The influence of short-duration stretch on vasoconstrictor response in rabbit aortas.

Circumferential strips of rabbit aorta were subjected to 60-second graded stretches in vitro. Before and after each stretch, the vasoconstrictor dose-responses to potassium and norepinephrine were measured. For stretch between 130 to 190% of resting length, vasoconstrictor response was progressively enhanced. However, arteries stretched 190 to 220% of resting length showed a significant fall in developed tension in response to either vasoconstrictor. Since arteries in vivo operate at 150 to 180% of resting length due to physiologic distention, it is likely that effective angioplasty does induce paralysis of vascular smooth muscle.