Pregabalin Modulation of Neurotransmitter Release Is Mediated by Change in Intrinsic Activation/Inactivation Properties of Cav2.1 Calcium Channels

In this work, we studied the effects of the anticonvulsant and analgesic drug pregabalin (PGB) on excitatory postsynaptic currents (EPSCs) at principal neurons of the mouse medial nucleus of the trapezoid body and on presynaptic calcium currents at the calyx of Held. We found that the acute application of PGB reduced the amplitude of EPSCs in a dose-dependent manner with a maximal blocking effect of approximately 30%. A clinical high-concentration dose of PGB (e. g., 500 mu M) blocked Ca(v)2.1 channel-mediated currents and decreased their facilitation during a 100-Hz train, without changing their voltage-dependent activation. Furthermore, PGB also removed the inactivation of Ca(v)2.1 channels at a clinically relevant low concentration of 100 mu M. These results suggest novel modulatory mechanisms mediated by the acute administration of PGB on fast excitatory synaptic transmission and might contribute to better understanding PGB anticonvulsant/analgesic clinical effects.