INFLUENCE OF FORMAMIDINES ON BATRACHOTOXIN IN A 20-ALPHA-BENZOATE BINDING TO NEURAL MEMBRANES FROM PYRETHROID SUSCEPTIBLE AND RESISTANT TOBACCO BUDWORM MOTHS HELIOTHIS-VIRESCENS
Cj. Church et al., INFLUENCE OF FORMAMIDINES ON BATRACHOTOXIN IN A 20-ALPHA-BENZOATE BINDING TO NEURAL MEMBRANES FROM PYRETHROID SUSCEPTIBLE AND RESISTANT TOBACCO BUDWORM MOTHS HELIOTHIS-VIRESCENS, Comparative biochemistry and physiology. C. Comparative pharmacologyand toxicology, 105(3), 1993, pp. 443-449
1. Amitraz stimulated [H-3]batrachotoxin in A 20-alpha-benzoate ([H-3]
BTX-B) binding to neural membranes from pyrethroid susceptible (S) and
resistant (R) tobacco budworm moths, but N'-(2,4-xylyl)-N-methylforma
midine (SN 49844) stimulated binding only with S moths. 2. Chlordimefo
rm stimulated [H-3]BTX-B binding only with R moths, and N'-(4-chloro-o
-tolyl)-N-methylformamidine (demethylchlordimeform) yielded no signifi
cant stimulation with either strain. 3. A mixture of amitraz and delta
methrin, a pyrethroid that previously had been shown to enhance [H-3]B
TX-B binding with tobacco budworm moths, also gave significant stimula
tion of radioligand binding with S moths. 4. When membranes were prepa
red from S moths at various intervals following topical application of
amitraz, deltamethrin, or a mixture of amitraz and deltamethrin, biph
asic stimulation of [H-3]BTX-B binding was observed, with maximum enha
ncement occurring at 2 and 6 hr. 5. These results provided a basis for
suggesting that a formamidine binding site is located on or closely a
ssociated with the sodium channel protein. 6. Whether this site is the
same as the pyrethroid/DDT binding domain remains to be demonstrated;
however, similarities in responses elicited by amitraz and deltamethr
in alone and in combination indicate that some relationship may exist.