Fig. 2.

Functional coupling between coronary K_V and Ca_V1.2 channels. a Protocol tracing of isolated subepicardial coronary microvessels during 4AP and nifedipine treatments (scale bar 2 min). b Elevations in microvascular tone by 4AP were abolished by inhibition of Ca_V1.2 channels with nifedipine. c Representative tracing from reactive hyperemia experiments in open-chest anesthetized swine showing effects of additive Ca_V1.2 and K_V channel blockade with diltiazem and 4AP on ischemic vasodilation (scale bar 20 s). d Addition of diltiazem to 4AP abolished the decrease in the hyperemia peak and repayment to debt responses relative to treatment with 4AP alone (data from [9]). Diltiazem administration did not significantly influence the reactive hyperemic response relative to untreated controls. *P < 0.05 vs. control, ^†P < 0.05 vs. 4AP and control