Figure 5.

Human U-II lacks contractile activity in mouse isolated aortae. (a) Log concentration-response curves to human U-II (n=8) and noradrenaline (n=8) in the mouse isolated proximal descending thoracic aorta. Values are mean and vertical bars represent the s.e.mean (n represents the number of vessels studied). Curves were derived by fitting experimental data to a logistic equation (Douglas et al., 1995). Responses are normalized to 60 mM KCl. (b) Representative experimental traces illustrating the contractile responses obtained in mouse isolated proximal descending thoracic, medial and distal abdominal aortic rings upon cumulative exposure to noradrenaline. Tone returned to basal following removal of the catecholamine from the organ bath by washing (W) at which time tissues were exposed to 1 μM human U-II. The vertical and horizontal scale bars represents tension (0.5 g) and time (10 min), respectively. All experiments were performed in endothelium-denuded vessels in the presence of 10 μM indomethacin.