TABLE 7

CaV2.2 channels

Channel name CaV2.2
Description Voltage-gated calcium channel α1 subunit
Other names N-type, α1B; rbB-I, rbB-II (in rat),1,2 BIII (in rabbit)3
Molecular information Human: 2339aa, M94172, 2237aa, M94173,4 chr. 9q34, CACN1B
Rat: 2336aa, M929051
Mouse: 2329aa, NM007579, NP031605
Associated subunits α2δ/β1, β3, β4,5 possibly γ
Functional assays Voltage-clamp, patch-clamp, calcium imaging, neurotransmitter release, 45Ca uptake into synaptosomes
Current ICa,N
Conductance 20pS (bullfrog sympathetic neurones)6; 14.3pS (rabbit BIII cDNA in skeletal muscle myotubes)3
Ion selectivity Ba2+ > Ca2+
Activation Va = +7.8 mV, τa = 3 ms at +10 mV (human α1B/α2δ/β1-3 in HEK293 cells, 15 mM Ba2+ charge carrier)4,7; Va = +9.7 mV, τa = 2.8 ms at +20 mV (rat α1B-II/β1b, in Xenopus oocytes, 40 mM Ba2+ charge carrier)2
Inactivation Vh = –61 mV, τh ∼200 ms at +10 mV (human α1B/α2δ/β1-3 in HEK293 cells, 15 mM Ba2+ charge carrier)4,7; Vh = –67.5 mV; τh = 112 ms at +20 mV (rat α1B-II/β1b in Xenopus oocytes, 40 mM Ba2+)2
Activators None
Gating modifiers None
Blockers ω-conotoxin GVIA (1–2 μM, irreversible block), ω-conotoxin MVIIA (SNX-111, Ziconotide/Prialt), ω-conotoxin MVIIC8; other blockers include piperidines, substituted diphenylbutylpiperidines, long alkyl chain molecules, aliphatic monoamines, tetrandine, gabapentin, peptidylamines, volatile anesthetics, the peptide toxins SNX-325 and DW13.3, as well as the ω-conotoxins SVIA, SVIB, and CVID20,21,22,23,24,25,26,27,28,29,30a,30b,30c,30d,30e,31,32,33,34
Radioligands [125I]ω-conotoxin GVIA (Kd = 55 pM, human α1B/α2δ/β1-3 in HEK293 cells)4
Channel distribution Neurons (presynaptic terminals, dendrites, cell bodies)9
Physiological functions Neurotransmitter release in central and sympathetic neurons10; sympathetic regulation of the circulatory system11,35; activity and vigilance state control36; sensation and transmission of pain (see “Pharmacological significance” and “Comments”)
Mutations and pathophysiology Differing reports exist: mice lacking a functional CaV2.2 gene exhibit a normal life span and no detectable behavioral modifications compared with wild type but possess an increase in basal mean atrial pressure and other functional alterations to the sympathetic nervous system11–however, in a different study, approximately 1/3 of the mice lacking a functional CaV2.2 gene did not survive to weaning, but surviving animals were normal except for a decrease in anxiety-related behavior and a suppression of inflammatory and neuropathic pain responses12; no point mutations in the native CaV2.2. gene have been reported to date
Pharmacological significance In rats, intrathecal administration of ω-conotoxin GVIA or ω-conotoxin MVIIA shows strong effects on inflammatory pain, postsurgical pain, thermal hyperalgesia, and mechanical allodynia13,14,15; in humans, intrathecal administration of SNX-111 (Ziconotide/Prialt, synthetic ω-conotoxin MVIIA) to patients unresponsive to intrathecal opiates significantly reduced pain scores and in a number of specific instances resulted in relief after many years of continuous pain16
Comments In case studies, Ziconotide/Prialt has been examined for usefulness in the management of intractable spasticity following spinal cord injury in patients unresponsive to baclofen and morphine17; side effects of intrathecal administration of Ziconotide/Prialt include nystagmus, sedation, confusion, auditory and visual hallucinations, severe agitation, and unruly behavior18; intravenous administration of Ziconotide to humans results in significant orthostatic hypotension19; identified regions of alternative splicing include the domain I-II linker, domain II-III linker, IIIS3-IIIS4, IVS3-IVS4, and the carboxyl terminus1,2,3,4,37,38,39; splicing affects a number of channel properties, including current-voltage relations and kinetics, and is associated with cell-specific expression–in particular, expression of the e37a splice isoform in dorsal root ganglia correlates with a subset of nociceptive neurons40,41,42; alternative splicing also alters interactions with intracellular synaptic proteins such as Mint1, CASK, syntaxin, and SNAP-2543,44,45

  • aa, amino acid; chr., chromosome; HEK, human embryonic kidney.

  • ↵1. Dubel SJ, Starr TV, Hell J, Ahlijanian MK, Enyeart JJ, Catterall WA, and Snutch TP (1992) Molecular cloning of the α1 subunit of an ω-conotoxin-sensitive calcium channel. Proc Natl Acad Sci USA 89:5058-5062

  • ↵2. Stea A, Dubel SJ, and Snutch TP (1999) α1B N-type calcium channel isoforms with distinct biophysical properties. Ann NY Acad Sci 868:118-130

  • ↵3. Fujita Y, Mynlieff M, Dirksen RT, Kim M, Niidome T, Nakai J, Friedrich T, Iwabe N, Miyata T, Furuichi T, et al. (1993) Primary structure and functional expression of the ω-conotoxin-sensitive N-type calcium channel from rabbit brain. Neuron 10:585-598

  • ↵4. Williams ME, Brust PF, Feldman DH, Patthi S, Simerson S, Maroufi A, McCue AF, Velicelebi G, Ellis SB, and Harpold M (1992) Structure and functional expression of an ω-conotoxin-sensitive human N-type calcium channel. Science 257:389-395

  • ↵5. Scott VE, De Waard M, Liu H, Gurnett CA, Venzke DP, Lennon VA, and Campbell KP (1996) β subunit heterogeneity in N-type calcium channels. J Biol Chem 271:3207-3212

  • ↵6. Elmslie KS (1997) Identification of the single channels that underlie the N-type and L-type calcium currents in bullfrog sympathetic neurons. J Neurosci 17:2658-2668

  • ↵7. Williams ME, Marubio LM, Deal CR, Hans M, Brust PF, Philipson L. Miller RJ, Johnson EC, Harpold MM, and Ellis SB (1994) Structure and functional characterization of neuronal α1E calcium channel subtypes. J Biol Chem 269:22347-22357

  • ↵8. Hillyard DR, Monje VD, Mintz IM, Bean BP, Nadasdi L, Ramachandran J, Miljanich G, Azimi-Zoonooz A, McIntosh JM, Cruz LJ, et al. (1992) A new conus peptide ligand for mammalian presynaptic calcium channels. Neuron 9:9-77

  • ↵9. Westenbroek RE, Hell JW, Warner C, Dubel SJ, Snutch TP, and Catterall W (1992) Biochemical properties and subcellular distribution of an N-type calcium channel α1 subunit. Neuron 6:1099-1115

  • ↵10. Dunlap K, Luebke JI, and Turner TJ (1995) Exocytotic calcium channels in mammalian central neurons. Trends Neurosci 18:9-98

  • ↵11. Ino M, Yoshinaga T, Wakamori M, Miyamoto N, Takahashi E, Sonoda J, Kagaya T, Oki T, Nagasu T, Nishizawa Y, et al. (2001) Functional disorders of the sympathetic nervous system in mice lacking the α1B subunit (CaV2.2) of N-type calcium channels. Proc Natl Acad Sci USA 98:323-5328

  • ↵12. Saegusa H, Kurihara T, Zong S, Kazuno A, Matsuda Y, Nonaka T, Han W, Toriyama H, and Tanabe T (2001) Suppression of inflammatory and neuropathic pain symptoms in mice lacking the N-type calcium channel. EMBO J 20:2349-2356

  • ↵13. Malmberg AB and Yaksh TL (1994) Voltage-sensitive calcium channels in spinal nociceptive processing: blockade of N- and P-type channels inhibits formalin-induced nociception. J Neurosci 14:4882-4890

  • ↵14. Bowersox SS, Gadbois T, Singh T, Pettus M, Wang Y-X, and Luther RR (1996) Selective N-type neuronal voltage-sensitive calcium channel blocker, SNX-111, produces spinal antinociception in rat models of acute, persistent and neuropathic pain. J Pharmacol Exp Ther 279:1243-1249

  • ↵15. Sluka KA (1998) Blockade of N- and P/Q-type calcium channels reduces the secondary heat hyperalgesia induced by acute inflammation. J Pharmacol Exp Ther 287:232-237

  • ↵16. Vanegas H and Schaible HG (2000) Effects of antagonists to high-threshold calcium channels upon spinal mechanisms of pain, hyperalgesia and allodynia. Pain 85:9-18

  • ↵17. Ridgeway B, Wallace M, and Gerayli A (2000) Ziconotide for the treatment of severe spasticity after spinal cord injury. Pain 85:287-289

  • ↵18. Penn RD and Paice JA (2000) Adverse effects associated with the intrathecal administration of Ziconotide. Pain 85:291-296

  • ↵19. McGuire D, Bowersox S, Fellmann JD, and Luther RR (1997) Sympatholysis after neuron-specific, N-type, voltage-sensitive calcium channel blockade: first demonstration of N-channel function in humans. J Cardio Pharm 30:400-403

  • ↵20. Ramilo CA, Zafaralla GC, Nadasdi L, Hammerland LG, Yoshikami D, Gray WR, Kristipati R, Ramachandran J, Miljanich G, and Olivera BM (1992) Novel α- and ω-conotoxins from Conus striatus venom. Biochemistry 31:9919-9926

  • ↵21. Grantham CJ, Main MJ, and Cannell MB (1994) Fluspirilene block of N-type calcium current in NGF-differentiated PC12cells. Br J Pharmacol 111:483-488

  • ↵22. Sah DW and Bean BP (1994) Inhibition of P-type and N-type calcium channels by dopamine receptor antagonists. Mol Pharmacol 45:84-92

  • ↵23. Weinsberg F, Bickmeyer U, and Wiegand H (1994) Effects of tetrandrine on calcium channel currents of bovine chromaffin cells. Neuropharmacology 33:885-890

  • ↵24. Sutton KG, Siok C, Stea A, Zamponi GW, Heck SD, Volkmann RA, Ahlijanian MK, and Snutch TP (1998) Inhibition of neuronal calcium channels by a novel peptide spider toxin, DW13.3. Mol Pharmacol 54:407-418

  • ↵25. Roullet JB, Spaetgens RL, Burlingame T, Feng ZP, and Zamponi GW (1999) Modulation of neuronal voltage-gated calcium channels by farnesol. J Biol Chem 274:25439-25446

  • ↵26. Hu LY, Ryder TR, Rafferty MF, Siebers KM, Malone T, Chatterjee A, Feng MR, Lotarski SM, Rock DM, Stoehr SJ, et al. (2000) Neuronal N-type calcium channel blockers: a series of 4-piperidinylanilineanalogs with analgesic activity. Drug Des Discov 17:85-93

  • ↵27. Hu LY, Ryder TR, Rafferty MF, Taylor CP, Feng MR, Kuo BS, Lotarski SM, Miljanich GP, Millerman E, Siebers KM, et al. (2000) The discovery of [1-(4-dimethylaminobenzyl)-piperidin-4-yl]-[4-(3,3-dimethylbutyl)-phenyl]-(3-methyl-but-2-enyl)-amine, an N-type Ca2+ channel blocker with oral activity for analgesia. Bioorg Med Chem 8:1203-1212

  • ↵28. Ryder TR, Hu LY, Rafferty MF, Millerman E, Szoke BG, and Tarczy-Hornoch K (1999) Multiple parallel synthesis of N,N-dialkyldipeptidylamines as N-type calcium channel blockers. Bioorg Med Chem Lett 9:1813-1818

  • ↵29. Kamatchi GL, Chan CK, Snutch T, Durieux ME, and Lynch III C (1999) Volatile anesthetic inhibition of neuronal Ca channel currents expressed in Xenopus oocytes. Brain Res 831:85-96

  • ↵30a. Snutch TP and Zamponi GW (2000) inventors, NeuroMed Technologies, Inc., assignee. Calcium channel blockers. U.S. patent 6,011,035. 2000 Jan 4

  • ↵30b. Snutch TP and Zamponi GW (2001) inventors, NeuroMed Technologies, Inc., assignee. Calcium channel blockers. U.S. patent 6,294,533. 2001 Sep 25

  • ↵30c. Snutch TP (2001) inventor, NeuroMed Technologies, Inc., assignee. Fused ring calcium channel blockers. U.S. patent 6,310,059. 2001 Oct 30

  • ↵30d. Snutch TP (2002) inventor, NeuroMed Technologies, Inc., assignee. Preferentially substituted calcium channel blockers. U.S. patent 6,387,897. 2002 May 14

  • ↵30e. Snutch TP (2002) inventor, NeuroMed Technologies, Inc., assignee. Partially saturated calcium channel blockers. U.S. patent 6,492,375. 2002 Dec 10

  • ↵31. Beedle AM and Zamponi GW (2000) Block of voltage-dependent calcium channels by aliphatic monoamines. Biophys J 79:260-270

  • ↵32. Lewis RJ, Nielson KJ, Craik DJ, Loughnan ML, Adams DA, Sharpe IA, Luchian T, Adams DJ, Bond T, Thomas L, et al. (2000) Novel ω-conotoxins from Conus catus discriminate among neuronal calcium channel subtypes. J Biol Chem 275:35335-35344

  • ↵33. Martin DJ, McClelland D, Herd MB, Sutton KG, Hall MD, Lee K, Pinnock RD, and Scott RH (2002) Gabapentin-mediated inhibition of voltage-activated Ca2+ channel currents in cultured sensory neurones is dependent on culture conditions and channel subunit expression. Neuropharmacology 42:353-366

  • ↵34. Sutton KG, Martin DJ, Pinnock RD, Lee K, and Scott RH (2002) Gabapentin inhibits high-threshold calcium channel currents in cultured rat dorsal root ganglion neurones. Br J Pharmacol 135:257-265

  • ↵35. Mori Y, Nishida M, Shimizu S, Ishii M, Yoshinaga T, Ino M, Sawada K, and Niidome T (2002) Ca2+ channel α1B subunit (Cav2.2) knockout mouse reveals a predominant role of N-type channels in the sympathetic regulation of the circulatory system. Trends Cardiovasc Med 12:270-275

  • ↵36. Beuckmann CT, Sinton CM, Miyamoto N, Ino M, and Yanagisawa M (2003) N-type calcium channel α1B subunit (CaV2.2) knock-out mice display hyperactivity and vigilance state differences. J Neurosci 23:6793-6797

  • ↵37. Ghasemzadeh MB, Pierce RC, and Kalivas PW (1999) The monoamine neurons of the rat brain preferentially express a splice variant of α1B subunit of the N-type calcium channel. J Neurochem 73:1718-1723

  • ↵38. Pan JQ and Lipscombe D (2000) Alternative splicing in the cytoplasmic II-III loop of the N-type Ca channel α1B subunit: functional differences are beta subunit-specific. J Neurosci 20:4769-4775

  • ↵39. Lin Y, McDonough SI, and Lipscombe D (2004) Alternative splicing in the voltage-sensitive region of N-type CaV2.2 channels modulates channel kinetics. J Neurophysiol 92:2820-2830

  • ↵40. Lin Z, Haus S, Edgerton J, and Lipscombe D (1997) Identification of functionally distinct isoforms of the N-type Ca2+ channel in rat sympathetic ganglia and brain. Neuron 18:153-166

  • ↵41. Lin Z, Lin Y, Schorge S, Pan JQ, Beierlein M, and Lipscombe D (1999) Alternative splicing of a short cassette exon in a1B generates functionally distinct N-type calcium channels in central and peripheral neurons. J Neurosci 19:5322-5331

  • ↵42. Bell TJ, Thaler C, Castiglioni AJ, Helton TD, and Lipscombe D (2004) Cell specific alternative splicing increases calcium current density in the pain pathway. Neuron 42:127-138

  • ↵43. Rettig J, Sheng ZH, Kim DK, Hodson CD, Snutch TP, and Catterall WA (1996) Isoform-specific interaction of the a1A subunits of brain Ca2+ channels with the presynaptic proteins syntaxin and SNAP-25. Proc Natl Acad Sci USA 93:7363-7368

  • ↵44. Maximov A, Sudhof TC, and Bezprozvanny I (1999) Association of neuronal calcium channels with modular adaptor proteins. J Biol Chem 274:24453-24456

  • ↵45. Kaneko S, Cooper CB, Nishioka N, Yamasaki H, Suzuki A, Jarvis SE, Akaike A, Satoh M, and Zamponi GW (2002) Identification and characterization of novel human CaV2.2 (alpha 1B) calcium channel variants lacking the synaptic protein interaction site. J Biol Chem 22:82-92