Fig. (6).

Inhibition of hva (=high-voltage-activated) Ca²⁺ currents by PGE₂ and various EP agonists. A: Leak-subtracted Ca²⁺ currents of a rat superior cervical ganglion cell in control and in 1 μM PGE₂. B: Current-voltage curves from the experiment in A in control (o) and in PGE₂ (● , current 10 ms after start of pulse; ■, rapid component of Ca²⁺ current rising phase determined by double exponential fit). A and B from [45]. C: Concentration-response curves for the inhibition of hva Ca²⁺ current of rat paratracheal ganglion cells by various prostanoid agonists. Peak Ca²⁺ currents were measured with pulses to +10 or +20 mV and expressed as fraction of control current. From [48]. D: Inhibition of hva Ca²⁺ current of Type 1 (■) and Type 2 (▲) mouse trigeminal neurons by the EP₃ agonist ONO-AE-248. From [14].