Figure 4.

Contractile responses in rings of rabbit basilar artery, without the endothelium and permeabilized by α-toxin. (a) The pCa²⁺-tension curves of the contraction induced by stepwise increment of Ca²⁺ concentrations in α-toxin-permeabilized rabbit basilar artery of control and subarachnoid haemorrhage (SAH) animals. The extent of tension development was expressed as absolute value. The data are the mean±s.e.m. (n=4–5). (b–e) Representative recordings and summary of tension development induced by 1 U ml⁻¹ thrombin (b), 10 μM PAR₁-AP (c), 10 μM GTPγS (d) and 100 nM endothelin-1 (e) during contraction induced by 300 nM Ca²⁺ in control and SAH. The contractile response was evaluated at maximal tension development or at 30 min after induction of precontraction by 300 nM Ca²⁺. The data are the mean±s.e.m. (n=4–5). ^*P<0.05 compared to that seen with no addition of thrombin or PAR₁-AP; ^#P<0.05.