PMID- 8071852
OWN - NLM
STAT- MEDLINE
DCOM- 19940928
LR  - 20141120
IS  - 0022-3565 (Print)
IS  - 0022-3565 (Linking)
VI  - 270
IP  - 2
DP  - 1994 Aug
TI  - Differential mechanism of action of the pyrethroid tetramethrin on 
      tetrodotoxin-sensitive and tetrodotoxin-resistant sodium channels.
PG  - 595-603
AB  - Rat dorsal root ganglion neurons are endowed with tetrodotoxin-sensitive(TTX-S) 
      and tetrodotoxin-resistant (TTX-R) sodium channels. The pyrethroid insecticides, 
      which are known to keep sodium channels open for a prolonged period of time, 
      cause differential effects on the two types of sodium channels. The whole-cell 
      patch clamp experiments were performed with rat dorsal root ganglion neurons in 
      primary culture. In TTX-S sodium channels, the slow sodium current during step 
      depolarization was increased somewhat by tetramethrin, and a tail sodium current 
      with a slowly rising and falling phase appeared upon repolarization. The tail 
      current developed even after the sodium current during depolarization had 
      subsided. In TTX-R sodium channels, the slow sodium current during step 
      depolarization was increased markedly by tetramethrin, and upon repolarization a 
      large instantaneous tail current was generated and decayed slowly. The 
      steady-state sodium channel inactivation curve was shifted by tetramethrin in the 
      hyperpolarizing direction in both TTX-S and TTX-R channels. The sodium 
      conductance-voltage curve also was shifted by tetramethrin in the hyperpolarizing 
      direction in both TTX-S and TTX-R channels, and the latter was affected more 
      strongly than the former. At a concentration of 10 microM, the highest 
      concentration tested, tetramethrin modified only 12% of the TTX-S sodium 
      channels, whereas the modification was as high as 81% in the TTX-R. Even at 10 
      nM, 1.3% of TTX-R sodium channels were modified; this accounts for the high 
      potency of tetramethrin as an insecticide.(ABSTRACT TRUNCATED AT 250 WORDS)
FAU - Tatebayashi, H
AU  - Tatebayashi H
AD  - Department of Pharmacology, Northwestern University Medical School, Chicago, 
      Illinois.
FAU - Narahashi, T
AU  - Narahashi T
LA  - eng
GR  - NS14143/NS/NINDS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Pharmacol Exp Ther
JT  - The Journal of pharmacology and experimental therapeutics
JID - 0376362
RN  - 0 (Insecticides)
RN  - 0 (Pyrethrins)
RN  - 0 (Sodium Channels)
RN  - 4368-28-9 (Tetrodotoxin)
RN  - Z72930Q46K (tetramethrin)
SB  - IM
MH  - Animals
MH  - Drug Resistance
MH  - In Vitro Techniques
MH  - Insecticides/*pharmacology
MH  - Membrane Potentials/drug effects
MH  - Neurons/drug effects
MH  - Pyrethrins/*pharmacology
MH  - Rats
MH  - Sodium Channels/*drug effects
MH  - Tetrodotoxin/*pharmacology
EDAT- 1994/08/01 00:00
MHDA- 1994/08/01 00:01
CRDT- 1994/08/01 00:00
PHST- 1994/08/01 00:00 [pubmed]
PHST- 1994/08/01 00:01 [medline]
PHST- 1994/08/01 00:00 [entrez]
PST - ppublish
SO  - J Pharmacol Exp Ther. 1994 Aug;270(2):595-603.