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Updated: May 1, 2026
The Sciatic Nerve Cuffing Model of Neuropathic Pain in Mice
Published on: July 16, 2014
A peripherally acting, selective T-type calcium channel blocker, ABT-639, effectively reduces nociceptive and
Michael F Jarvis1, Victoria E Scott1, Steve McGaraughty1
1Neuroscience Research, AbbVie, R4M4, AP4A-3, 1 North Waukegan Rd., North Chicago, IL 60064, USA.
Abstract:
Activation of T-type Ca²⁺ channels contributes to nociceptive signaling by facilitating action potential bursting and modulation of membrane potentials during periods of neuronal hyperexcitability. The role of T-type Ca²⁺ channels in chronic pain is supported by gene knockdown studies showing that decreased Ca(v)3.2 channel expression results in the loss of low voltage-activated (LVA) currents in dorsal root ganglion (DRG) neurons and attenuation of neuropathic pain in the chronic constriction injury (CCI) model. ABT-639 is a novel, peripherally acting, selective T-type Ca²⁺ channel blocker. ABT-639 blocks recombinant human T-type (Ca(v)3.2) Ca²⁺ channels in a voltage-dependent fashion (IC₅₀ = 2 μM) and attenuates LVA currents in rat DRG neurons (IC₅₀ = 8 μM). ABT-639 was significantly less active at other Ca²⁺ channels (e.g. Ca(v)1.2 and Ca(v)2.2) (IC₅₀ > 30 μM). ABT-639 has high oral bioavailability (%F = 73), low protein binding (88.9%) and a low brain:plasma ratio (0.05:1) in rodents. Following oral administration ABT-639 produced dose-dependent antinociception in a rat model of knee joint pain (ED₅₀ = 2 mg/kg, p.o.). ABT-639 (10-100 mg/kg, p.o.) also increased tactile allodynia thresholds in multiple models of neuropathic pain (e.g. spinal nerve ligation, CCI, and vincristine-induced). [corrected]. ABT-639 did not attenuate hyperalgesia in inflammatory pain models induced by complete Freund's adjuvant or carrageenan. At higher doses (e.g. 100-300 mg/kg) ABT-639 did not significantly alter hemodynamic or psychomotor function. The antinociceptive profile of ABT-639 provides novel insights into the role of peripheral T-type (Ca(v)3.2) channels in chronic pain states.
Insights
ABT-639, a novel T-type calcium channel blocker, effectively reduces neuropathic pain by targeting peripheral Ca(v)3.2 channels. This selective compound shows significant antinociceptive effects without impacting normal motor or hemodynamic functions.
Area of Science:
- Neuroscience
- Pharmacology
- Pain Research
Background:
- T-type calcium channels (Ca²⁺) are implicated in nociceptive signaling and neuronal hyperexcitability.
- Ca(v)3.2 channel expression is linked to neuropathic pain, as shown by gene knockdown studies in dorsal root ganglion (DRG) neurons.
- Selective blockade of these channels offers a potential therapeutic strategy for chronic pain.
Purpose of the Study:
- To evaluate ABT-639, a novel, peripherally acting T-type calcium channel blocker, for its efficacy in preclinical pain models.
- To investigate the role of peripheral T-type (Ca(v)3.2) channels in various chronic pain conditions.
Main Methods:
- ABT-639's inhibitory activity against recombinant human T-type (Ca(v)3.2) channels and LVA currents in rat DRG neurons was assessed.
- Selectivity was determined against other calcium channel subtypes (Ca(v)1.2, Ca(v)2.2).
- Pharmacokinetic properties (oral bioavailability, protein binding, brain penetration) and antinociceptive effects in rat pain models (knee joint pain, neuropathic pain, inflammatory pain) were evaluated.
Main Results:
- ABT-639 selectively blocked Ca(v)3.2 channels (IC₅₀ = 2 μM) and LVA currents in DRG neurons (IC₅₀ = 8 μM) with high selectivity over other Ca²⁺ channels.
- The compound demonstrated favorable oral bioavailability (73%) and low brain penetration in rodents.
- ABT-639 produced dose-dependent antinociception in knee joint pain and attenuated tactile allodynia in neuropathic pain models but not inflammatory pain.
Conclusions:
- ABT-639 is a potent and selective peripheral T-type calcium channel blocker with promising antinociceptive properties.
- Its efficacy in neuropathic pain models, coupled with good oral bioavailability and limited central nervous system effects, supports its potential as a novel therapeutic agent.
- The findings highlight the critical role of peripheral Ca(v)3.2 channels in mediating chronic pain states.
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