Voltage-Gated Calcium Channels Play a Central Role in Caenorhabditis elegans Response to Noxious Heat.

Voltage-gated calcium channels (VGCCs) are critical for calcium ion influx during action potentials, playing a key role in neurotransmitter release, synaptic transmission, and pain perception. We hypothesized that gabapentin (GBP) and pregabalin (PGB) interact with VGCCs, particularly the auxiliary α2δ subunit, in C. elegans. Our goal was to investigate VGCCs' role in nociception and assess C. elegans as a screening model for antinociceptive compounds. We exposed C. elegans to varying GBP and PGB concentrations, followed by thermal avoidance assays (32-35 °C) and proteomic analyses. Both drugs significantly impeded nocifensive responses at 100 µM, with diminished efficacy at higher concentrations. Mutant strains unc-2 and unc-36 exhibited impaired heat avoidance, confirming VGCCs' involvement in nociceptive signaling. Proteomic analysis revealed distinct drug-specific pathway modulations. Our study demonstrated that both pregabalin and gabapentin are associated with calcium activity either directly or indirectly. Although both drugs influence VGCC, pregabalin exhibited greater efficiency compared to gabapentin in mammals. Our data also clearly indicates that calcium-related pathways were more prominently upregulated or downregulated in the pregabalin treatment group compared to gabapentin. GBP 100 µM modulate mostly muscle or actinomycin related pathways. Conversely, at 500 µM, GBP activates pathways linked to translation and ribosomal biogenesis, potentially enhancing pro-neuropeptide synthesis, which may counteract its antinociceptive effects. PGB exhibits similar concentration-dependent effects, with the 100 µM treatment suppressing glutamatergic signaling and the 500 µM treatment failing to suppress neurotransmitter release. This might be due to the influence of SUMOylation, which enhances the release of pro-nociceptive neurotransmitters, or receptor saturation as we see ligand gated ion channels are highly expressed in this cohort. Our findings support the use of C. elegans as a model for screening novel analgesics and provide insight into the multiple molecular pathways underlying gabapentinoid-mediated pain modulation.