLOOD-PRESSURE IN RATS

We investigated the effects of three doses of diethylenetriamine (DET; 0.1-10 nmol/rat), putative ligand at the polyamine site on NMDA recep tors, on blood pressure increase induced by N-methyl-D-aspartate (NMDA , 2 nmol/rat) microinjected at the periaqueductal gray (PAG) matter. S aid doses of DET did not modify basal arterial blood pressure. Pretrea tment with DET, depending on the dose used, either potentiated (DET, 0 .1 nmol/rat), reduced (DET, 1 nmol/rat) the NMDA effects or left them unchanged (DET, 10 nmol/rat). DET 10 nmol/rat, microinjected 5 min bef ore spermidine (SPD, 0.02-2 nmol/rat), significantly antagonized SPD m odulation on the NMDA-induced presser changes. These data, in agreemen t with the functional findings in vitro, suggest that also in vivo DET has pharmacological activities quite different from a pure antagonist but shows multiple actions on the NMDA receptors. (C) 1998 Elsevier S cience Inc.