KUMAR8

In

the

present

study

it

was

observed

that

AChE

activity

in

hippocampus and mid brain regions were not significantly different from

control

level.

Earlier

reports

have

shown

that

hippocampus

was

a

susceptible

region

in

AD

(Edwardson

et

al.,

1992)

and

significant

correlation exists between hippocampal tangle

formation

and

change

in

AChE activity (Perry and Perry, 1980). The observed insignificant change

in AChE activity suggest that the animal was able to overcome aluminium

induced decrease in AChE activity in these two regions. In rats exposed

to

100

µM

aluminium

chloride

for

one

year

in

drinking

water,

while

aluminium level in the brain was reported to be increased, no change in

AChE activity has been reported (Cho and Joshi, 1988). Therefore chronic

exposure

activity.

to

aluminium

may

not

result

in

significant

changes

in

AChE

Aluminium slowly accumulates in the brain and cannot be

removed

(Ganrot,

1986).

Aluminium

induced

neurofibrillary

degeneration

in

susceptible

neuronal

populations

of

rabbits

are

been

the

same

as

those

affected in AD (Meiri et al.,1993). It has

suggested

that

the

presence of aluminium and increased number of lysosomes in hippocampal

neurons of aluminium treated animals induced autolysis of neurons (Galle

et al.,1980).

Though

aluminium

exposure

has

been

shown

to

produce

neurofibrillary degeneration and loss of neurons, in the present study

chronic aluminium exposure had no significant impact on the AChE activity

in hippocampus and mid brain regions.