Effect of ethanol, propanol, butanol, and catalase enzyme blockers on beta-endorphin secretion from primary cultures of hypothalamic neurons: evidence for a mediatory role of acetaldehyde in ethanol stimulation of beta-endorphin release.
Previously, we have shown that low doses of ethanol (12.5-100 mM) and acetaldehyde (12.5-50 microM), but not salsolinol, enhanced immunoreactive beta-endorphin (IR-beta-EP) secretion from fetal hypothalamic neurons in primary culture. In this study, the effects of ethanol, propanol, and butanol, as well as the effect of catalase inhibitors on IR-beta-EP secretion were studied in vitro to determine the role of membrane fluidization and ethanol metabolism on ethanol-induced IR-beta-EP secretion. The primary cultures of fetal hypothalamic neurons were maintained for 8-9 days in chemically defined medium and treated for 5 hr with ethanol (50 mM), propanol (25 and 50 mM), and butanol (25 and 50 mM). Determination of hourly secretion of IR-beta-EP from the cultures revealed that only 50 mM ethanol caused stimulation of IR-beta-EP secretion, whereas propanol and butanol did not alter IR-beta-EP response at any given concentration. Pretreatment of these cultures with the catalase inhibitors, 3-amino-1,2,4-triazole (3-AT; 1, 5, and 10 mM), caused a dose-dependent inhibition of ethanol-stimulated IR-beta-EP secretion, but did not inhibit dibutyryl cAMP (dcAMP)-stimulated IR-beta-EP secretion. Another catalase inhibitor, sodium azide (5 mM), also inhibited ethanol-stimulated IR-beta-EP secretion. Measurement of acetaldehyde production in cultured cells and media after ethanol or dcAMP treatments revealed that cultured cells produce acetaldehyde only after ethanol treatment and at levels of acetaldehyde (8-24 microM) that are known to evoke IR-beta-EP release. The catalase inhibitor 3-AT (10 mM) treatment reduced ethanol-evoked acetaldehyde production.(ABSTRACT TRUNCATED AT 250 WORDS)
Reddy
B V
BV
Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman 99164-6520, USA.
Boyadjieva
N
N
Sarkar
D K
DK
D020001:1-Butanol; D000433:1-Propanol / Q000494:pharmacology*; D000079:Acetaldehyde / Q000378:metabolism / Q000494:pharmacology*; D000640:Amitrole / Q000494:pharmacology; D000818:Animals; D001386:Azides / Q000494:pharmacology; D000440:Butanols / Q000494:pharmacology*; D002374:Catalase / Q000037:antagonists & inhibitors*; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D005333:Fetus; D007031:Hypothalamus / Q000187:drug effects*; D008560:Membrane Fluidity / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D019810:Sodium Azide; D001615:beta-Endorphin / Q000378:metabolism*
D001386:Azides; D000440:Butanols; D000431:Ethanol; D001615:beta-Endorphin; D020001:1-Butanol; D019810:Sodium Azide; D000433:1-Propanol; D002374:Catalase; D000079:Acetaldehyde; D000640:Amitrole