Sympathetic Control of Consecutive Vascular Sections in Canine Subcutaneous Adipose Tissue

Abstract

Abstract The effects of electrical stimulation of sympathetic nerves to subcutaneous adipose tissue in the dog on the flow resistance, regional blood volume and the capillary filtration coefficient (CFC) were studied. The resting blood flow varied between 3.2–12 ml/min × 100 g and resting CFC between 0.02–0.035 ml/min × 100 g × mm Hg (mean=0.027). The regional blood content was approximately 5 ml/100 g. Stimulation of the regional sympathetic nerves induced a pronounced decrease in blood flow, a two to threefold increase in CFC, a net transcapillary fluid absorption and a decreased regional blood volume. Stimulation following administration of an α‐blocking agent produced a blood flow increase up to 25–30 ml/min × 100 g, a small CFC increase and a small venous dilation. These vascular respones were blocked by a β‐blocking agent (propranolol). In comparison with skeletal muscle the vascular bed of subcutaneous adipose tissue was found to be well dimensioned for transcapillary exchange at comparable total blood flows. This was shown by the relatively high CFC values, which indicated a large capillary surface area and/or a high capillary permeability.