Disappearance of ¹³³Xenon and ¹²⁵Iodide and Extraction of ⁸⁶Rubidium in Subcutaneous Adipose Tissue during Sympathetic Nerve Stimulation

Effects of sympathetic nerve stimulation on the disappearance rates of 133 Xenon and 125 Iodide from a local depot as well as on the extraction of 86 Rubidium from blood have been studied in the subcutaneous adipose tissue of dogs during constant blood flow perfusion. Resting mean k‐values for 133 Xenon were 0.0040 min ‐1 (n = 10) and for 125 Iodide 0.0386 min ‐1 (n = 5) while the PS‐products for 86 Rubidium had a mean value of 2.5 ml × min ‐1 X 100 g ‐1 (n = 17). During sympathetic nerve stimulation a frequency dependent decrease of disappearance rates and PS‐products was found. The latter were reduced by an average of 30 % while the reductions of the disappearance rates were twice as large and similar for 133 Xenon and 125 Iodide. These results suggest a decrease in the perfused capillary surface area during sympathetic nerve stimulation.