Pregabalin Reduces the Release of Synaptic Vesicles from Cultured Hippocampal Neurons

Abstract

Pregabalin [S-[ϩ]-3-isobutylGABA or (S)-3-(aminomethyl)-5-methylhexanoic acid, Lyrica] is an anticonvulsant and analgesic medication that is both structurally and pharmacologically related to gabapentin (Neurontin; Pfizer Inc., New York, NY). Previous studies have shown that pregabalin reduces the release of neurotransmitters in several in vitro preparations, although the molecular details of these effects are less clear. The present study was performed using living cultured rat hippocampal neurons with the synaptic vesicle fluorescent dye probe FM4-64 to determine details of the action of pregabalin to reduce neurotransmitter release. Our results indicate that pregabalin treatment, at concentrations that are therapeutically relevant, slightly but significantly reduces the emptying of neurotransmitter vesicles from presynaptic sites in living neurons. Dye release is reduced in both glutamic acid decarboxylase (GAD)-immunoreactive and GAD-negative (presumed glutamatergic) synaptic terminals. Furthermore, both calcium-dependent release and hyperosmotic (calcium-independent) dye release are reduced by pregabalin. The effects of pregabalin on dye release are masked in the presence of L-isoleucine, consistent with the fact that both of these compounds have a high binding affinity to the calcium channel ␣ 2 -␦ protein. The effect of pregabalin is not apparent in the presence of an N-methyl-D-aspartate (NMDA) antagonist [D(Ϫ)-2-amino-5-phosphonopentanoic acid], suggesting that pregabalin action depends on NMDA receptor activation. Finally, the action of pregabalin on dye release is most apparent before and early during a train of electrical stimuli when vesicle release preferentially involves the readily releasable pool.

In vivo imaging reveals that pregabalin inhibits cortical spreading depression and propagation to subcortical brain structures

“…Given that pregabalin did not prevent subcortical invasion in S218L mice, we would argue that pregabalin suppresses excitability sufficiently to prevent SD propagation through failure points that block the spread of SD into subcortical structures in the milder R192Q phenotype mice. Previous studies have demonstrated that pregabalin inhibits vesicle trafficking in hippocampal neurons, reducing the readily releasable pool (44) and attenuating vesicle release (45). In hippocampal brain slices, we observed that pregabalin (500 μM) effectively suppressed both spontaneous and evoked synaptic activity in WT and R192Q CA1 neurons but not in S218L CA1 neurons.…”

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

“…There have been few reports showing acute PGB blocking effects on calcium currents at either cultured neurons Sutton et al, 2002) or heterologous systems (Hendrich et al, 2008) or PGB-mediated reduction of synaptic transmission at both cultured hippocampal neurons (Micheva et al, 2006) and neuromuscular junction (Joshi and Taylor, 2006). Eroglu et al (2009) demonstrated that the ␣ 2 -␦ subunit is involved in excitatory synapse formation and suggested a therapeutic role for gabapentin (a PGB analog) mediated by the blocking of new synapse formation.…”

“…); Agencia Nacional de Promoción Científica y Tecnológica-Fondo para la Investigación Científica y Tecnológica, Banco Interamericano de Desarrollo-Proyectos de Investigación Científica y Tecnológica [Grants PICT-2007-1009, PICT-2008PICT- -2019; and Agencia Nacional de Promoción Científica y Tecnológica-Proyectos de Investigación para la Radicación/Relocalización de Investigadores-Programa de Recursos Humanos(for review, see Taylor et al, 2007), by interacting with ␣ 2 -␦ auxiliary subunits Martin et al, 2002;Sutton et al, 2002). Concomitantly, PGB reduces evoked postsynaptic responses (Cunningham et al, 2004;Joshi and Taylor, 2006;Micheva et al, 2006). In contrast, studies with recombinant voltage-gated calcium channels have not shown any acute effect of PGB on channel function (Hendrich et al, 2008).…”

“…A broad range of concentrations of PGB have been used in previous reports (McClelland et al, 2004;Beydoun et al, 2005;Micheva et al, 2006). After a single in vivo administration of PGB, its relevant clinical concentration in plasma was found to reach up to 120 M (Johannessen et al, 2003), whereas higher concentrations such as 500 M were expected after multiple doses (plasma half-life ϳ6 h) (Beydoun et al, 2005).…”

A rat model of FOLFOX-induced neuropathy: effects of oral dimiracetam in comparison with duloxetine and pregabalin

“…Moreover, dimiracetam was effective in preclinical models of chemotherapy-induced neuropathic pain triggered by the anticancer compounds oxaliplatin or sorafenib or by antiretroviral drugs [14,40]. To note, the racetam derivative as well as pregabalin act throughout the glutamatergic system, since pregabalin reduces the release of synaptic vesicles from glutamatergic neurons [41], and dimiracetam decreases the NMDA-induced release of glutamate in synaptosomal preparations from rat spinal cord [14]. Recently, we reported that the glutamate release was enhanced in cerebrocortical nerve terminals of oxaliplatin-treated rats [42].…”