The cerebral arteries were from groups of fresh air, SHS and SHS treatment with GW5074 for 8 weeks. K+-induced responses were expressed as absolute values of contraction (mN). S6c and ET-1-induced responses were expressed as percentage of K+-induced contraction. *P < 0.05 versus fresh air group. Emax, maximal contraction; pEC50, negative logarithm of the concentration that produces 50% of the maximal contractile effect; SHS, secondhand smoke exposure; GW, GW5074 (0.5 mg/kg).