PMID- 17618665
OWN - NLM
STAT- MEDLINE
DCOM- 20071109
LR  - 20070911
IS  - 0041-0101 (Print)
IS  - 0041-0101 (Linking)
VI  - 50
IP  - 4
DP  - 2007 Sep 15
TI  - Characterization of the excitatory mechanism induced by Jingzhaotoxin-I 
      inhibiting sodium channel inactivation.
PG  - 507-17
AB  - We have recently isolated a peptide neurotoxin, Jingzhaotoxin-I (JZTX-I), from 
      Chinese tarantula Chilobrachys jingzhao venom that preferentially inhibits 
      cardiac sodium channel inactivation and may define a new subclass of spider 
      sodium channel toxins. In this study, we found that in contrast to other spider 
      sodium channel toxins acting presynaptically rather than postsynaptically, JZTX-I 
      augmented frog end-plate potential amplitudes and caused an increase in both 
      nerve mediated and unmediated muscle twitches. Although JZTX-I does not 
      negatively shift sodium channel activation threshold, an evident increase in 
      muscle fasciculation was detected. In adult rat dorsal root ganglion neurons 
      JZTX-I (1 microM) induced a significant sustained tetrodotoxin-sensitive (TTX-S) 
      current that did not decay completely during 500 ms and was inhibited by 0.1 
      microM TTX or depolarization due to voltage-dependent acceleration of toxin 
      dissociation. Moreover, JZTX-I decreased closed-state inactivation and increased 
      the rate of recovery of sodium channels, which led to an augmentation in TTX-S 
      ramp currents and decreasing the amount of inactivation in a use-dependant 
      manner. Together, these data suggest that JZTX-I acted both presynaptically and 
      postsynaptically and facilitated the neurotransmitter release by biasing the 
      activities of sodium channels towards open state. These actions are similar to 
      those of scorpion alpha-toxin Lqh II.
FAU - Xiao, Yucheng
AU  - Xiao Y
AD  - Life Sciences College, Hunan Normal University, Changsha, Hunan 410081, PR China.
FAU - Li, Jiang
AU  - Li J
FAU - Deng, Meichun
AU  - Deng M
FAU - Dai, Changliang
AU  - Dai C
FAU - Liang, Songping
AU  - Liang S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20070503
PL  - England
TA  - Toxicon
JT  - Toxicon : official journal of the International Society on Toxinology
JID - 1307333
RN  - 0 (Peptides)
RN  - 0 (Sodium Channel Blockers)
RN  - 0 (Spider Venoms)
RN  - 0 (jingzhaotoxin-I, Chilobrachys jingzhao)
RN  - 4368-28-9 (Tetrodotoxin)
SB  - IM
MH  - Action Potentials/drug effects
MH  - Animals
MH  - Female
MH  - Ganglia, Spinal/drug effects/physiology
MH  - Ion Channel Gating/drug effects
MH  - Male
MH  - Mice
MH  - Motor Endplate/physiology
MH  - Neuromuscular Junction/drug effects
MH  - Peptides/*pharmacology
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Sodium Channel Blockers/*pharmacology
MH  - Spider Venoms/*pharmacology
MH  - Synaptic Transmission/drug effects
MH  - Tetrodotoxin/pharmacology
EDAT- 2007/07/10 09:00
MHDA- 2007/11/10 09:00
CRDT- 2007/07/10 09:00
PHST- 2007/02/11 00:00 [received]
PHST- 2007/04/15 00:00 [revised]
PHST- 2007/04/23 00:00 [accepted]
PHST- 2007/07/10 09:00 [pubmed]
PHST- 2007/11/10 09:00 [medline]
PHST- 2007/07/10 09:00 [entrez]
AID - S0041-0101(07)00163-8 [pii]
AID - 10.1016/j.toxicon.2007.04.018 [doi]
PST - ppublish
SO  - Toxicon. 2007 Sep 15;50(4):507-17. doi: 10.1016/j.toxicon.2007.04.018. Epub 2007 
      May 3.