Acute modulation of calcium currents and synaptic transmission by gabapentinoids

Gabapentin and pregabalin are anticonvulsant drugs that are extensively used for the treatment of several neurological and psychiatric disorders. Gabapentinoids (GBPs) are known to have a high affinity binding to alpha(2)delta-1 and alpha(2)delta-2 auxiliary subunit of specific voltage-gated calcium channels. Despite the confusing effects reported on Ca(2+) currents, most of the studies showed that GBPs reduced release of various neurotransmitters from synapses in several neuronal tissues. We showed that acute in vitro application of pregabalin could reduce in a dose dependent manner synaptic transmission in both neuromuscular junctions and calyx of Held-MNTB excitatory synapses. Furthermore presynaptic Ca2+ currents treated with pregabalin are reduced in amplitude, do not show inactivation at a clinically relevant low concentration of 100 mu M and activate and deactive faster. These results suggest novel modulatory role of acute pregabalin that might contribute to better understanding its anticonvulsant/analgesic clinical effects.