Figure 5.
The effects of prolonged applications of ethanol (EtOH) on i.t. NMDA-induced increases in blood pressure in urethane-anesthetized rats. (a) Top panel: Representative recordings show increases in blood pressure induced by an i.t. injection of NMDA (2 nmol, indicated by an arrow) and the decreases in NMDA-induced pressor effects at 10 and 40 min (min) following an intravenous injection of a blous of 0.16 g ethanol (1 ml) followed by a continuous infusion at a constant rate of 0.16 g h−1. NMDA was applied i.t. every 30 min. Bottom panel: Bar graphs show changes in blood ethanol concentrations (right, y-axis; clear bar, n=4) and percentage changes in NMDA-induced increases in MAP (left, y-axis; black bar, n=6) following continuous infusion of ethanol. The peak magnitude of NMDA-induced increase in MAP immediately prior to application of ethanol is taken as control (i.e. 100%); the increase in MAP was 22±3.6 mmHg (n=6). *Statistically different from control; #Statistically different from the changes at 10 min after administration of ethanol. (b) Similar to the legend of (a) except that ethanol was administered with an initial dose of 0.32 g. The blood ethanol concentrations and ethanol effects on NMDA-induced increases in MAP were determined from four and five rats, respectively. NMDA-induced increase in MAP before the application of ethanol was 19±3.2 mmHg (n=5).