الفهرس 
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Abstract
Aldicarb, a synthetic carbamate compound used as an insecticide and herbicide, is also employed as a pharmacological cholinergic agent in therapeutic forms.
Inhibition of the enzyme AfihE is the basis for its use as an insecticide and it resulted in toxicity in a variety of animals including man. AChE is responsible for the metabolism of the neurochemical transmitter acetylcholine.
In this thesis, experiments were carried out in vitro and in vivo to study the effects of aldicarb on the activity of ChE enzyme extracted from whole and five different parts of rat brain, namely: basal ganglia, frontal cortex, medulla oblongata, pons and cerebellum. Kinetic measurements of Michaelis constants (Km), enzyme inhibitor dissociation constants (Kj) as ’ well as the rate of cerbamylation and binding constants for the inhibition of the enzyme obtained from the different parts, were done.
The results indicated that aldicarb which is a carbamate compound, had affected the activities of cholinesterase extracted from whole and five different parts of rat brain in vitro as well as in vivo.
The carbamylation rate (degree of inhibition of AChE by carbamate) and binding constant for inhibition of whole and different parts of brain in vitro, indicated that the carbamylation rate constants of pons, medulla oblongata and cerebellum were higher than those for other parts.
Aldicarb inhibited AChE extracted from the above mentioned parts (cerebellum, pons, medulla oblongata) more rapidly than other parts of the brain. Inhibition of AChE of the different parts of the brain in vitro by aldicarb was of the competitive type, with different enzyme inhibitor dissociation constants (Kj).
In vivo studies showed that injection of a single dose of aldicarb at different time intervals, as well as different doses at constant time, resulted in brain AChE inhibition.
The inhibition was marked in the enzyme obtained from pons, medulla oblongata and cerebellum; the parts responsible for vital centres and balance.
It is noteworthy to mention that the parts of rat brain highly affected by aldicarb in vitro were the same parts highly affected in vivo. from our results we could conclude that the difference in the rate of inhibition from one part to another could be due to:-
1- The presence of AChE in these parts in the forms of isozyme as proved
by the difference in Km values (Michaelis constant).
2- The rate of supply of inhibitor to the enzyme, because blood flow
differs between areas of the brain.
3- The concentration of the enzyme in the different parts of the brain.
4- The content of the grey and white matters in these parts.
The parts which showed highi containing more white matter (pons that the white matter contains IrTore (like carbamates) is lipophilic.
ir inhibition by aldicarb were those
and medulla oblongata). It is known
lipid-mlngrey^riattei^nd^ldicarb