A, left, a representative trace of effect of cumulative application of ET-1 (1 μm) and PE (30 μm) on submaximal contraction at pCa 6.7 in α-toxin-permeabilized rabbit arteries (n = 3). Right, GTPγS (30 μm)-induced contraction at pCa 6.7 (n = 5). B, left, PE did not increase a submaximal contraction at pCa 6.8 in α-toxin-permeabilized chicken artery (n = 7). ET-1 produced a significant contraction at pCa 6.8 (n = 5). Middle, GTPγS-induced contraction at pCa 6.8 (n = 9). Right, effect of 3 μm GF-109203X and 10 μm Y-27632 on pCa 6.8- and 30 μm GTPγS-induced contraction in chicken artery (n = 6). C, left, PE- and ET-1-induced contraction at pCa 6.9 in α-toxin-permeabilized pigeon arteries (n = 3). Right, GTPγS-induced contraction at pCa 6.9 (n = 5).