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,
Vol.
8, No.
5,
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
490
Research
Communications,
Vol.
8, No.
5,
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
Research
Communications,
Vol.
8, No.
5,
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.
pharmacol.
1.
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.:
(19661, Physiol.
Behav. 1, l-10.
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.:
(19721,
Ci&cia
e Cultura
2,
308. Sclafani, A. and Grossman, S.P.: (19691, Physiol. Behav. cc, 533-537. Steel, R.G.D. and Torrie, J.H.: (19601, Hill Book Cmpany, Inc. New York 73-75. Stein, L. and Seifter, J.: (19621, Amer. J. Physiol. 202, 751-756. Teitelbaum, P. and Stellar, E.: (19541, Science. 120, 894-895. Wwer, J.W. and De Groat, J.: (19631, Amer. J. Physiol. 2, 483-487.