The role of ionotropic receptors of glutaminic acid in cardiovascular system. A. The influence of ionotropic receptor NMDA agonist - 1R,3R-ACPD and antagonist - DL-AP7 on the systemic pressure in rats.

The aim of our study was to estimate the involvement of the peripheral N-methyl-D-aspartate receptors in regulation of cardiovascular function. For this purpose we examined the effects of intravenous injection of the agonists - NMDA (0.025; 0.05 and 1.0 mg/kg iv) and 1R-3R-ACPD (0.025; 0.05 and 1.0 mg/kg iv) - and antagonist of NMDA receptors DL-AP7 (0.02; 0.07 and 0.2 mg/kg iv). To determine if the effects of NMDA come from central or peripheral action we observed the effect during blockade of autonomic ganglion by using the nicotinic receptor antagonist - chlorisondamine (1.25 mg/kg iv). Administration of NMDA in three doses evoked slight hypotension after injection of the medium dose, 0.05 mg/kg. In the condition of pretreatment with 1.25 mg/kg chlorisondamine the hypotensive effect of NMDA was markedly reduced, what might suggest that NMDA-induced hypotension raised from the action within the brain. The competetive NMDA receptor antagonist DL-AP7 slightly increased the blood pressure. None of the injected drug had an influence on the heart rate in our in vivo study. It is concluded that the peripherally localized NMDA receptors may take a part in regulation of cardiovascular system, since their stimulation or blockade evoked the changes of systemic pressure.