Effect of intrahypothalamic injection of methylic parathion and metasystox on food and water intake of normal and fasted rats

Effect of intrahypothalamic injection of methylic parathion and metasystox on food and water intake of normal and fasted rats

Pharmacological Research Communications, Vol. 8, No. 5, 485 1976 EFFECTOF INTRAHYP3lHALAMICINJECTION OF ME'IHYLIC PARATHIONAND METASYSTOX ON F...

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Pharmacological

Research

Communications,

Vol.

8, No.

5,

485

1976

EFFECTOF INTRAHYP3lHALAMICINJECTION OF ME'IHYLIC PARATHIONAND METASYSTOX ON FOODANDWATERINTAKE OF NORMALANDFASTEDRATS.

W.A. Saad, L.A.A.

Camargo, A.M. Cabral,

N. Morita

LkparGnant of Physiological

and Y. Yashuda.

Sciences

Schml of Pharmacy and Odontology Araraquara. S.P. Brasil C&go n? 14.800 Received

7 January

1976

SUMMARY. Methylic

parathion

(O,O-dimethyl-0-p-nitrophenyl

mtasystox

(O,O-dimethyl-0-ethyl-mercaptophenyl

jected

into

the lateral

cleus

(V.M.N.)

the quantities

hypothalamic

through

permanently

into

in focd intake;

jected

in the V.M.N.; mreover,

opposite

INTRODUCTION. Previms

ms,

plays a role mall

lesions

causes water intake injected

implanted

into this

effects

in the regulation in this (Miller,

The injection

increase

medial nuin

of these or-

in water intake

were also quantitatively

have shown that of water intake

area prcduce adipsia, 1960; Teitelbaum

area also stirmlates

and the ventral

in-

and a de-

were observed when the drugs were in-

the effects

investigations

directly

and

cannulae caused alterations

by rats.

the L.H.A. caused an

crwse

phosphothioate) (L.H.A.)

of food and water ingested

ganophosphorates

lams,

area

phosphothioate)

the

hypotha-

as well as food intake.

while

and Stellar,

water intake

lateral

different.

electric 1954).

sttiation Carbachol

(Grossman, 1960; Grossman

Pharmacological

486

Research

Colrlrrlllnicatlorls,

Vol.

1960a; Grossman, 1962b; Antunes-Rcdrigues

and Covian, 1971).

have shown the existence

between

appetitive

behavior

mssman,

of a correlation

(Albert

and Storlien,

1969;

Other and

Gold,

5, 1976

studies

L.1I.A. in this

1970b;

Sclafani

and

1969).

Recently,

the studies

of Oliveira

using anticholinesterasic between L.H.A. In this

et al.

(1972) and Camargo et al.

have shown a cholinergic

drugs,

and V.M.N. in the water and food intake study,

structurally

we compared

different

effects

interrelationship

regulation.

reinforce

drugs,

(Camargo et al.,

agents were directly

obtained

(1975)

of anticholinesterasic

previously

The cholinergic

L.H.A. and V.M.N.. The results margo et al.,

the

from those used

water and food intake.

1975)

injected

our previous

on

into the

conclusions

(Ca-

1975).

MATERIALSA.NDMEXHOlX. Holtzman male rats, were used in our experiments. cages supplied tion.

'J.M.N.

S, No.

weighing

between 250 and 280 g,

The animals were put into individual

with two devices for the measuring

of

metabolic

water and food consump-

The rats were fed ad libitum. Stainless

planted

in the

steel

cannulae,

V.M.N.,

or

in the L.H.A.,

(1959) *

After

submitted

to the experimental

take for periods received

a seven day period,

of 1,

stereotaxically

using the coordinates

as follows:

24 hours were studied

injection

In a second experiment,

were

im-

of De Groat

the animals were considered prepared to be

conditions,

6 and

an intrahypothalamic

or L.H.A.).

0.5 mm in diameter,

the water and food inin the animals which had

of the anticholinesterasic

drug (V.M.N.

the same animals were deprived

of food and

water for 24 hours,

after

(V.M.N. or L.H.A.).

The water and food consumption were then recorded for pe-

riods

which they received

the intrahypothalamic

injection

of 1, 6 and 24 hours. The drugs were dissolved

in a volun-e of 1 and 2 ~1.

in inert

oil

In the control

and injected experiments

intrahypothalamically the animals received

an

Pharmacological

Research

Communicatior,s,

equal volume of inert parathion

oil

Vol.

8, No.

5,

487

1976

1 and 2 ~1 of the stock solution

alone.

and metasystox were injected

milton

- U.S.A.)

tubing

PE 10 of 20 cm, which permitted

of mathylic

by means of a 10 ~1 microsyringe

connected to an injecting

(Ha-

cannulae by a piece of polyethilene the injection

in approximately

20 sec-

onds. solutions

stock phosphothioate) thioate)

of

methylic

and metasystox

parathion

(O,O-dimethyl-0-ethyl-mercaptophenyl

in a 99% v/v concentration,

At the end of the experiments, brains

removed. The brains

after

which they were tirsed

tine.

Ten microns sections

Weigert (modification experiments

(O,O-dimethyl-0-p-nitrophenyl

were obtained

from Bayer AG - G.F.R..

the

were

animals

sacrificed

were kept in a 10% formaldehyde in paraffine were used,

of Ehrart,

and submitted

stained

by

1951) techniques.

The results

and-their

solution

for a week,

to hystological

the

galocyanine

rou-

and Pal-

The data ccanputed in these

are those from the animals whose cannulations

M.N. were performed

phospho-

in the

L.H.A.

or V.

correctly.

were presented

For data cunparison,

as the mean 2 S.E.M.

the

t

test

of Student was used (Steel

and Torrie,

1960).

RESULTS.

Effects

of methylic

M.N. on water intake the application

in fed and starved

of 2 ~1 of methylic

observed in the fed animals. 6th and 24th hour after mals submitted crease inwater

after

ter intake

rats

Water intake

to 24 hours fast,

at the first

(figs.

the

difference of the drug.

increased

effect hour,

into

the L.H.A.

1 and 2).

an increase

of both,

intake only in the first

the injection

injection

parathion,

the application

marks there was no significant periods

and metasystox

and V.

One hour after

of water intake was

in this

same group in the

1 and 2 ~1 doses. In the ani-

of methylic while

parathion

for

all

between the control l+tasystOx

was an in-

the other time periods and the

caused an increase

and 6th hour time marks when applied

into

in wa-

the L.H.A.

Pharmacological

488

of fed rats

Communications,

in 1 and 2 ~1 doses and at the 24th hour

doses. In starved rats, when injected

Research

into

Vol.

8, No,

mark when applied

the same drug also caused an increase

in 2 )11

in the first

the L.H.A. in 1 and 2 ~1 doses. This increase

the 24th hour mark mainly with the 1 ~1 dose. 'Ihe application

5, 7976

hour

was evident

at

of rrrathylic para-

FASTED 19’

SAMPLING

TIME

MUf?S~

Fig. 1 - Influence of the injection of mthylic the lateral hypothalamic area (L.H.A.) arKI fasted rats.

parathion and metasystox into on the water intake of satiated

0, PC 0,05; ooo, P c 0,001. Figures within parenthesis represent the number of experiments. Vertical bars represent the Standard error of the mean. thion

to the V.M.N. of fed rats

of the experimsntaltimmarks. 6th

and

24th

did not

after

the level

In starved animals,

it

of water intake

at any

caused a decrease at the

hour time mark with the 2 ~1 dose.

As to the V.M.N.,

rnetasystox

mals at the 24th hour time mark.

caused a water intake In starved

animals,

inhibitim

in fed ani-

mstasystox

caused a de-

Pharmacological

Research

Communications,

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489

1976

V MN.

SATIATED

FASTED

SAMPLING TM Fig.

2 - Influence of the injection the ventral medial nucleus

MWRS~

of methylic

parathion

and metasystox

(V.M.N.) of the hypothalams intake of satiated and fasted rats. 0, P-z 0,05; cm, P c 0,001. Figures within parenthesis number of experiments.

Vertical

bars represent

into

on the water represent

the standard

the

emorof

the m-an. crease in water intake

when injected

into the V.M.N. in the 1~1 dose at the 24

hourstimmk. Effects

of the injection

and V.M.N.

of m?thylic

on the food intake

crease of food intake thylic

parathion

&S,

a decrease

with

2 ~1 of methylic

was observed in fed rats

in the L.H.A. of

and metasystox

of fed and starved rats after

(figs. a

into

the

3 and 4).

2 ~1 injection

at the 6th and 24th hour marks.

In starved

L.H.A. A deof maani-

food intake was observed only at the 24 hours time mark parathion

injected

systox caused a drop in fcod intake the L.H.A.

parathion

into the L.H.A..

at the 6 hours tim

In fed animals, mark when injected

in a 2 P dose, and at the 24 hours mark when injected

metainto

in 1 and 2 ~1

Pharmacological

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7976

L. H. A.

25-

20-

15-

SATIATED

IO-

5-

SAMPLING TM Fig.

3 -

Influence of the injection of methylic the lateral hypothalamic area (L.H.A.) o, PC 0,05; 00, PC 0,Ol; represent ard error

doses.

the effect

in food intake

doses.

As to the V.M.N.,

creased

in food intake

with the 1 ~1 dose.

Vertical

atallexperimentdl

methylic

an increase

of mtasystox 24

the stand-

into the L.H.A.

marks andwith

the two

parathion

caused an in-

the land

2 p doses. In

into the V.M.N. caused an increase

hours time markswithbothdoses. in food intake

into

parenthesis

bars represent

tim?

at the 6 hours timemarkwith

at the 6 and

ani.mals,therewa~

Figures within

of nretasystox injected

in fed animals,

the fed animals the injection intake

parathion ark3 metasystox on the ingestion of food.

000, P 40,001.

the number of experiments. of the mean.

In sta??ved animals,

was adecrease

in food

(l-OURS)

attheland

24

In

starved

hourstimemarks

Pharmacological

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Communications,

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SATIATED

I

1976

FASTED

; Fj

6

SAMPLING

TIME

OmJRs~

of methylic parathion and mtasystox into Fig. 4 - Influence of the injection the ventral medial nucleus (V.M.N.) of the hypothalams on the ingestion of food. o, PC 0,OS; 00, PC 0,Ol; 000, PC 0,001. Figures within parenthesis represent the standrepresentthenunker of experiments. Verticalbars ardermrofthemean. DISCLRSION. The application producedamp reversible mscarinic, tylcholine

roeminent

but not nicotinic (Stein

of Miller

genous excretion

stimlation 1962).

showed that stimulation

(1965).

that

drugs

produced by the

This effect

was due to

of endogenous ace-

As far as the V.M.N. is ccmcemed these

(1964) who used cholinergic

effect

than

of the liberation

of water intake,

of acetylcholine.

anticholinesterasic

on water intake

used by Miller

and Seifter,

the L.H.A. and an inhibitory sults

effect

anticholinesterasic

drugs produced an inhibition findings

of these irreversible

which

is

stimulation

in contrast instead

These data suggest a stimlating of the V.M.N.. As to food intake,

of the V.M.N. produces a "excitatory"

with the of

endo-

effect

of

our

re-

effect

on

492 this

Pharmacological

appetitive

behavior.

ter the sttilation

Research

Communications,

Vol.

Wagner and De Groat (1963) reported The findings

of V.M.N..

the V.M.N., when stimulated

by adrenergic

of Qossman

drugs,

induces water intake;

thus,

ing through

cholinergic

pathways is attributed

to the V.M.N..

lating

effect

versible

on food intake.

ololinergic

anticholinesterasic

comparing the results can say that

while the behavior

with metasystox

vious study (Camargo et al.,

parathion

1975) with ethylic

tation

of this

bility

properties

lipids

and the organophosphorates

longer duration tratim

is that the inhibition

of the inhibitors:

of their

of metasystox

plains

are

actions

the

of

to that

parathion. brain

brain

in the nervous stictures

parathion

we

more marked,

observed in a preinterpre-

a high proportion thus explaining

The attained is,

When

ChEs depends on the solu-

contains

1961).

act-

and a stimu-

A possible

are more lipid-soluble, (Heath,

effect

in water intake.

generally

was similar

while

of the L.H.A. by irre-

and with methylic

produced by metasystox

of n-ethylic

fact

stimulation

af-

Gur experiments

on water intake

agents produced an increase

obtained

the effects

of the V.M.N.

an inhibitory

1976

proved that

provokes foccl intake,

stimulation

function

5,

food intake

(1966a)

cholinergic

also showed an inhibitory

8, No.

therefore

effective

of the,

concen-

greater

which ex-

of endogencus brain acetylcholine

released

the more pronounced effects. We may conclude that

by the application lating

effect

of anticholinesterasic

on water intake

V.M.N. is involved, ous results

the action

opposite

drugs to the L.H.A. produces a stti-

and an inhibitory effects

with suggest the existence

action

are observed.

on food intake.

When the

These data reinforces

of an integrated

cholinergic

circuit

previbe-

tween the V.M.N. and the L.H.A..

This work was supported

by a grant from the F.A.P.E.S.P.

The authors wish to thank Mr R~~-~&code technical

assistence.

As&

Tirade

S&o Paulo-Brasil. for

his excellent

Pharmacological

Research

Communications,

Vol.

8, No.

5,

1976

493

REFERENCES

Albert, D.L. and Storlien, L.H.: (19691, Science. 3, 599-600. Camargo, L.A.A., Yashuda, Y., Saad, W.A. and C&oral, A.M.: (19751, Research Corn. 1, 189-197. De Qxot, J.: (19591, Trans. Royal. Neth. Acad. Sci. 2, Ehrart, E.A.: (19511, Arquiv. Neuro-Psiquiat. 2, 372.

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Gold, R.M.: (1970b), Physiol. Behav. 2, 23-25. cilT3ssman, S.P.: (19601, Science. 132, 301-302. Gpossman, S.P.: (1962a1, Amer. J. Physiol. 202, 872-882. mssman, S.P.: (1962b), Amer. J. Physiol. 202, 1230-1236. Grossman, S.P.:

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Gmssman, S.P., Rodrigues, J.A. and Covian, M.R.: (1971), Fxperientia. 27, 784. Miller, N.E.: (19601, Fed. Proc. l9-, 846-853. Miller, N.E.: (19651, Science. 148, 328-338. Miller, N.E., Cottesmn, K.S. and Rnery, N.: (19641, Amer. J. Physiol. 2, 1384-1388. Oliveira, J.A., Camargo, L.A.A.

and Saad, W.A.:

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