and

Aluminium can produce

biphasic

effect.

An

increase

decrease observed of any biological response with increase in

concentration

of

a

test

compound

may

be

termed

as

biphasic

effect.

biphasic

In vitroaluminium

has

been

reported

to

produce

a

effect

on

acetylcholinesterase

(AChE)

activity

[7,15,22]. AChE is a marker enzyme of the cholinergic activity

[12]. Experimental evidence for the biphasic effect of aluminium

observed

explores

in vitro,

are

lacking

in vivo.

aluminium

The

present

study

AChE

the

biphasic

effect

of

in vivoon

activity and the possible mechanism of cause.

MATERIALS AND METHODS

General procedure

200 ± 5 gms were kept on normal diet and tap water ad libitum,

in the animal house with a 12-hour daylight cycle. Aluminium

chloride at a dose of 320 mg/kg body weight was administered

orally for 4, 14 and 60 days. The animals were dosed between

9.30 and 10.30 hrs to avoid time to day variations. The control

group received water orally.