Suppressive effect of simultaneous injection of ACTH1-10 and beta-endorphin on brain [3H]flunitrazepam binding.
Seven-day hypophysectomized rats were intracerebroventricularly (i.c.v.) injected with beta-endorphin, ACTH1-10 or beta-endorphin+ACTH1-10 (10-20 ng of each compound) and the [3H]flunitrazepam ([3H])FNZ) binding to the rat cerebral cortex of hypophysectomized rats was assayed one hour later. The i.c.v. injection of ACTH1-10 (10-20 ng) or beta-endorphin (10-20 ng) significantly increased [3H]FNZ binding to a similar extent. The effect of i.c.v. injection of ACTH1-10 on brain binding was blunted by simultaneous beta-endorphin administration at the same doses. The i.c.v. naloxone injection (10-20 ng) did not modify the effect of ACTH1-10 (10 ng) on [3H]FNZ binding, but counteracted, in a dose-related manner, the blocking effect of beta-endorphin on ACTH1-10-dependent brain [3H]FNZ binding. The results suggest the existence of an opioid-melanopeptide integration to control brain benzodiazepine receptors.
Gomar
M D
MD
Departamento de Fisiologia, Facultad de Medicina, Universidad de Granada, Spain.
Fernández
B
B
Castillo
J L
JL
del Aguila
C M
CM
Acuña-Castroviejo
D
D
D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D005445:Flunitrazepam / Q000493:pharmacokinetics*; D007016:Hypophysectomy; D066298:In Vitro Techniques; D007276:Injections, Intraventricular; D008297:Male; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism; D001615:beta-Endorphin / Q000008:administration & dosage / Q000494:pharmacology*
D010446:Peptide Fragments; D011963:Receptors, GABA-A; C011393:ACTH (1-10); D001615:beta-Endorphin; D005445:Flunitrazepam; D000324:Adrenocorticotropic Hormone