Dendrotoxin K
目录号 : GC64863
Dendrotoxin K 是一种 Kv1.1 通道阻滞剂。Dendrotoxin K 通过控制突触前尖峰波以时间依赖性方式将谷氨酸释放入 CA3 神经元中。
Cas No.:119128-61-9
Sample solution is provided at 25 µL, 10mM.
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Quality Control & SDS
- View current batch:
- Purity: >98.00%
- COA (Certificate Of Analysis)
- SDS (Safety Data Sheet)
- Datasheet
Dendrotoxin K is a Kv1.1 channel blocker. Dendrotoxin K determines glutamate release in CA3 neurons in a time-dependent manner through the control of the presynaptic spike waveform[1].
[1]. Bialowas A, et al. Analog modulation of spike-evoked transmission in CA3 circuits is determined by axonal Kv1.1 channels in a time-dependent manner. Eur J Neurosci. 2015 Feb;41(3):293-304.
| Cas No. | 119128-61-9 | SDF | Download SDF |
| 分子式 | C294H462N84O75S6 | 分子量 | 6565.72 |
| 溶解度 | 储存条件 | Store at -20°C | |
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1 mg | 5 mg | 10 mg |
| 1 mM | 0.1523 mL | 0.7615 mL | 1.5231 mL |
| 5 mM | 0.0305 mL | 0.1523 mL | 0.3046 mL |
| 10 mM | 0.0152 mL | 0.0762 mL | 0.1523 mL |
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Effects of alpha-dendrotoxin and Dendrotoxin K on extracellular excitatory amino acids and on electroencephalograph spectral power in the hippocampus of anaesthetised rats
Neurosci Lett 2000 Nov 3;293(3):183-6.PMID:11036191DOI:10.1016/s0304-3940(00)01530-5.
Dendrotoxins, important pharmacological tools for studying K(+) channels, are potently convulsant in the central nervous system and evidence suggests that different members of the dendrotoxin family may act at pre- or post-synaptic sites. Using a combination of intrahippocampal infusion, microdialysis and electroencephalograph (EEG) recording, we have compared the effects of alpha-dendrotoxin and Dendrotoxin K on extracellular levels of excitatory amino acids in anaesthetised rats. Our findings show that although infusion of 35 pmol of both peptides was associated with elevated extracellular aspartate and glutamate, these increased levels were more sustained with Dendrotoxin K. Furthermore, there was EEG evidence of an associated transient functional change consistent with an action on pre-synaptic K(+) channels. In contrast, infusion of alpha-dendrotoxin produced only a brief effect on amino acid levels and no evidence of a functional consequence.
Cloning and functional expression of Dendrotoxin K from black mamba, a K+ channel blocker
Biochemistry 1993 Jun 1;32(21):5692-7.PMID:8504088DOI:10.1021/bi00072a026.
Mamba dendrotoxins, 7K M(r) polypeptides with three disulfide bonds, selectively inhibit certain fast-activating, voltage-sensitive neuronal K+ channels and have been instrumental in their identification, localization, and purification. However, derivatives with more refined specificity are essential to define the structural and functional properties of the multiple subtypes known to reside in the nervous system. Hence, utilizing a constructed cDNA library from the venom glands of the black mamba (Dendroaspis polylepis), the gene encoding Dendrotoxin K was isolated, amplified, and expressed as a maltose-binding fusion protein in the periplasmic space of Escherichia coli. After cleavage of the chaperone from the affinity-purified product, a recombinant protein was isolated and shown to be identical to native Dendrotoxin K in its N-terminal sequence, chromatographic behavior, convulsive-inducing activity, and binding to voltage-activated K+ channels in bovine synaptic membranes. This successful expression of refolded active toxin, in adequate yield, makes possible for the first time the preparation of mutants with specificity tailored for each K+ channel subtype, based both on the recently derived three-dimensional structure of alpha-dendrotoxin and the identified binding site on cloned K+ channels.
Dendrotoxin-sensitive K(+) currents contribute to accommodation in murine spiral ganglion neurons
J Physiol 2002 Aug 1;542(Pt 3):763-78.PMID:12154177DOI:10.1113/jphysiol.2002.017202.
We have previously identified two broad electrophysiological classes of spiral ganglion neuron that differ in their rate of accommodation (Mo & Davis, 1997a). In order to understand the underlying ionic basis of these characteristic firing patterns, we used alpha-dendrotoxin (alpha-DTX) to eliminate the contribution of a class of voltage-gated K(+) channels and assessed its effects on a variety of electrophysiological properties by using the whole-cell configuration of the patch-clamp technique. Exposure to alpha-DTX caused neurons that initially displayed rapid accommodation to fire continuously during 240 ms depolarizing test pulses within a restricted voltage range. We found a non-monotonic relationship between number of action potentials fired and membrane potential in the presence of alpha-DTX that peaked at voltages between -40 to -10 mV and declined at more depolarized and hyperpolarized test potentials. The alpha-DTX-sensitive current had two components that activated in different voltage ranges. Analysis of recordings made from acutely isolated neurons gave estimated half-maximal activation voltages of -63 and 12 mV for the two components. Because alpha-DTX blocks the Kv1.1, Kv1.2 and Kv1.6 subunits, we examined the action of the Kv1.1-selective blocker Dendrotoxin K (DTX-K). We found that this antagonist reproduced the effects of alpha-DTX on neuronal firing, and that the DTX-K-sensitive current also had two separate components. These data suggest that the transformation from a rapidly adapting to a slowly adapting firing pattern was mediated by the low voltage-activated component of DTX-sensitive current with a potential contribution from the high voltage-activated component at more depolarized potentials. In addition, the effects of DTX-K indicate that Kv1.1 subunits are important constituents of the underlying voltage-gated potassium channels.
Seizures and hippocampal damage produced by dendrotoxin-K in rats is prevented by the 21-aminosteroid U-74389G
Exp Neurol 1997 Sep;147(1):204-10.PMID:9294417DOI:10.1006/exnr.1997.6587.
The epileptogenic and neurodegenerative effects of Dendrotoxin K (DTx-K), from Dendroaspis polylepsis, a specific blocker of a noninactivating, voltage-sensitive K+ channel, were studied after focal injection into one dorsal hippocampus in rats pretreated with the 21-aminosteriod U-74389G, a scavenger of free oxygen radicals. Administration of 35 pmol DTx-K elicited in all of the treated animals (n = 6) motor seizures and bilateral electrocortical (ECoG) discharges after a latent period of approximately 5 min. At 24 h, histological examination of brain (n = 6) coronal sections (10 microns; n = 6 per brain) detected bilateral damage to the hippocampal formation. Quantitation of damage revealed significant bilateral neuronal cell loss in the CA1 and CA4 pyramidal cell layer and dentate gyrus granule cell layer relative to the corresponding brain regions of rats (n = 6) injected with bovine serum albumin (300 ng), which per se was ineffective in all respects. DTx-K (35 pmol) also caused a significant loss of CA3 pyramidal neurons ipsilateral to the site of toxin injection. Systemic (i.p.) administration of U-74389G (5 mg/kg given 30 min beforehand) delayed the onset of motor and ECoG seizures and reduced the number of epileptogenic discharges typically observed in rats receiving an injection of DTx-K (35 pmol) alone. Similarly, this treatment prevented the damage inflicted to the hippocampus by the toxin and in no instance was significant neuronal loss observed. At variance with these results, pretreatment with U-74389G (up to 10 mg/kg i.p.) failed to prevent seizures and CA1 hippocampal damage evoked by intra-hippocampal injection of alpha-DTx (35 pmol), a DTx-K homologue which preferentially inhibits a slowly inactivating, voltage-dependent K+ conductance in nerve cells. In conclusion, the present data support a role for free oxygen radicals in mediating hippocampal damage induced by DTx-K, but not alpha-DTx, and confirm the original deduction that these DTx homologues are complementary neurobiological tools to study mechanisms of seizures and neuronal death.
Site-directed mutagenesis of Dendrotoxin K reveals amino acids critical for its interaction with neuronal K+ channels
Biochemistry 1997 Jun 24;36(25):7690-6.PMID:9201909DOI:10.1021/bi963105g.
Dendrotoxin K (DTXK) is a 57-residue protein from mamba venom that blocks certain non-inactivating, voltage-activated K+ currents in neurones. In order to pinpoint the residues responsible for its specificity, structure-activity relations of DTX(K) were investigated by mutagenesis. A previously cloned gene encoding this toxin [Smith et al. (1993) Biochemistry 32, 5692-5697] was used to make single mutations; after expression in Escherichia coli as fusion proteins and enzymatic cleavage of the conjugates isolated from the periplasmic space, nine toxins were purified. Structural analysis of the native DTXK and representative mutants by circular dichroism showed that no significant differences were detectable in their folded structures. The biological activity of the mutants, which contained alterations of positively charged and other amino acids, was determined from their abilities to compete for the binding of 125I-labeled DTX(K) to K+ channels in synaptic plasma membranes from rat cerebral cortex. Mutants with residues substituted in the alpha-helix near the C-terminus (R52A or R53A) yielded binding parameters similar to those of wild-type and native DTX(K). In the case of the beta-turn (residues 24-28), however, altering single amino acids reduced binding to the high-affinity site of K+ channels, with the rank order of decreases being K26A >> W25A > K24A = K28A. Also, substitutions made in the 3(10)-helix (residues 3-7), a region located close to the beta-turn, produced equivalent effects (K3A > K6A). Thus, it is deduced that residues in the distorted beta-turn and neighboring 3(10)-helix of DTX(K) are critical for its interaction with neuronal K+ channels.