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The effect of d-tubocurarine and strychnine on muscle creatine metabolism
Life Sciences Vol. 3, pp. 323-331, 1984. Pergamon Press, Inc. Printed in t he United States .
THE EFFECT OF D-TUBOCURARINE AND STRYCHNINE ON MUSCLE CREATINE METABOLISM Grace M . Eiert* Department oß Pharmacology, Georgetown University Medical and Dental Schools, Washington, D .C .
(Received 18 March 1964) Introduction
The experiments to be described in this paper represent an attempt to re-evaluate the eßßects oß two important drugs, d-tubocurarine and strychnine, on the level oß certain important metabolites oß striated muscle, namely, creatine and phosphoThis present study was stimulated by the ßact that a
creatine .
new, sensitive, and highly specißic method for creatine analysis has recently been develpped . In view oß the well-known convulsant action oß strychnine, it might be expected that a distinct reduction in phosphocreatine levels would be observed ßollowing injection oß this drug .
This
increased utilisation oß phosphocreatine would result Brom intense muscular activity and, indeed,, some reduction in content of this metabolite has been reported ßollowing strychnine, although earlier work is somewhat equivocal in this respect .l
As ßor d-tubo-
curarine, previous work is also contradictory, one investigator reporting an increase in phosphocreatine, 2 still others, essentially no change .3
Most oß this early work was hampered by the ßact that
the drug used was the crude curare alkaloid and the extent oß paralysis, iß any, is not entirely certain .
In view oß current
~n partial ßulßillment oß requirements for the degree oß Master oß Science, Pharmacology Department, Georgetown University Medical and Dental Schools .
323
824
EFFECT OF D-TUBOCURARIIIE AND STRYCHNII~E
~Tol . 3, No . 4
thoughts concerning the trophic effects oß nerves upon voluntary muecle, 4 it seemed of considerable interest to determine in a precise manner whether the interruption of nerve-muscle impulse transmission for even a short period oß time would markedly alter metabolic activity oß muscle as reflected in a change in the phosphocreatine and~or creative levels . Materials and Methods The analytical procedure for creative and phosphocreatine was that described by Ennor and Stockens and Ennor and Rosenburg . s here .
A few modifications were made and these are mentioned
MoIlvaine's phosphate buffer? 0 .2M pH7 was used in place
oß water at pH7 .
One cc oß buffer was added to the 1 ce of the
neutralized Potter-Elvehelm prepared extract when it was being analyzed for free oreatine, and 2 ec oß the buffer was added to 1 cc of the extract when total creative content was determined . In place of using p-merouribenzoate as a sulfhydryl inhibitor, the sodium salt of triiodoacetic aoid (Eastman Organic Chemicals) was used in 0 .5M solution .
p( -naphthol was recrystallized once in
water starting with technical grade material ; white crystals were thus obtained and made up in alkaline solution just prior to use . The oolor reaction was allowed to develop for 20 minutes and peroent transmission determined in a Coleman IIniversal Spectrophotometer, Model 11 at 540 nu, the wavelength of maximum abeorbance . analyses were performed at rooms temperature, 22 to 23° C .
Creative
hydrate was purchased from California Biochemical Co . ; phosphocreatine, from Sigma Chesical Co .
Standard curves for each of
these preparations were determined as well as for mixtures in varying proportions .
d-tubocurarine chloride (Squibb, for
injection, 15 mg~ml) was diluted just before use to 1 mg/nl in distilled water .
All
The crystalline stryohnine sulfate (Fisher
Yol. 3, No . 4
EFFECT OF D-TUHOCURARII~TE AND STRYCHNII~iE
325
Scientific Co .) was made up ßresh in distilled water at a concentration oß 16 to 32 mg/ml . The standard ourves obtained ßor both free creatine and total creatine, straight lines .
i .e ., creatine plus phosphocreatine were
Phosphocreatine content was calculated by sub
tracting the free oreatine from total oreatine .
When running
the standard curve ßor total oreatine, mixtures of oreatine and phoaphocreatine were prepared in varying proportion to eaoh other. Barker and ÉnnorB reported eaoellent recoveries from tissues using this method oß analysis . Injection of animals and eatraotion oß creatine . groups of rata were used . no drug ;
These were :
Three
(a) Eight controls given
(b) Eight curarized rate plus an additional control, and
(o) Eleven rate given strychnine plus an additional control .
The
additional control was used in order to verißy that any d~ißßerences between control values and those obtained ßollowing drug treatment were not due to unaccountable variations in procedures . rapidly killed by immersion in liquid nitrogen .
Rate were
Each oß the con-
trols twitched once or twice while being immersed in the nitrogen . To the second group mentioned, 1 mg/kg oß d-tubocurarine chloride was administered intraperitoneally ; 3 minutes was allowed for the drug to take eßßect, i .e ., ßor complete paralysis to set in . rat was killed one minute after the drug had taken eßfect .
The To the
third group oß rate, strychnine sulfate was given intraperitoneally . Three of the 11 rats were given 2 injections oß 16 mg/kg two to three minutes apart .
The remaining 8 rats were given a single
injection oß 32 mg/kg strychnine sulfate .
About one minute after
injection, the rats became tetanic and remained this way during the entire time allowed ßor.the drug to act ; namely, three minutes .
328
EFFECT OF D-TUHOCURARIIdE AND STRYCHNII~TE
Vol. 3, No . 4
The animals were kept in the liquid nitrogen until oompletely frozen .
A piece of thigh musole, 200-800 mg/rat,
was cleared of adhering skin and connective tissue,~eighed on a torsion balanoe to ± 0 .005 grams, and immediately homogenized without thawing in a Potter type homogenizer in a cold room .
The
homogenate was maintained cold by immersion of the homogenizer tube in an ioe-salt bath .
Two ml . oß 10~ trichloroaoetic aoid per
gram oß tissue was used and the tine for homogenizing was ezactly two minutes .
After homogenisation the plunger was washed with
ezaotly 5 times the volume of 596 triohloroacetio acid .
The tube
oß homogenate was left standing in the ioe bath while the other muscle samples were being homogenized .
After the 596 trichloro-
acetic acid wash, all samples were centrißuged ßor 3 minutes at about 3000 rpm in a olinioal oentrif uge in the cold room .
After
oentrißugation the sample tubes were immediately put in the ice bath
and 2 ml aliquots taken .
These aliquots were put in 10 ml .
Ehrlenmeyer flasks oontaining enough 1 .56N NaOH to neutralize the eztraot to a pH not greater than 9 . residue towel .
The tubes containing the
were then thoroughly drained for 3 minutes on a paper The residues were re-eztracted with the 596 triohloroacetio
aoid and treated in the sane way ae described for the first eztraotion .
Analyses were made for ßree oreatine and total oreatine ae
described above, the values for phosphooreatine being obtained by differenoe . Results The phosphocreatine oontan t of ourarized rat eusole is increased three-ßold over that of oontrol eusole .
The tree oreatine
oß curarized rat eusole is 88'~ oß the oontent in oontrol musole (See Table I, Groups A and B) .
Thus, phosphooreatine is oonserved
in ourarized nuscle,and oonoomitaatly the ßree oreatine level is
Vol. 3, No . 4
EFFECT OF D-TUEOCURARII~TE AND STRYCHNII~TE
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328
EFFECT OF D-TUHOCURARII~iE AND BTRYCHhiINE
lowered .
Vol . 3, No. 4
There is no significant dißßerenoe in the total creatine
content oß the oontrol, curarized, or strychninized rat muscle (Table I, Groups A, B, and C) .
However, the phosphocreatine con-
tent oß strychninized rat muscle is significantly lower than that oß control muscle (Table I, Groups A and C) .
An approximately
~ix-fold reduction in phosphocreatine oooure in stryohninized muscle when based on a comparison with the control ; at times the phosphocreatine level was reduced to zero .
Statistical evalua-
tion oß data from Table I is shown in Table II .
TABLE II a) STATISTICAL EVALIIATION ~ I1ATä SHOWN IN TABLE I
Group A No . of rata
Group B
10
F : Meaa ± S .E . T : Mean ~ S .E . PCs Mena * S .E . b)
B
3 " 21 * 0 .136 3 .88 i 0 .154 0 .6T * 0 .066
2 .13 t 0 .162 4 .30 * 0 .185 2 .17 ; 0 .145
COMPARISON HEIW
GROIIPS
F
T
Groupe AB t p
4 .8 ~ 0 .001
1 .T4 0 .1
Groupe BC t p
8 .8 ~ 0 .001
0 .036 0 .9
3 .3 +~
1 .53 0 .2
Groupe AC t p
Desigaatioa of groupe as o~n Table I e'* indicates statistical aignifioaace F - Free creatine T ~ Total creatine PC ~ (T-F) ~ phoephocreatiae
Group C 11 4 .11 t 0 .11x1 1x .22 t 0 .143 0 .11 t 0 .036
PC 9 .3 ~ 0 .001 15 ~ 0 .001 8 .1 e'# 0 .001
Vol . 3, No. 4
EFFECT OF D-TUHOCURARII~TE AND STRYCHNINE
329
Discussion The results oß these experiments reveal that there was essentially little, iß any, change in the level of total creatine, i .e ., ßree plus phosphocreatine, in striated rat muscle whether the animal was given a convulsant, although aublethal dose oß strychnine, or a paralyzing dose oß d-tubocurarine .
On the other
hand, the content of phosphocreatine i~ the same muscle was very dramatioally altered by the administration of these two drugs, and it is these findings which constitute the primary signißicance oY the experiments performed . The marked decrease in phosphocreatine levels in rats following a convulsant dose oß strychnine is completely in accord with predictions based on current theoY~ies oß high energy utilization during muscular activity.
Thus, the extent oß break-
down oß phosphocreatine was at times so intense as to reveal the complete absenoe oß this compound, at least within the limits oß the method employed .
It would be oß considerable interest to
determine whether under similar conditions of intense phosphocreatine breakdown there ocours a similar parallel decrease in ATP levels . This would be important to determine in view of the reports of Daviea et al . (1950) 9 that ßollowing electrical stimulation oß muscle, the breakdown of phosphocreatine is not attended by a concomitant decrease in ATP levels, a finding which has set ofß a lengthy controversy regarding the predominant roles played by these two high energy phosphates in muscular contraction . 10,11,12 Perhaps the most interesting and important oß our Bindings conoerns the marked and extremely rapid rise in phosphocreatine content ßollowing a paralysing dose oß d-tubocurarine .
This result
strongly supports the idea that the nerve does indeed exert a positive trophic efßect on striated ausole¢
and that the main-
330
EFFECT OF D-TUHOCURARINE AND STRYCHNINE
Vol. 3, No. 4
tenants of normal tone, which evidently is strongly inßluenced by continuous nerve impulses, requires the ezpenditure oß considerable energy .
Other evidence for the strong inßluence of
nerve on voluntary muscle stems ßrom the many observations on the eßfeots oß denervation on musole ßunotion and susoeptibility to drugs ; but these eßßects require very long periods oß time unlike curarization which apparently can affect energy metabolism in a matter oß minutes .
It is Belt that this type of study on
curarized muscle should be eztended to other metabolites in order to gain additional insight into the meohanisms underlying the inßluences on nerve activity on muscle metabolism and function . Acknowledgments The author grateßully acknowledges the quidance and advice of Dr . S . Ehrenpreis in oarrying out this work . This work was supported in part by a grant from the Schering Corp . and ßrom the United States Public Health Service . S ummary l.
Following the intraperitoneal injection oß
d-tubocurarine and strychnine, levels of free creative, phosphocreatine, and total creative were determined in the thigh muscle oß rate by a modißied procedure oß Ennor and Stooken . 2.
The level of phosphocreatine significantly increased
up to 3-ßold in the muscle of the curarized rat when compared to the control . to about 16 .4
In rate injeoted with strychnine the value decreased oß the control value .
There was no signißioant
dißßerenoe in levels oß total creative between control, curarized, and strychninized rat muscle .
The free oreatine level oß the
ourarized rat muscle fell eignißioantly below the value of the control while the free creative level oß strychninized musole rose eignißicantly .
Vol . 3, No . 4 3.
EFFECT OF D-TU~OCURARIIJE AND BTRYCHNII~TE
331
In view oß the great rapidity with which the curare
eßßeot took plane, it is suggested that even brieß blockade of nerve transmission can have a profound eßßect on muscle metabolism . Reßerences 1.
Nachmansohn, D ., Biochem . ztschr ., 213 :262-300 (1929) .
2.
Martino, G ., Boll . Soc . ital . Biol ., 3 :114-116 (1928) .
3.
Lippmann, R . and Wajzer, J ., Compt . rend . Soc . de biol ., 127 :508-510 x1938) .
4.
McIntyre, A . R ., Curare : Its Hietor Nature and Clinical Use, The IIniversity oß Chicago Press, cago 7 ; esleßß, Stephen, Physiological Reviews , 40 :4, 734-750 1960 .
5.
Ennor, A . H ., and Stocken, L . A ., Biochem . J .
6.
Ennor, A . H., and Rosenburg, H ., Biochem . J ., 51 :606 (1952) .
7.
Lange, N . A ., Handbook _of Chemistry , Handbook Publishers, Inc, Sandusky, Ohio 1952 .
8.
Barker H., and Ennor, A . H ., Biochem . et Biophysics Acta , 7 :272 x1951) .
9.
Davier, R . E ., Cain, D ., Delluva, A . M ., Annals _oß _the _New York Aoad . oß Sciences , 81 : art . 2, 2699 1959 .
42 :557 (1948) .
10 .
Mommaerts, W. F . H . M ., Nature , London, 168 :957 (1951) .
11 .
Munoh-Peterson, A ., Acta Physiol . Scand ., 29 :202-219 (1953) .
12 .
Mom®sorts, W . F . H . M ., Nature , London, 174 :1083 (1954) .
THE EFFECT OF D-TUBOCURARINE AND STRYCHNINE ON MUSCLE CREATINE METABOLISM Grace M . Eiert* Department oß Pharmacology, Georgetown University Medical and Dental Schools, Washington, D .C .
(Received 18 March 1964) Introduction
The experiments to be described in this paper represent an attempt to re-evaluate the eßßects oß two important drugs, d-tubocurarine and strychnine, on the level oß certain important metabolites oß striated muscle, namely, creatine and phosphoThis present study was stimulated by the ßact that a
creatine .
new, sensitive, and highly specißic method for creatine analysis has recently been develpped . In view oß the well-known convulsant action oß strychnine, it might be expected that a distinct reduction in phosphocreatine levels would be observed ßollowing injection oß this drug .
This
increased utilisation oß phosphocreatine would result Brom intense muscular activity and, indeed,, some reduction in content of this metabolite has been reported ßollowing strychnine, although earlier work is somewhat equivocal in this respect .l
As ßor d-tubo-
curarine, previous work is also contradictory, one investigator reporting an increase in phosphocreatine, 2 still others, essentially no change .3
Most oß this early work was hampered by the ßact that
the drug used was the crude curare alkaloid and the extent oß paralysis, iß any, is not entirely certain .
In view oß current
~n partial ßulßillment oß requirements for the degree oß Master oß Science, Pharmacology Department, Georgetown University Medical and Dental Schools .
323
824
EFFECT OF D-TUBOCURARIIIE AND STRYCHNII~E
~Tol . 3, No . 4
thoughts concerning the trophic effects oß nerves upon voluntary muecle, 4 it seemed of considerable interest to determine in a precise manner whether the interruption of nerve-muscle impulse transmission for even a short period oß time would markedly alter metabolic activity oß muscle as reflected in a change in the phosphocreatine and~or creative levels . Materials and Methods The analytical procedure for creative and phosphocreatine was that described by Ennor and Stockens and Ennor and Rosenburg . s here .
A few modifications were made and these are mentioned
MoIlvaine's phosphate buffer? 0 .2M pH7 was used in place
oß water at pH7 .
One cc oß buffer was added to the 1 ce of the
neutralized Potter-Elvehelm prepared extract when it was being analyzed for free oreatine, and 2 ec oß the buffer was added to 1 cc of the extract when total creative content was determined . In place of using p-merouribenzoate as a sulfhydryl inhibitor, the sodium salt of triiodoacetic aoid (Eastman Organic Chemicals) was used in 0 .5M solution .
p( -naphthol was recrystallized once in
water starting with technical grade material ; white crystals were thus obtained and made up in alkaline solution just prior to use . The oolor reaction was allowed to develop for 20 minutes and peroent transmission determined in a Coleman IIniversal Spectrophotometer, Model 11 at 540 nu, the wavelength of maximum abeorbance . analyses were performed at rooms temperature, 22 to 23° C .
Creative
hydrate was purchased from California Biochemical Co . ; phosphocreatine, from Sigma Chesical Co .
Standard curves for each of
these preparations were determined as well as for mixtures in varying proportions .
d-tubocurarine chloride (Squibb, for
injection, 15 mg~ml) was diluted just before use to 1 mg/nl in distilled water .
All
The crystalline stryohnine sulfate (Fisher
Yol. 3, No . 4
EFFECT OF D-TUHOCURARII~TE AND STRYCHNII~iE
325
Scientific Co .) was made up ßresh in distilled water at a concentration oß 16 to 32 mg/ml . The standard ourves obtained ßor both free creatine and total creatine, straight lines .
i .e ., creatine plus phosphocreatine were
Phosphocreatine content was calculated by sub
tracting the free oreatine from total oreatine .
When running
the standard curve ßor total oreatine, mixtures of oreatine and phoaphocreatine were prepared in varying proportion to eaoh other. Barker and ÉnnorB reported eaoellent recoveries from tissues using this method oß analysis . Injection of animals and eatraotion oß creatine . groups of rata were used . no drug ;
These were :
Three
(a) Eight controls given
(b) Eight curarized rate plus an additional control, and
(o) Eleven rate given strychnine plus an additional control .
The
additional control was used in order to verißy that any d~ißßerences between control values and those obtained ßollowing drug treatment were not due to unaccountable variations in procedures . rapidly killed by immersion in liquid nitrogen .
Rate were
Each oß the con-
trols twitched once or twice while being immersed in the nitrogen . To the second group mentioned, 1 mg/kg oß d-tubocurarine chloride was administered intraperitoneally ; 3 minutes was allowed for the drug to take eßßect, i .e ., ßor complete paralysis to set in . rat was killed one minute after the drug had taken eßfect .
The To the
third group oß rate, strychnine sulfate was given intraperitoneally . Three of the 11 rats were given 2 injections oß 16 mg/kg two to three minutes apart .
The remaining 8 rats were given a single
injection oß 32 mg/kg strychnine sulfate .
About one minute after
injection, the rats became tetanic and remained this way during the entire time allowed ßor.the drug to act ; namely, three minutes .
328
EFFECT OF D-TUHOCURARIIdE AND STRYCHNII~TE
Vol. 3, No . 4
The animals were kept in the liquid nitrogen until oompletely frozen .
A piece of thigh musole, 200-800 mg/rat,
was cleared of adhering skin and connective tissue,~eighed on a torsion balanoe to ± 0 .005 grams, and immediately homogenized without thawing in a Potter type homogenizer in a cold room .
The
homogenate was maintained cold by immersion of the homogenizer tube in an ioe-salt bath .
Two ml . oß 10~ trichloroaoetic aoid per
gram oß tissue was used and the tine for homogenizing was ezactly two minutes .
After homogenisation the plunger was washed with
ezaotly 5 times the volume of 596 triohloroacetio acid .
The tube
oß homogenate was left standing in the ioe bath while the other muscle samples were being homogenized .
After the 596 trichloro-
acetic acid wash, all samples were centrißuged ßor 3 minutes at about 3000 rpm in a olinioal oentrif uge in the cold room .
After
oentrißugation the sample tubes were immediately put in the ice bath
and 2 ml aliquots taken .
These aliquots were put in 10 ml .
Ehrlenmeyer flasks oontaining enough 1 .56N NaOH to neutralize the eztraot to a pH not greater than 9 . residue towel .
The tubes containing the
were then thoroughly drained for 3 minutes on a paper The residues were re-eztracted with the 596 triohloroacetio
aoid and treated in the sane way ae described for the first eztraotion .
Analyses were made for ßree oreatine and total oreatine ae
described above, the values for phosphooreatine being obtained by differenoe . Results The phosphocreatine oontan t of ourarized rat eusole is increased three-ßold over that of oontrol eusole .
The tree oreatine
oß curarized rat eusole is 88'~ oß the oontent in oontrol musole (See Table I, Groups A and B) .
Thus, phosphooreatine is oonserved
in ourarized nuscle,and oonoomitaatly the ßree oreatine level is
Vol. 3, No . 4
EFFECT OF D-TUEOCURARII~TE AND STRYCHNII~TE
ONSOÔ .OO~~NN~
OOOOOOOOOOOIIO
b
O
~R~R~v`~o,N~$ t111~ .~ -~ M M ~ -a ~ -~ -~
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p
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ri
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327
328
EFFECT OF D-TUHOCURARII~iE AND BTRYCHhiINE
lowered .
Vol . 3, No. 4
There is no significant dißßerenoe in the total creatine
content oß the oontrol, curarized, or strychninized rat muscle (Table I, Groups A, B, and C) .
However, the phosphocreatine con-
tent oß strychninized rat muscle is significantly lower than that oß control muscle (Table I, Groups A and C) .
An approximately
~ix-fold reduction in phosphocreatine oooure in stryohninized muscle when based on a comparison with the control ; at times the phosphocreatine level was reduced to zero .
Statistical evalua-
tion oß data from Table I is shown in Table II .
TABLE II a) STATISTICAL EVALIIATION ~ I1ATä SHOWN IN TABLE I
Group A No . of rata
Group B
10
F : Meaa ± S .E . T : Mean ~ S .E . PCs Mena * S .E . b)
B
3 " 21 * 0 .136 3 .88 i 0 .154 0 .6T * 0 .066
2 .13 t 0 .162 4 .30 * 0 .185 2 .17 ; 0 .145
COMPARISON HEIW
GROIIPS
F
T
Groupe AB t p
4 .8 ~ 0 .001
1 .T4 0 .1
Groupe BC t p
8 .8 ~ 0 .001
0 .036 0 .9
3 .3 +~
1 .53 0 .2
Groupe AC t p
Desigaatioa of groupe as o~n Table I e'* indicates statistical aignifioaace F - Free creatine T ~ Total creatine PC ~ (T-F) ~ phoephocreatiae
Group C 11 4 .11 t 0 .11x1 1x .22 t 0 .143 0 .11 t 0 .036
PC 9 .3 ~ 0 .001 15 ~ 0 .001 8 .1 e'# 0 .001
Vol . 3, No. 4
EFFECT OF D-TUHOCURARII~TE AND STRYCHNINE
329
Discussion The results oß these experiments reveal that there was essentially little, iß any, change in the level of total creatine, i .e ., ßree plus phosphocreatine, in striated rat muscle whether the animal was given a convulsant, although aublethal dose oß strychnine, or a paralyzing dose oß d-tubocurarine .
On the other
hand, the content of phosphocreatine i~ the same muscle was very dramatioally altered by the administration of these two drugs, and it is these findings which constitute the primary signißicance oY the experiments performed . The marked decrease in phosphocreatine levels in rats following a convulsant dose oß strychnine is completely in accord with predictions based on current theoY~ies oß high energy utilization during muscular activity.
Thus, the extent oß break-
down oß phosphocreatine was at times so intense as to reveal the complete absenoe oß this compound, at least within the limits oß the method employed .
It would be oß considerable interest to
determine whether under similar conditions of intense phosphocreatine breakdown there ocours a similar parallel decrease in ATP levels . This would be important to determine in view of the reports of Daviea et al . (1950) 9 that ßollowing electrical stimulation oß muscle, the breakdown of phosphocreatine is not attended by a concomitant decrease in ATP levels, a finding which has set ofß a lengthy controversy regarding the predominant roles played by these two high energy phosphates in muscular contraction . 10,11,12 Perhaps the most interesting and important oß our Bindings conoerns the marked and extremely rapid rise in phosphocreatine content ßollowing a paralysing dose oß d-tubocurarine .
This result
strongly supports the idea that the nerve does indeed exert a positive trophic efßect on striated ausole¢
and that the main-
330
EFFECT OF D-TUHOCURARINE AND STRYCHNINE
Vol. 3, No. 4
tenants of normal tone, which evidently is strongly inßluenced by continuous nerve impulses, requires the ezpenditure oß considerable energy .
Other evidence for the strong inßluence of
nerve on voluntary muscle stems ßrom the many observations on the eßfeots oß denervation on musole ßunotion and susoeptibility to drugs ; but these eßßects require very long periods oß time unlike curarization which apparently can affect energy metabolism in a matter oß minutes .
It is Belt that this type of study on
curarized muscle should be eztended to other metabolites in order to gain additional insight into the meohanisms underlying the inßluences on nerve activity on muscle metabolism and function . Acknowledgments The author grateßully acknowledges the quidance and advice of Dr . S . Ehrenpreis in oarrying out this work . This work was supported in part by a grant from the Schering Corp . and ßrom the United States Public Health Service . S ummary l.
Following the intraperitoneal injection oß
d-tubocurarine and strychnine, levels of free creative, phosphocreatine, and total creative were determined in the thigh muscle oß rate by a modißied procedure oß Ennor and Stooken . 2.
The level of phosphocreatine significantly increased
up to 3-ßold in the muscle of the curarized rat when compared to the control . to about 16 .4
In rate injeoted with strychnine the value decreased oß the control value .
There was no signißioant
dißßerenoe in levels oß total creative between control, curarized, and strychninized rat muscle .
The free oreatine level oß the
ourarized rat muscle fell eignißioantly below the value of the control while the free creative level oß strychninized musole rose eignißicantly .
Vol . 3, No . 4 3.
EFFECT OF D-TU~OCURARIIJE AND BTRYCHNII~TE
331
In view oß the great rapidity with which the curare
eßßeot took plane, it is suggested that even brieß blockade of nerve transmission can have a profound eßßect on muscle metabolism . Reßerences 1.
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