LEUKOCYTE MOBILIZATION FROM THE GUINEA-PIG SPLEEN BY MUSCARINIC CHOLINERGIC STIMULATION

Important interactions between the immune system and the nervous and e ndocrine systems have become increasingly accepted. The present result s demonstrate that the cholinergic agonist carbacholine greatly increa sed the number of granulocytes and lymphocytes in the splenic venous b lood, but not arterial blood, shortly after administration to guinea p igs. The effect was largely blocked by pretreatment with atropine. In contrast, animals treated with indomethacin had a decreased number of leukocytes in both splenic venous and arterial blood. A decrease in re lative splenic weight due to carbacholine treatment was also blocked b y atropine. However, cholinergic leukocyte mobilization, or that previ ously observed after adrenergic stimulation, may not be caused by caps ule contraction since it is not accompanied by mobilization of erythro cytes. Furthermore, indomethacin, which potentiates the response of sp lenic smooth muscle to adrenergic stimuli, blocked the effect of norad renaline (NA) on leukocyte mobilization.