Blood flow redistribution in the transposition response of the rat

Changes in blood flow in different arteries occurring in the transposition response of the rat, induced by transposing the animal from a "home" cage to a new one, were studied using chronically implanted electromagnetic flow probes. In the response, hindquarter flow was increased by more than 50%, superior mesenteric and renal flows were decreased by about 30 and 15%, respectively, and common carotid flow remained almost unchanged. The increase in hindquarter flow in the response was much less after beta-adrenoceptor blockade with propranolol. In adrenalectomized rats the flow changes in the hindquarter, mesenteric, and renal areas were less marked in either direction. These findings indicate that the blood flow redistribution in the transposition response is characterized by a shift of flow from the viscera to the skeletal muscles, in which the alpha- and beta-effects of catecholamines released from the adrenal medulla in the response play a dominant role.