Fig. 2

Typical recordings showing the effects of electrical stimulations of the mesencephalic ventral areas on arterial blood pressure (AP), original and mean femoral blood flow, and femoral vascular conductance in an anesthetized, paralyzed rat. A The four sites of the stimulating electrode are shown in the frontal plane at the Bregma −5.30 to 5.60 [15]. B Horizontal bars at the bottom indicate the 30-s period of electrical stimulation of each mesencephalic site. A decrease in AP in B-a spontaneously appeared prior to electrical stimulation of the SN and was not related to the electrical stimulation. MGN medial genic nucleus, PAG periaqueductal gray, SNR substantia nigra pars reticulata, VTA ventral tegmental area, IPR interpeduncular nucleus, cp cerebral peduncle