Effect of Heparin on Contractile Activity of Lymph Node Capsule.

Experiments on smooth muscle strips isolated from the capsule of bovine mesenteric lymph node showed that heparin low concentrations (0.010-0.025 U/ml) stimulating spontaneous isometric phasic contractions of smooth muscles, but higher heparin concentrations reduced or even completely eliminated these contractions. The inhibitory effects of heparin were presumably realized via stimulation of NO production by endothelial cells of the subcapsular space followed by activation of ATP-sensitive potassium channels of capsular myocytes and via modulation of prostaglandin synthesis.