Figure 6.

N-arachidonoyl dopamine (NADA) and N-arachidonoyl glycine (NAGly) do not strongly affect Ca_V3.1 channel kinetics. Whole-cell patch clamp recordings were made from human Ca_V3 channels stably expressed in HEK 293 cells. Channel activation from a holding potential of −106 mV was measured 5 min after breaking into the cell and then again after 5 min in NADA (500 nmol·L⁻¹), NAGly (10 µmol·L⁻¹) or anandamide (AEA, 300 nmol·L⁻¹). The graphs illustrate: (A) current amplitude at −26 mV, the time to peak and time constant of inactivation at (B) −26 mV and (C) −46 mV. The values in drug are expressed as a percentage of the values at 5 min, control cells were continuously superfused with vehicle alone. Each bar represents the mean ± SEM of at least six cells. Statistical comparisons were made with control cells recorded on the same day (Student's t-test, *P < 0.05, **P < 0.01). Panel (D) illustrates typical currents elicited by a step from −106 mV to −26 mV recorded in control conditions and after 5 min in NADA, AEA and NAGly. Currents have been normalized to the peak inward current to allow ready comparison of inactivation kinetics.