Enhanced contractile response to PAR1 agonists in the basilar artery, without endothelium after subarachnoid haemorrhage (SAH). (a, b) The level of tension induced by high K+ depolarization and endothelin-1 in the basilar artery of control and SAH, with the endothelium removed. The data are the mean±s.e.m. (n=15 in (a); n=3 for control and n=4 for SAH in (b)). *P<0.05, n.s., not significantly different. (c, d) Representative recordings of contractions induced by 1 U ml−1 thrombin (c) and 10 μM PAR1-AP (d) in the basilar artery of rabbits injected with saline (control) or autologous blood (SAH). (e) The concentration–response curves for the thrombin-induced tension development in control and SAH. The data are the mean±s.e.m. (n=4–5). * and #P<0.05 vs the resting level and the control, respectively.