Shear stress and aortic histamine synthesis.

Aortic histamine-forming capacity (HFC) has been examined in relationship to the applied mean shear stress intensity created by pulsatile perfusion of rabbit aortas with platelet-free blood for a 1-h period. Mean shear stress intensities ranged from 22 to 109 dyn/cm2. Results indicate that a high correlation exists between the shear stress and the HFC which is described by the regression equation y = 0.28 x -6.1, where y = HFC and x = mean shear stress intensity. Results suggest that the rate of histamine formation is sensitive to the applied shear stress, and that the histidine decarboxylase system of the aorta may have the potential of serving as one coupling agent between applied hemodynamic stress and resultant alterations in aortic wall resistance to macromolecules.