Effects of membrane peroxidation on [3H]acetylcholine release in rat cerebral cortical synaptosomes.
[3H]Acetylcholine (ACh) release, malonaldehyde formation and 45calcium-uptake were measured in rat cerebral cortical nerve terminal that were exposed to various concentrations of ferrous and ascorbate ions. At a constant molar ratio of 25:1, ferrous:ascorbate, these ions increased malonaldehyde (MA) synthesis in a concentration-dependent manner. Treatment with these ions in the same ratio also induced a dose-related inhibition of the K(+)-depolarization-induced release of newly synthesized [3H]ACh. Combined exposure to Fe2+/ascorbate also reduced calcium ionophore A23187-induced [3H]ACh release. Neither ferrous nor ascorbate ions alone altered depolarization- or ionophore-induced [3H]ACh release over this concentration range. Depolarization- and A23187-induced 45calcium uptake were not affected by peroxidation, suggesting that membrane peroxidation influenced some process in the release-process subsequent to calcium influx in a manner similar to what is observed during aging.
Meyer
E M
EM
Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville 32610-0267.
Judkins
J H
JH
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D005296:Ferrous Compounds / Q000494:pharmacology; D015227:Lipid Peroxidation; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D005296:Ferrous Compounds; D008563:Membrane Lipids; D000001:Calcimycin; D008315:Malondialdehyde; D000109:Acetylcholine; D001205:Ascorbic Acid; D011188:Potassium; D002118:Calcium