Figure 4. Typical responses to transmural electrical stimulation of a coronary (upper panel) and a renal artery strip (lower panel) before and after 10 sup -5 M vecuronium. The coronary artery strip was partially contracted with prostaglandin F2alpha. The renal artery strip was transmurally stimulated under resting conditions. The artery strips were pretreated with 10 sup -6 M indomethacin plus 10 sup -5 M prazosin and with indomethacin, respectively. TTX, 3 x 10 sup -7 M tetrodotoxin; PA, 10 sup -4 M papaverine.