Figure 4.

Time-course effects on changes in mean arterial blood pressure (ΔMAP) (A) and heart rate (ΔHR) (B) induced by R-820 (500 pmol) injected into the ventral tegmental area (VTA) before and 30 min after treatment with the D₂R antagonist raclopride (0.16 mg kg⁻¹, i.v.). Areas under the curves (AUC) were measured for a period of 0–5 h (small insets). Values represent the mean ± SEM of n rats. Significant difference from aCSF values (*) or R-820 (†) is indicated by *†P < 0.05; **††P < 0.01; ***†††P < 0.001.