Fig. 6.

L- and T-type VDCC blockers inhibit high-K⁺-induced active tension in PA rings from hypoxic mice to a greater extent than in PA rings from normoxic mice. A–C: representative tracings (a) and summarized data expressed as absolute decrease (b) and percent decrease (c) to 40K-mediated active tension in the presence of various concentrations of nifedipine (0.03–3 μM; A), mibefradil (0.03–3 μM; B), and ω-agatoxin (0.1–30 nM; C) in PA rings isolated from Nor (left, and open circles, n = 4) and Hyp (right, and solid circles, n = 4) mice. *P < 0.05 and **P < 0.01 vs. Nor. The inhibitory effects of nifedipine, a L-type VDCC blocker, and mibefradil, a T-type VDCC blocker, on 40K-induced vasoconstriction is greater in PA rings from hypoxic mice than in PA rings from normoxic mice.