Effects of collagenase, elastase, and hyaluronidase on mechanical properties of isolated dog jugular veins.

To study the contribution of tissue components to the mechanical properties of veins, pressure-volume relationships were obtained with the cylindrical segments of isolated dog external jugular veins at several levels of longitudinal extension. At each length, the transmural pressure of the segment was raised up to 20 cmH2O and then reduced to 0 cmH2O by increasing and decreasing the intraluminal volume at a constant rate. The longitudinal extension of the venous segments caused a significant reduction in the incremental volume elasticity within the pressure range of 0-2 cmH2O (E0-2) as well as a significant increase of the incremental volume elasticity within 10-20 cmH2O (E10-20). The pressure-volume relationships of venous segments were also constructed in the same way after treatment with 1 mg/ml collagenase for 30 min, 0.1 mg/ml elastase for 5 min, or 1 mg/ml hyaluronidase for 60 min. Treatment with collagenase or elastase produced a significant increase of the E0-2. The treatment, however, caused no effect on E10-20. Treatment with hyaluronidase induced no effect on these mechanical parameters but produced a significant attenuation of the extension-induced decrease in E0-2. Activation of the venous smooth muscles induced by norepinephrine (10(-4) M) or high-potassium Krebs solution caused a significant decrease of E0-2 as well as a significant increase of E10-20. A complete relaxation of the smooth muscles elicited by Ca(2+)-free Krebs solution containing ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (2 mM) caused an increase of E0-2. Mechanical rubbing of the endothelium caused no significant effect on E0-2 and E10-20.(ABSTRACT TRUNCATED AT 250 WORDS)