Effect of chronic sympathetic denervation upon the transcapillary filtration rate induced by venous stasis.
The effect of venous pressure elevation upon capillary filtration rate in the limb was studied in 6 chronically sympathectomized patients. Five healthy subjects served as controls. Volume changes of the forearm or calf were recorded by a strain-gauge plethysmograph. Relative blood flow in subcutaneous and muscle tissue during venous stasis was measured by the local 133Xe washout technique. In the denervated limbs there was a linear relationship between net capillary filtration rate and venous pressure elevation. In the controls a non-linear relationship was seen as venous pressure elevation of 40 mmHg only caused an increase in net filtration rate of about 66% of that expected from a linear relationship. In the denervated limbs of blood flow in muscle and subcutaneous tissue remained constant during venous pressure elevation of more than 30 mmHg whereas in the non-denervated limbs blood flow decreased by about 50% in both tissues. The results suggest that a local sympathetic veno-arteriolar (axon) reflex plays a dominant role for the reduced increase in net capillary filtration during large increases in venous pressure. The local axon reflex may therefore act as an edema protecting factor.
D000328:Adult; D001369:Axons / Q000502:physiology; D002199:Capillary Permeability; D005542:Forearm / Q000098:blood supply; D006801:Humans; D007866:Leg / Q000098:blood supply; D008875:Middle Aged; D009132:Muscles / Q000098:blood supply; D012018:Reflex; D013562:Sympathectomy; D014655:Vascular Resistance; D014680:Veins / Q000294:innervation; D014690:Venous Pressure