Inhibited effects of amitriptyline on rabbit basilar and mesenteric artery rings

The effects of amitriptyline (Ami) on isolated rabbit basilar and mesenteric artery rings were studied and compared with verapamil (Ver). Ami inhibited the contraction of the rabbit basilar and mesenteric artery rings evoked by KCl, CaCl2 and norepinephrine, noncompetitively. The pD'2 values for Ami to antagonize effects of KCl, CaCl2, NE on both arteries were 5.79 +/- 0.10 and 4.97 +/- 0.12 (P less than 0.01), 4.50 +/- 0.30 and 4.58 +/- 0.12 (P greater than 0.05), 5.80 +/- 0.13 and 5.56 +/- 0.12 (P less than 0.01), respectively. The characteristics of such effects of Ami were the same as Ver. The results suggest that Ami may block calcium channels and inhibit rabbit basilar artery selectively.