Effects of Adrenergic Alpha‐ and Beta‐Receptor Stimulation on the Release of Lymphocytes and Granulocytes from the Spleen

The effects of adrenergic α‐ and β‐receptor stimulating and blocking drugs on the splenic release of white cells into the blood were studied in guinea pigs. Furthermore, the effect of chemical sympathectomy was investigated. The release of white cells from the spleen was measured by the comparison between the cellular content in splenic afferent and efferent blood. The determination of the splenic blood flow with the xenon 133 clearance method enabled calculation of the number of white cells released from the spleen per min. Within 5 min after administration, noradrenaline (NA) and isoproterenol resulted in an increased splenic veno‐arterial difference in number of lymphocytes and granulocytes. As the splenic blood flow was not significantly altered, this indicates that the two drugs markedly increase the release of white cells from the spleen. NA also increased the number of lymphocytes per μl of arterial blood and the arterial haematocrit. The effects of NA were blocked by phentolamine and the effects of isoproterenol were blocked by propranolol. Propranolol, phentolamine, or chemical sympathectomy did not abolish the splenic veno‐arterial difference in cellular content found in control animals. The results indicate that the basic release of splenic lymphocytes occurring in normal guinea pigs is independent of adrenergic innervation and stimulation, and that specific adrenergic stimulation of α‐ or β‐receptors causes a considerable mobilization of lymphocytes and granulocytes from the spleen.