Binding of [3H]batrachotoxinin A-20-alpha-benzoate to a high affinity site associated with house fly head membranes.
Comp Biochem Physiol C Comp Pharmacol Toxicol
; 94(1): 255-60, 1989.
Article
en En
| MEDLINE
| ID: mdl-2576735
1. [3H]Batrachotoxinin A-20-alpha-benzoate (BTX-B), a radioligand that labels the alkaloid activator recognition site of the voltage-sensitive sodium channel, was bound specifically to high affinity, saturable sites in a subcellular preparation from house fly (Musca domestica L.) heads that was shown previously to contain binding sites for other sodium channel-directed ligands. 2. Specific binding of [3H]BTX-B was observed in the presence of 140 mM sodium or potassium and was inhibited by choline ion. 3. Saturating concentrations of scorpion (Leiurus quinquestriatus) venom stimulated the specific binding of [3H]BTX-B four-fold, increasing the proportion of specific binding of 10 nM [3H]BTX-B from less than 15% to 40%. Equilibrium dissociation studies in the presence of scorpion venom gave an equilibrium dissociation constant (KD) for [3H]BTX-B of 80 nM and a maximal binding capacity (Bmax) of 1.5 pmol/mg protein. 4. Parallel experiments in the absence of venom gave a KD value of 140 nM and a Bmax of 1.3 pmol/mg protein, indicating that scorpion venom stimulated [3H]BTX-B binding by increasing the affinity of this site approximately two-fold. 5. The specific binding of [3H]BTX-B was inhibited by the sodium channel activators aconitine and batrachotoxin and, to a lesser extent, by the anticonvulsant diphenylhydantoin. However, several other sodium channel-directed neurotoxins known to exert allosteric effects on the binding of [3H]BTX-B to mammalian brain preparations did not affect the binding of [3H]BTX-B to house fly head membranes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Batracotoxinas
/
Receptores Colinérgicos
/
Moscas Domésticas
/
Neurotoxinas
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
Comp Biochem Physiol C Comp Pharmacol Toxicol
Año:
1989
Tipo del documento:
Article
Pais de publicación:
Reino Unido