Contractile response of isolated human vessels with special regard to stretch and storage

The effect of stretch and storage of isolated human blood vessels was studied in vitro. The following observations were made. 1. Umbilical vessel preparations exhibited spontaneous rhythmic activity whereas other vessels showed this only after storage. Amplitude but not frequency of this activity increased after stretching. 2. Innervated vessel preparations showed increased sensitivity and maximal response to noradrenaline after storage. This can probably be explained by denervation supersensitivity and receptor upregulation and the rhythmic responses after storage may reflect unstable membrane potentials and prostaglandin synthesis.