Stimulant effect of human gamma globulin on smooth muscle preparations.

The effects of human gamma globulin on the contractile activity of spontaneously active rat mesenteric portal vein and guinea-pig taenia caeci and quiescent rat aorta and guinea-pig trachea muscles were studied in vitro. Human gamma globulin significantly increased the contractile activity of the spontaneously active muscles with respect to both amplitude and frequency of contraction whereas it had no significant effect on the contractile activity of quiescent muscle preparations. These findings suggest that immunoglobulins directly modulate smooth muscle including vasculature by modifying the membrane electrical activity associated with the generation of spontaneous activity.