AIM: To assess the blockade by CPU 86017 on the L-type calcium channels in the myocardium and on the Ca2+- related contractions of vascular smooth muscle. METHODS: The whole-cell patch-clamp was applied to investi- gate the blocking effect of CPU 86017 on the L-type calcium current in isolated guinea pig myocytes and contrac- tions by KCl or phenylephrine (Phe) of the isolated rat tail arteries were measured. RESULTS: Suppression of the L-type current of the isolated myocytes by CPU 86017 was moderate, in time- and concentration-dependent man- ner and with no influence on the activation and inactivation curves. The IC50was 11.5 μmol/L. Suppressive effect of CPU 86017 on vaso-contractions induced by KCl 100 mmol/L, phenylephrine 1 μmol/Lin KH solution (phase 1), Ca2+ free KH solution ( phase 2) , and by addition of CaCl2 into Ca2+-free KH solution (phase 3) were observed. The IC50 to suppress vaso-contractions by calcium entry via the receptor operated channel (ROC) and voltage-depen- dent channel (VDC) was 0.324 μmol/L and 16.3 μmol/L, respectively. The relative potency of CPU 86017 to suppress vascular tone by Ca2+ entry through ROC and VDC is 1/187 of prazosin and 1/37 of verapamil, respectively. CONCLUSION: The blocking effects of CPU 86017 on the L-type calcium channel of myocardium and vessel are moderate and non-selective. CPU 86017 is approximately 50 times more potent in inhibiting ROC than VDC. AIM: To assess the blockade by CPU 86017 on the L-type calcium channels in the myocardium and on the Ca2 + -related contractions of vascular smooth muscle. METHODS: The whole-cell patch-clamp was applied to investi- gate the blocking effect of CPU 86017 on the L-type calcium current in isolated guinea pig myocytes and contractions by KCl or phenylephrine (Phe) of the isolated rat tail arteries were measured. RESULTS: Suppression of the L-type current of the isolated myocytes by CPU 86017 was moderate, in time- and concentration-dependent man- ner and with no influence on the activation and inactivation curves. The IC50 was 11.5 μmol / L. Suppressive effect of CPU 86017 on vaso-contractions induced by KCl 100 mmol / L, phenylephrine 1 The IC50 to suppress vaso-contractions by calcium entry via the receptor (phase 1), Ca2 + free KH solution (phase 2), and by addition of CaCl2 into Ca2 + -free KH solution operated channel (ROC) and voltag The relative potency of CPU 86017 to suppress vascular tone by Ca2 + entry through ROC and VDC was 1/187 of prazosin and 1/37 of eC-dentin (VDC) was 0.324 μmol / L and 16.3 μmol / L, respectively. verapamil, respectively. CONCLUSION: The blocking effects of CPU 86017 on the L-type calcium channel of myocardium and vessels are moderate and non-selective. CPU 86017 is approximately 50 times more potent in inhibiting ROC than VDC.