ABSTRACT
Organophosphate (OP) pesticides, monocrotophos (MCP), dichlorvos (DDVP) and phosphamidon significantly inhibit both MAO-A and MAO-B activities in rat brain mitochondria. The inhibition of MAO-A by MCP is reversible whereas the inhibition by DDVP and phosphamidon is irreversible. MAO-B is inhibited irreversibly by all these organophosphates suggesting that the mechanism of action of OP pesticides is through phosphorylation of serine residue present in active centre of MAO.
Subject(s)
Animals , Benzylamines/metabolism , Brain/enzymology , Insecticides/metabolism , Male , Mitochondria/enzymology , Monoamine Oxidase/metabolism , Organophosphorus Compounds , Oxidation-Reduction , Rats , Rats, Wistar , Serotonin/metabolismABSTRACT
Chlorpromazine, imipramine and amphetamine at a concentration of 0.66, 1.33 and 13.3 x 10(4) M in vitro inhibited acetyl cholinesterase activity by 16, 23 and 31% respectively in rat brain mitochondria. No change in enzyme activity was induced by these drugs in vivo. There is little cholinergic facilitation through acetylcholinesterase inhibition in the presence of psychoactive drugs.
Subject(s)
Acetylcholinesterase/metabolism , Amphetamine/pharmacology , Animals , Brain/enzymology , Chlorpromazine/pharmacology , Cholinesterase Inhibitors/pharmacology , Imipramine/pharmacology , Lithium Chloride/pharmacology , Male , Mitochondria/drug effects , Parasympatholytics/pharmacology , Psychotropic Drugs/pharmacology , Rats , Rats, Inbred StrainsABSTRACT
The psychoactive drugs imipramine, chlorpromazine and lithium chloride inhibit tryptamine tetrazolium reductase activity in vitro by 68, 60 and 33% respectively at a concentration of 1 x 10(-3) M while amphetamine negligibly inhibits the enzyme activity. No change in enzyme activity is observed in vivo.
Subject(s)
Animals , Brain/drug effects , Chlorides/pharmacology , Chlorpromazine/pharmacology , Dextroamphetamine/pharmacology , Imipramine/pharmacology , Lithium/pharmacology , Lithium Chloride , Male , Oxidoreductases Acting on CH-NH Group Donors/antagonists & inhibitors , Psychotropic Drugs/pharmacology , RatsABSTRACT
Of the organophosphate pesticides studied, dichlorvos inhibited significantly both, phosphate-activated glutaminase and alpha-keto acid-activated glutaminase, while monocorotophos inhibited moderately alpha-keto acid activated glutaminase in rat brain. Phosphamidon inhibited glutamine synthetase activity negligibly.