cholinergic

(12), reports on the biphasic effect of

system are scant.

Aluminium and the cholinergic system

aluminium

on

the

Aluminium accumulates in patients suffering from degenerative

diseases

like Alzheimer's disease (7). Severe disturbances in cholinergic function

in

Alzheimer's

disease

was

found

by

Davies

and

Maloney

(8).

The

the

the

cholinergic

deficiency

was

characterized

by

reduced

synthesis

reduction

of

in

enzyme

choline

acetyltransferase

with

a

concomitant

concentration of acetylcholinesterase (AChE). AChE is marker enzyme for

cholinergic

activity

and

hydrolyses

the

excitatory

neurotransmitter

acetylcholine across cholinergic synapses (20). Aluminium administered to

experimental

animals

induced

changes

in

the

cholinergic

system

characteristic of Alzheimer's disease and also reduced the AChE activity

(33).

Biphasic effect due to aluminium exposure on cholinergic system

Aluminium is capable of inducing biochemical changes

in

the

brain

at

shorter

duration

of

exposure.

Gulya

et

al

(12)

have

reported

that

aluminium in vitroproduced a significant increase in AChE activity. In

vivoaluminium increased AChE activity after 5 days of exposure in rat

brain, but the increase was not statistically significant. Patocka (26)

and Marquis and Black (17) have shown that in vitroaluminium caused an

increase in AChE activity at low concentration. Clayton et al (6) have