STIMULANT EFFECT OF HUMAN GAMMA-GLOBULIN ON SMOOTH-MUSCLE PREPARATIONS

The effects of human gamma globulin on the contractile activity of spo ntaneously active rat mesenteric portal vein and guinea-pig taenia cae ci and quiescent rat aorta and guinea-pig trachea muscles were studied in vitro. Human gamma globulin significantly increased the contractil e activity of the spontaneously active muscles with respect to both am plitude and frequency of contraction whereas it had no significant eff ect on the contractile activity of guiescent muscle preparations. Thes e findings suggest that immunoglobulins directly modulate smooth muscl e including vasculature by modifying the membrane electrical activity associated with the generation of spontaneous activity.