Blocking effect of puerarin on calcium channel in isolated guinea pig ventricular myocytes

OBJECTIVE: To identify whether Puerarin (Puer) has blocking effects on L-type calcium channel. METHODS: We used whole-cell recording of patch-clamp techniques to analyse calcium channel current in ventricular myocytes isolated from Langendorff guinea pig hearts by collagenase. RESULTS: In control group, peak calcium channel current was decreased by 10.6% and 29.8% at 5, 10 min of recording time, respectively. For the same period, 0.1 mmol/L Puer reduced calcium current by 23.9% and 72.4%. 0.1 and 1 mmol/L Puer inhibited the amplitude of peak Calcium channel current by 40.6% and 63.2% after perfusing for 10 min. Compared with control group in which "rundown" phenomenon was observed, Puer also demonstrated its blocking effect on L-type channel. While washout of Puer with perfusing solution, calcium channel current went down further instead of recovery. Current-voltage (I-V) curves showed that the levels of calcium channel current were obviously decreased by Puer (both 0.1 mmo/L and 1 mmo/L) form -40 mV to +10 mV. CONCLUSION: Puer has blocking effect on L-type calcium channel in a concentration dependent manner.