The interaction of chlorinated alicyclic insecticides with brain GABA(A) receptors in channel catfish (Ictalurus punctatus).
J Toxicol Environ Health A
; 56(8): 543-53, 1999 Apr 23.
Article
en En
| MEDLINE
| ID: mdl-10321384
ABSTRACT
Chlorinated alicyclic insecticides are believed to antagonize the action of the neurotransmitter gamma-aminobutyric acid (GABA) at its receptor in vertebrates. Binding of the specific GABA(A) receptor ligand [35S]-t-butylbicyclophosphorothionate (TBPS) to channel catfish brain P2 membranes suggested a single population of receptors with a Kd (56.6+/-2.6 nM) and Bmax (2435+/-276 fmol/mg protein) that are similar to published values for other fish species. The competition of several chlorinated compounds for TBPS binding was investigated. The most potent inhibitors of TBPS binding were 12-ketoendrin, photoheptachlor epoxide, photoheptachlor, telodrin, and endrin, respectively, with IC50s of 20-90 nM. Photooxychlordane, photo alpha-chlordane, and oxychlordane were intermediate in potency (122-219 nM), as were isodrin, dihydroisodrin, heptachlor epoxide, and alpha-chlordane, which were similar in potency (311-397 nM). Dieldrin, lindane, and dihydroaldrin were much less potent (592-1103 nM). Heptachlor, aldrin, and gamma-chlordane were weak inhibitors of TBPS binding (2073-2738 nM). Chlordene and chlordecone had the lowest potency of all compounds studied (10,201-21,178 nM) with the exception of mirex, which did not inhibit binding at a concentration of 50 microM. There is a good correlation between binding potency and the available toxicity data for several of these compounds in channel catfish. There is also a good correlation between the inhibitory potency in channel catfish by these types of compounds with that in rats.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ictaluridae
/
Encéfalo
/
Receptores de GABA-A
/
Hidrocarburos Clorados
/
Insecticidas
Límite:
Animals
Idioma:
En
Revista:
J Toxicol Environ Health A
Asunto de la revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Año:
1999
Tipo del documento:
Article
País de afiliación:
Estados Unidos