on the basis of our findings , we conclude that 1 ) spontaneous tone depends on calcium influx , presumably through specific stretch-operated membrane channels , 2 ) these stretch-dependent channels are blocked by d-600 and nifedipine , 3 ) spontaneous tone is enhanced in doca hypertension , and 4 ) the endothelium appears to act as a receptor for stretch , mediating -- at least in part -- the spontaneous contractile response by releasing a constrictor agent .
C0028066
nifedipine
C0020538
hypertension