Methyl parathion induced alterations in monoaminergic system of developing rat pups.

Methyl parathion induced alterations in the level of monoamines, viz. norepinephrine, dopamine and serotonin were studied in discrete regions of developing central nervous system of rat pups. A significant decrease in the level of monoamines noticed in methyl parathion toxicosis may be related to the altered neuronal activity and inefficiency, leading to depression and impairment in various behavioural activities. In contrast to AChE inhibition, monoamine oxidase (MAO) activity showed an increasing trend and it could cause deamination of catecholamines and accumulation of its metabolites. This suggests that an increased AChE inhibition may indirectly stimulate MAO activity in developing rat pups exposed to methyl parathion.

Methyl parathion induced alterations in GABAergic system during critical stage of central nervous system development in albino rat pups.

Sublethal doses of methyl parathion (o, o-dimethyl-o-nitrophenyl thiophosphate) injected intraperitoneally to 7th day old developing albino rat pups induced alterations in the inhibitory GABAergic system of CNS. A substantial simulation of the inhibitory system was noticed. A profound increase was found in the level of the inhibitory transmitter, GABA on methyl parathion injection. An increase in the activity levels of the enzymes glutamic acid decarboxylase and 4-aminobutyrate-2-oxoglutarate-amino transferase in the cortex, brain stem and spinal cord of the CNS was found. It is observed that methyl parathion causes potentiation of the inhibitory transmission (GABAergic system) in the wake of inducing suppression of cholinergic system in CNS of developing rat pups.