The Role of Ion Channels in Neurodegeneration

Phyllis Dan, Ph.D.

Neurodegenerative diseases take an enormous toll on society as well as on individuals. Very limited treatments for these diseases exist, since their molecular mechanisms are not well understood. Several ion channels, a group of membrane spanning proteins that regulate ion content and membrane potential in cells, have been implicated as important

2+ players in these diseases. While many Ca conducting channels (CaV, P2X or glutamate receptors) may contribute to glutamate overload and excitotoxicity directly, K+ channels often regulate the membrane potential controlling the Ca2+ signal indirectly. Below, we review the use of Alomone Labs' products in research related to the role ion channels play in these diseases.

Sodium, potassium, and calcium channels, as well receptors from the basal forebrain cholinergic the these currents in a drosophila model, specific 7 as the glutamate receptors NMDA and AMPA have neurons (BCFN) , whose numbers are shown to blocker of the Kv4.2 channel, Phrixotoxin-2 all been implicated in various neurodegenerative decrease early in the disease process. In addition, (#P-700) and specific blocker of the Shaker

diseases. One of the main factors in neurotoxicity potassium channels, specifically Kv3.1 and Kv2.1 channel α-Dendrotoxin (#D-350) were used. is glutamate overload.1 Glutamate is the primary have been implicated. Immunohistochemical Treatment of cells with amyloid peptide altererd

excitory neurotransmittor of the nervous system. techniques, using Anti-Kv3.1 antibody (#APC-014) the kinetics of the current and caused a decrease 9 Following glutamate release, postsynaptic and Anti-Kv2.1 antibody (#APC-012) were used in neuronal viability. Glutamate toxicity has responses occur through both metabotropic to investigate the expression of these channels and ionotropic receptors. However, in 1957, and both were found to be expressed in the excess glutamate was shown to be toxic. The BCFN.7 Basal forebrain neurons are susceptible term “excitoxicity” was coined to represent to changes associated with aging and related the neurotoxicity caused by excess of excitory disfunctions, such as Alzheimer’s. The neurotransmitters.2 It is now well accepted that involvement of the smooth endoplasmic reticulum Membrane Localization of Kv1.3 in a strong relationship exists between excessive (SER) was investigated using the SER Ca2+ uptake Ca2+ influx and glutamate-triggered neuronal blocker, Thapsigargin (#T-650), however it was Rat Microglial Cultures injury.3 The NMDA receptor in particular has not found to mediate the age-related changes.6 been implicated in this process4 as well as the P2X7 receptor. P2X7 receptors are localized to The accumulation of plaques of amyloid beta (a the excitatory terminals in the hippocampus, as peptide of 39–43 amino acids) is a hallmark of shown by immunohistochemistry using Anti-P2X7 the disease and much effort has been expended antibody (#APR-004).5 Calcium overload can to understand how these plaques interfere in trigger many downstream neurotoxic cascades the normal functioning of the brain. It has been including activation of proteases, protein kinases, suggested that these amyloid plaques form nitric oxide synthesase, calcineurins, which calcium-conducting ion channels that cause rapid leads to increased production of toxin-reactive neurodegeneration due to calcium overload.8 In oxygen species, alteration in the cytoskelton, addition, the plaques have been postulated to mitochondrial dysfunction, and activation interfere with neuronal signaling via the nicotinic of genetic signals leading to cell death.1 The acetylcholine receptor in the early stages of the pervasive involvement of Ca2+ in neuronal function disease.7 The stimulatory effect of amyloid beta suggested that altered Ca homostasis may be a was partiallly dependent on voltage gated Ca2+ Representative confocal immunofluorescence images of rat fundamental mediator of age related changes in channels at low concentrations, as shown by microglia showing colocalization of the membrane-delimited the nervous system.6 the ability of a mixture of Ca2+ channel blockers, marker, OX-42, with Kv1.3. OX-42 primary antibody was used ω-Agatoxin-TK (#A-530), ω-Conotoxin MVIIC with a biotinylated secondary antibody and FITC-conjugated

Alzheimer’s disease is a progressive, (#C-150) and ω-Conotoxin GVIA (#C-300) to streptavidin (green labeling), and Anti-Kv1.3 (#APC-002) neurodegenerative disease characterized by partially attenuate increases in Ca2+ concentration primary antibodies were used with a Cy3-conjugated loss of function and death of nerve cells in in isolated hippocampal nerve endings in the secondary antibody (red labeling). For each cell, the same several areas of the brain, leading to loss of rat.7 A-type K+ channels have been implicated in confocal plane was used for acquisition, thus colocalization mental functions such as memory and learning. the onset of LTP in mammalian neurons, which of channel and microglial membrane is represented by yellow It is the most common cause of dementia. The is thought to underlie learning and memory, regions in the merged images. Adapted from Ref. # 11, with the kind permission of Dr. L.C. neurodegeneration in Alzheimer’s disease is which are progresssively impaired in Alzheimer’s Schlichter of the Toronto Western Hospital and the Am. J. postulated to involve the loss of acetylcholine disease. To determine which channels underlie Physiol. Cell. Physiol.

14 Modulator No.22 Fall 2008 www.alomone.com also been postulated, as the NMDA receptor speech and visual disturbances. MS is the most demyelination may, in fact, be heavily dependent antagonist, memantine, has been approved for common neurological cause of disability in young upon the changes in ion channels.17 It has been the treatment of Alzheimer’s.10 16 adults in industrialized societies. Recent studies suggested that KV3.1b interferes with conduction 18 have identified changes in the expression pattern in demyelination axons. The presence of KV3.1b Damage by reactive oxygen species caused by + of specific Na channel isoforms as an important in CNS nodes has been shown using Anti-KV3.1b the activation of microglia has been documented contributor to remission and progression in MS, antibody (#APC-014). The expression of Kv1.3 in + in Alzheimer’s disease. Several K channels have and there is evidence suggesting that aberrantly postmortem MS brain tissue has been shown been shown to be involved in this respiratory expressed Na+ channels might also contribute by immunohistochemical analysis and confocal burst by blocking current in cultured rat glia to cerebellar dysfunction in MS.16 Changes microscopy using Anti- K 1.3 antibody.19 EAE using the specific K+ channel blocker rAgitoxin-2 v that have, in the past, been attributed to the is widely used experimental model for MS. In (#RTA-420).11 Blockage of the respiratory burst by rAgitoxin-2 further demonstrated the involvement of K+ channels. Western blot analysis of microglial lysates using Anti-KV1.3 antibody (#APC-002) Anti-K 1.5 antibody (#APC-004) and Anti-K 2.3 V Ca Immunohistochemical Staining of Kv1.3 in Human MS Brain antibody (#APC-103) and confocal imaging corroborated these findings. Kv1.3 blockers rCharybdotoxin (#RTC-325), rAgitoxin-2 and α-Dendrotoxin reduce neuron killing by microglia as shown by TUNEL analysis of neurons treated by 12 activated microglia. Kca3.1 is highly expressed in microglia, as shown by immunobloting with Anti-

Kca3.1 antibody (#APC-034) and has been shown to be a possible therapeutic target in acute and chronic neurodegenerative disorders.13

Famial amyloidotic polyneuropathy (FAP) is a neurodegenerative disease that occurs in the PNS and is characterized by extracellular deposition of amyloid fibrils composed of misfolded transthyretin (TTR). The disruption of Ca2+ homostasis by TTR thru N-type Ca2+ channels has been proposed as the mechanism for its cytotoxicity based on the finding that the specific blocker, Conotoxin GVIA significantly reduced the TTR-induced increased in internal Ca2+concentration.14

Amyotrophic Lateral Sclerosis (ALS) is a chronic, progressive disease marked by gradual degeneration of the nerve cells in the central nervous system that control voluntary muscle movement. The disorder causes muscle weakness and atrophy. The cause is unknown, and there is no known cure. It has been found that the motoneurons which innervate tongue muscles are vunerable to degeneration in ALS and this is linked to the differential expression of voltage activated Ca2+ channels.15 It was found that Immunohistochemical staining of K 1.3 in human MS brain floating sections using Anti-K 1.3 there is a 3.5 fold greater expression of P/Q type v v antibody (#APC-002). Confocal microscopy of K 1.3 and CD3/CD4 in MS brain tissue. Confocal current in these motoneurons as opposed to v microscopic images of 20-µm floating sections of postmortem MS brain tissue. (A and B) those which ennervate extraocular muscles as Parenchymal infiltrate with positive CD3 and punctate Kv1.3 staining in the membrane. (C)A cluster was shown by immunolabelling using Anti-Cav2.1 - of lymphocytes stained positively for Kv1.3 and CD4, as well as occasional CD8 (Inset). (D) CD3 cells antibody (#ACC-001). Identity of the channels showed extensive Kv1.3 and CD3 colocalization in the membrane. Immunofluorescent staining of was confirmed by determining the sensitivity PB-derived T cells concentrated on a slide by cytospin showed membrane patterns of staining of 2+ - - - of the Ca currents to channel blockage using CD4, CD8, and Kv1.3. (E) Day 7-activated naive and TCM are CD4 , CCR7 (data not shown) and Kv1.3 . - - the N-type blocker ω-ContoxinGVIA and the P/Q (F) Chronically stimulated resting TEM were CD4 , CCR7 (data not shown) and expressed Kv1.3 in blocker ω-Agatoxin-TK. the membrane but with minimal colocalization with CD4. (G) TEM that had been recently activated

expressed increased amounts of Kv1.3 and demonstrated more colocalization with CD4 similar to the brain tissue lymphocyte in D. (H) Naive CD8- T cells expressed no K 1.3 but, when chronically Multiple sclerosis (MS) is a chronic degenerative v stimulated and activated (I), exhibited intense K 1.3 expression and colocalization with CD8. (J) disease of the central nervous system in which v Isotype controls using nonspecific rabbit primary antibody followed by usual secondary label and gradual destruction of myelin occurs in patches with primary rabbit anti-human and nonspecific labeled mouse anti-rabbit secondary antibody throughout the brain or spinal cord (or both), showed no background staining. interfering with the nerve pathways and causing Adapted from Reference #19, with the kind permission of Dr.Calabresi of the Pathogy Department, muscular weakness, loss of coordination and John Hopkins Hospital and the Proc. Natl. Acad. Sci. USA.

15 Modulator No.22 Fall 2008 www.alomone.com this model it has been shown that cell damage Parkinson’s diseaese (PD) is a slowly progressive neuromuscular disease. It is caused by a mutation does not lead to an increase in endocannoinoid- degenerative disorder of the central nervous in the dystrophin gene, a protein which forms a mediated neuroprotection (as occurs in normal system characterized by slowness or poverty transmembrane complex linking the cytoskelton cells) because of disruption in the functionalilty of movement (bradykinesia), rigidity, postural to extracellular proteins in many tissues. In of P2X7 receptors in the microglia caused instability, and tremor primarily while at rest. dystrophin mutants immunostaining using Anti-

by interferon-gamma. This was shown by Potassium channels have been implicated in the GABAAα1 antibody (#AGA-001) has shown that

immunoprecipitation experiments using Anti- pathogenesis of PD. KATP channels comprised the size and number of GABA receptor clusters are 25 P2X7 antibody (#APR-004) in primary microglia of Kir6.2 and Sur1 are abundantly expressed in decreased at cerebellar inhibitory synapses. cultures. These experiments showed that the substantia nigra dopamine neurons, which are overall expression of the receptors was not the type of neurons that show degradation in Recently, mutations in ion channels have been changed nor was their expression at the plasma Parkinson’s disease.22 GIRK-2 has been shown to shown to play a role in spinocerebellar ataxias. membrane affected. It has been proposed that be linked to the degeneration of dopaminergic Spinocerebellar ataxia (SCA) is one of a group voltage gated Na+ channels can provide a route neurons. Ventral mesencepalic cultures positive of genetic disorders characterized by slowly for Na+ influx into axons which triggers influx for GIRK-2, as shown by immunocytochemistry progressive incoordination of gait and is often 2+ 20 of damaging levels of intra-axonal Ca . The using Anti-Kir3.2 antibody (#APC-006) were more associated with poor coordination of hands, molecular identities of the channels involved has vulnerable to to MPP+-induced neurotoxicity.23 The speech, and eye movements. In SCA13, mutations

been investigated by immunocytochemistry using weaver mutation causes neuronal degradation in Kv3.3 have been shown to have a key role and to

Anti-Nav1.2 antibody (#ASC-002) and Anti-Nav1.6 and severe motor dysfunction caused by antibody (#ASC-009) in the spinal columns of alterations in the inward rectifier channel and EAE mice. A significant increase in the number is often used as a model for PD. A population of

of dymelinated axons demonstrating Nav1.2 granule cells expressed an inwardly-rectifying Expression of Kv1.3 in White and Grey Matter and Nav1.6 staining was shown. Shiverer mice channel which was suggested to be GIRK-2 due to have been widely used as a non-injury model in its sensitivity to QX-314 (#Q-100).24 in Human MS Brain remyelination studies.21 The specific functional

role of Kv1.1 and Kv1.2 in these mice was studied Duchenne muscular dystrophy (DMD) is a form using Dendrotoxin-I (#D-390) and Dendrotoxin-K of muscular dystrophy that is characterized (#D-400). Distribution and changes in expression by decreasing muscle mass and progressive

were studied using Anti-Kv1.1 antibody loss of muscle function in male children.

(#APC-009) and Anti-Kv1.2 antibody (#APC-010). It is the most common congenital human

+ K Channel Blockers Reduce the PMA- Expression of Kv1.3 in Inflammatory Cells in Induced Respiratory Burst in Rat Microglia Human MS Brain

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80

60

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Immunohistochemical staining of Kv1.3 in normal appearing 20 Respiratory Burst white and grey matter in human MS brain using Anti-Kv1.3 antibody (#APC-002). MS brain cryostat sections that were 0 (% of PMA-induced control) grossly uninvolved were examined for Kv1.3 expression. (A)

Kv1.3 deposits were found on perivascular and parenchymal apamin inflammatory cells in the normal appearing white matter. agitoxin-2 Clotrimazole (B) Many of these cells stained positively for CD68. (C) K 1.3 Charybdotoxin v Immunohistochemical staining of Kv1.3 in inflammatory cells staining was also seen on parenchymal cells in the gray

Microglia were incubated in 2 mM DHR 123 and the in human MS braining using Anti-Kv1.3 antibody (#APC-002). matter. (D) Phosphorylated neurofilament staining showed fluorescence monitored for 5 min to ensure a stable Paraffin sections were stained by indirect immunoperoxidase axonal fragmentation and swelling in a normal appearing + baseline. A K channel blocker was perfused into the bath, for Kv1.3, CD3, CD4, CCR7, and CCR5. Areas used in gray matter area, which was a consecutive section for the

the fluorescence recorded continuously for a further 5 min, sectioning were from a white matter plaque. There were many Kv1.3 staining seen only on inflammatory cells in C. (E) then the bath was perfused with the blocker plus 100 nM perivascular inflammatory cells that stained positively for Some of the cells were branched process bearing cells with

PMA. The fluorescence signal from several cells in each field CD3 (A), Kv1.3 (B), and CD4 (B Inset) on consecutive sections. an appearance suggestive of microglia. (F) Double labeling - - was monitored for a further 45 min, and the final average (C) Kv1.3 was also localized on inflammatory cells in the white identified some Kv1.3 cells as CD68 cells (arrows red-

value compared with control cells from the same batches matter parenchyma (Inset reveals membrane polarization Kv1.3, dark brown CD68); not all CD68 cells expressed Kv1.3

(number of cells from at least 3 rat litters indicated). The of Kv1.3 staining). (D) Consecutive sections through another (arrowheads). (G) Double labeling with CD3 (dark brown) and - drug concentrations were 50 nM rCharybdotoxin (#RTC-325), perivascular infiltrate revealed numerous Kv1.3 inflammatory Kv1.3 (red) was also clearly seen. Not all Kv1.3- expressing 5 nM rAgitoxin-2 (#RTA-420), 1.2 nM Apamin, and 500 nM cells, which were predominantly CCR7- (E) (Inset reveals rare cells are CD68 positive. (H) Control of the immunoperoxidase Clotrimazole. *P , 0.05 and **P , 0.001,values significantly CCR7 positive staining), and CCR5- (F). (Scale bar, 50 µm in A reaction. (Scale bar, 20 µm in A, B, D, G, and H; 50 µm in C different from controls. and B and 20 µm in C, D, E, and F.) and F; and 10 µm in E.) Adapted from Ref. # 11, with the kind permission of Dr. L.C. Adapted from Reference #19, with the kind permission Adapted from Reference #19, with the kind permission Schlichter of the Toronto Western Hospital and the Am. J. of Dr.Calabresi of the Pathogy Department, John Hopkins of Dr.Calabresi of the Pathogy Department, John Hopkins Physiol. Cell. Physiol. Hospital and the Proc. Natl. Acad. Sci. USA. Hospital and the Proc. Natl. Acad. Sci. USA.

16 Modulator No.22 Fall 2008 www.alomone.com alter the channel properties, leading to a change Anti-Cav1.2a (α1C Cardiac)______ACC-013 Anti-GABA (A) α3______AGA-003 Anti-Ca 1.3 (α1D )______ACC-005 Anti-GABA (A) α6______AGA-004 in the firing patterns of neurons, explaining the v Anti-Ca 2.3 (α1E )______ACC-006 Anti-GABA(A) γ2______AGA-005 physiological manifestations of the disease.26 In v Anti-Cav3.1 (α1G )______ACC-021 Anti-P2X1______APR-001 a different type of ataxia, SCA63, a degenerative Anti-Cav3.2 (α1H )______ACC-025 Anti-P2X2______APR-003 disorder of the cerebellum characterized by Anti-Cav3.3 (α1I )______ACC-009 Anti-P2X3______APR-016 Anti-Ca pan α1______ACC-004 Anti-P2X4______APR-002 nearly selective and progressive death of Purknje v cells, the mutation is in the α1A subunit of Anti-P2X5______APR-005 Antibodies to Voltage-Gated Na+ Channels Anti-P2X7______APR-004 the neuronal P/Q-type voltage-gated calcium Anti-Nav1.1______ASC-001 channel.27 This mutation leads to an expanded 2+ Anti-Nav1.2______ASC-002 Voltage-Gated Ca Channel Blockers region of glutamine residues that shifts the Anti-Nav1.3______ASC-004 ω-Agatoxin IVA______A-500 Anti-Na 1.4______ASC-020 ω-Agatoxin TK______A-530 voltage dependence of channel activation and v Anti-Na 1.5______ASC-005 Calcicludine______C-650 rate of inactivation and impairs normal G-protein v Anti-human Na 1.5______ASC-013 Calciseptine______C-500 regulation of P/Q channels. Using the specific v Anti-Nav1.6______ASC-009 ω-Conotoxin GVIA______C-300 antibody Anti-Cav2.1 antibody has been shown Anti-Nav1.7______ASC-008 ω-Conotoxin MVIIA______C-670 that this pathological expansion can be expressed Anti-Nav1.8______ASC-016 ω-Conotoxin MVIIC______C-150

Anti-Nav1.9______ASC-017 FS-2______F-700 in multiple isoforms of the Cav2.1 subunit. Anti-Pan Nav______ASC-003 ω-Grammotoxin SIA______G-450 Anti-Naβ2______ASC-007 PLTX-II______P-510 An important aspect of these findings is SNX-482______S-500 that the underlying mechanisms for many Antibodies to Voltage Activated K+ Channels TaiCatoxin______T-800 Anti-K 1.1______APC-009 neurodegenerative diseases was thought to v Anti-K 1.2______APC-010 K+ Channel Blockers lie in accumulation of misfolded, aggregated v Anti-K 1.3______APC-002 rAa1______RTA-400 proteins; the involvement of ion channels in v Anti-Kv1.3 (extracellular)______APC-101 rAgitoxin-1______RTA-150 neurodegenerative disease upons up a whole new Anti-Kv1.3 (extracellular)-FITC______APC-101-F rAgitoxin-2______RTA-420 17 avenue of theurapeutic possibilities. Anti-Kv1.4______APC-007 rAgitoxin-3______RTA-390

Anti-Kv1.5______APC-004 Apamin______A-200

Anti-Kv1.6______APC-003 BDS-I______B-400

Anti-Kv1.7______APC-063 BDS-II______B-450

Anti-Kv2.1______APC-012 rBeKm-1______RTB-470 Anti-K 2.2______APC-120 rCharybdotoxin______RTC-325 References: v Anti-Kv3.1b______APC-014 α-Dendrotoxin______D-350 Anti-K 3.2______APC-011 β-Dendrotoxin______D-360 1. Arundine, M. and Tymianski, M. (2004) Cell. Mol. Life Sci. 61, 657. v Anti-Kv3.3______APC-102 γ-Dendrotoxin______D-370 2. Olney, J.W. (1969) Science 164, 719. Anti-Kv3.4______APC-019 δ-Dendrotoxin______D-380 3. Cho, D.W. (1988) Trends Neurosci. 11, 465i. Anti-Kv4.1______APC-119 Dendrotoxin-I______D-390 4. Tapia, R. et al. (1999) Neurochem. Int. 34, 23. Anti-Kv4.2______APC-023 Dendrotoxin-K______D-400 5. Sperlagh, B. et al. (2002) J. Neurochem. 81, 1196. Anti-Kv4.3______APC-017 E-4031______E-500

6. Murchison, D. and Griffith, W. H. (1998) J. Neurophysiol. 80, 350. Anti-Kv7.1 (KCNQ1)______APC-022 rErgtoxin-1______RTE-450

7. Dougherty, J.J. et al. (2003) J. Neurosci. 23, 6740. Anti-Kv7.2 (KCNQ2)______APC-050 rHeteropodatoxin-2______RTH-340 Anti-K 7.3 (KCNQ3)______APC-051 rHongotoxin-1______RTH-400 8. Betancourt, L. and Colom, L.V. (2000) J. Neurosci. Res. 61, 646. v Anti-K 10.1 (EAG-1)______APC-104 rIberiotoxin______RTI-400 9. Kidd, J. F. et al. (2006) J. Neurobiol. 66, 476. v Anti-KV10.2 (EAG-2)______APC-053 rKaliotoxin-1______RTK-370 10. Lipton, S. (2004) NeuroRx 1,101. Anti-K 11.1 (erg1)______APC-016 rLq2______RTL-550 11. Khanna, et al. (2001) Am. J. Physiol. Cell. Physiol. 280, C796 v Anti-hKv11.1 (HERG)______APC-062 MCD-Peptide______M-250 12. Fordyce, C. B. et al. (2005) J. Neurosci. 25, 7139. Anti-Kv11.1 (HERG) (extracellular)______APC-109 rMargatoxin______RTM-325 13. Kaushal, V. et al. (2007) J. Neurosci. 27, 234. Anti-Kv11.1 (HERG) (extracellular) FITC______APC-109-F rMaurotoxin______RTM-340 14. Hou, X. et al. (2007) J. Neurochem. 100, 446. Anti-Kv11.2 (erg2)______APC-114 rNoxiustoxin______RTN-340

15. Miles, G. B. et al. (2004) Eur. J. Neurosci. 20, 903. Anti-Kv11.3 (erg3)______APC-112 rOsK-1______RTO-150

16. Waxman, S.G. (2006) Nat. Rev. Neurosci. 7, 932. Anti-Kv12.1 (Elk1)______APC-113 Paxilline______P-450 17. Gutmann, L. and Gutmann, L. (1996) Neurology 47, 18. Penitrem A______P-650 2+ + Phrixotoxin-2______P-700 18. Devraux, J. et al. (2003) J. Neurosci. 23, 4509. Antibodies to Ca Activated K Channels Anti-K 1.1 (1098-1196)______APC-021 Stromatoxin-1 (rScTx-1)______RTS-350 19. Rus, H. et al. (2005) Proc. Natl. Acad. Sci. USA 102, 11094. Ca Anti-K 1.1 (1184-1200)______APC-107 rScyllatoxin______RTS-370 20. Craner, M. J. et al. (2004) Brain, 127, 294. Ca Anti-KCa2.1______APC-039 rSlotoxin______RTS-410 21. Sinha, K. et al. (2006) J. Neurophysiol. 95, 1683 Anti-KCa2.2______APC-028 Stichodactyla Toxin (ShK)______S-400 22. Liss, B. et al. (2005) Nat. Neurosci. 8, 1742. Anti-KCa2.3 (N-term)______APC-025 rTamapin______RTT-400 23. Chung, C. Y. et al. (2005) Hum. Mol. Genet. 14, 1709 Anti-KCa2.3 (C-term)______APC-103 rTertiapin______RTT-250 24. Rossi, P. et al. (1998) J. Neurosci. 18, 3545 Anti-KCa3.1______APC-064 rTertiapin-Q______RTT-170 25. Grady, R. M. et al. (2006) J. Neurosci. 26, 2841. rTityustoxin Kα______RTT-360 + 26. Waters, M.F. et al. (2006) Nat. Genet. 38, 447. Antibodies to Inward Rectifier K Channels Verruculogen______V-500 Anti-K 1.1______APC-001 27. Restituito, S. et al. (2000) J. Neurosci. 20, 6394. ir 2+ Anti-Kir2.1______APC-026 Intracellular Ca Mobilizers

Anti-Kir2.2______APC-042 A23187______A-600

Anti-Kir2.3______APC-032 Anhydroryanodine______A-510

Anti-Kir3.1______APC-005 Cyclopiazonic Acid______C-750

Anti-Kir3.2______APC-006 Imperatoxin A______I-300 Anti-K 3.3______APC-038 rMaurocalcine______RTM-100 Related Products ir Anti-Kir3.4______APC-027 Ochratoxin A______O-400

Compound Product # Anti-Kir4.1______APC-035 Ryanodine______R-500

Anti-Kir4.2______APC-058 tBuBHQ______T-220 Antibodies to Voltage-Gated Ca2+ Channels Anti-Kir6.1______APC-105 Thapsigargin______T-650 Anti-Ca 2.1 (α1A)______ACC-001 v Anti-Kir6.2______APC-020 Thapsigargin Epoxide______T-670

Anti-Cav2.2 (α1B)______ACC-002 2+ Anti-Cav1.2 (α1C)______ACC-003 Antibodies to Ligand-Gated Channels Ca Ionophores

Anti-Cav1.2-ATTO-488______ACC-003-AG Anti-GABA (A) α1______AGA-001 A23187______A-600

Anti-human Cav1.2 (α1C )______ACC-022 Anti-GABA (A) α2______AGA-002 Ionomycin______I-700

17 Modulator No.22 Fall 2008 www.alomone.com