Fig. 15

Blood flow (electromagnetic flow probe measurement) to hindfoot (A. dors. ped.) in a catecholamine-depleted (reserpinized) anesthetized dog. a Adrenergic blockade by intravenous (i.v.) phenoxybenzamine injection has no effect on resting blood flow. Warming the anterior hypothalamus with a steretoaxically implanted thermode (water temperature at thermode entrance (T _p , white bars) distinctly increased blood flow to the hindfoot, despite α-adrenergic blockade. Persistence of thermally induced vasodilation during acetylsalicylate infusion excluded synthesis of prostaglandin as a putative transmitter. β-adrenergic (propranolol) and cholinergic (atropine) blockade did not abolish thermally induced vasodilation (not shown). b During continuous iv. infusion of hexamethonium (rate ≈ 1 mg/kg/min) resting blood flow was unchanged but the vasodilator response was abolished when hypothalamic heating was started 6 min after start of ganglion blockade. Arterial pressure (Pm _ar ) does not change. From Peter and Riedel [62]