Carboxylate bioisosteres of gabapentin.

A series of carboxylate bioisosteres of structures related to gabapentin 1 have been prepared. When the carboxylate was replaced by a tetrazole, this group was recognized by the alpha2-delta protein. Further characterization of alpha2-delta binding compounds 14a and 14b revealed a similar pattern of functional in vitro and in vivo activity to gabapentin 1.

Preferential action of gabapentin and pregabalin at P/Q-type voltage-sensitive calcium channels: inhibition of K+-evoked [3H]-norepinephrine release from rat neocortical slices.

Gabapentin (GBP; Neurontin) and pregabalin (PGB; CI-1008), efficacious drugs in several neurological and psychiatric disorders, inhibit neurotransmitter release from mammalian brain slices at therapeutically relevant concentrations. A detailed investigation, exploring the basis for this in vitro phenomenon, focused on norepinephrine (NE) and rat neocortical tissue in complementary assays of neurotransmitter release and radioligand binding. The results are consistent with the hypothesis that GBP, PGB, and related substances decrease neocortical NE release by acting at the alpha2delta subunit of presynaptic P/Q-type voltage-sensitive Ca2+ channels (VSCC) subserving Ca2+ influx in noradrenergic terminals.