Pharmacology Biochemistry& Behavior, Vol. 9, pp. 469~,72. Printed in the U.S.A.
Effect of Taurine on Some Pharmacological Properties of Ethanol W I L L I A M O. B O G G A N , : : C H U C K M E D B E R R Y , A N D D A V I D H. H O P K I N S
Department o f Psychiatry and Behavioral Sciences and Biochemistry, Medical University o f South Carolina Charleston S C ( R e c e i v e d 2 J u n e 1978) W. O. BOGGAN, C. MEDBERRY AND D. H. HOPKINS. Effect of taurine on some pharmacological properties ql" ethanol. PHARMAC. BIOCHEM. BEHAV. 9(4) 469-472, 1978.--Taurine was effective in reducing the hypnotic effect of ethanol but did not antagonize the effect of ethanol on seizure susceptibility, body temperature, or brain 5-HIAA concentration. Taurine
Pharmacological effects
Ethanol
IT HAS BEEN reported [171 that acute, simultaneous injection of taurine (2-aminoethanesulfonic acid) reduces ethanol induced sleep time of mice. This reduction was substantially greater than that produced by 9 other amino acids which were administered at a similar concentration. Several possible mechanisms may underlie this antagonism. For example, it has been postulated that taurine is a neuromodulator or inhibitory transmitter. In support of these hypotheses are the following: iontophoretically administered taurine causes a depressor effect on most neurons [5, 6, 12, 14]; taurine appears to be concentrated in synaptosomal fractions [7,29] (though it is possible that it occurs within glia cells [91); it can be released by chemical and electrical stimulation [ 18] and be taken up into brain slices [201. Taurine may be a membrane stabilizer on the basis of data from the sacroplasmic reticulum from rat skeletal muscle wherein taurine caused an increase in the rate of calcium oxalate uptake, an increase in the total calcium sequestered, and a decrease in the rate of calcium transport after treatment of the preparation with phospholipase C 116]. An increase in the mitochondrial binding of calcium after taurine has also been reported [81. Furthermore, taurine in the intact dog heart prevents the efflux of potassium which accompanies large doses of epinephrine [25J. Much of this work has been summarized I3,4]. A third possible mechanism for the reduction of ethanol induced sleep time by taurine was suggested by lida and Hikichi [ 171. They speculated that taurine may form a complex with ethanol or acetaldehyde or increase the metabolic rate of ethanol. One purpose of our investigation was to examine the effect of taurine on circulating levels of ethanol. Since taurine did antagonize the effects of ethanol on sleep time 117] we questioned whether taurine would also antagonize some of the other reported effects of ethanol. Specifically, we attempted to replicate the effect of taurine on ethanol induced sleeping time and to study its effects on
ethanol induced decreases in body temperature I 11, 26, 321, seizure susceptibility II, 23, 36], and increase in brain 5-hydroxyindole acetic acid 1311. METHOD Adult male C57BL/6J mice purchased from the Jackson Laboratories (Bar Harbor, Maine) were used in these studies. All animals were housed 5 per cage in a 7:00 p.m.7:00 a.m. dark-light cycle with continuous access to water and Wayne Mouse Breeder Blox. The mice were randomly assigned to the experimental groups and each animal was used only once. In every experiment, each taurine solution was adjusted to pH 7.0 with dilute NaOH.
ltturine and Ethanol Induced Sleeping Time Mice were fasted overnight with continuous access to HeO. At 10 a.m. the next morning they were injected intraperitoneally with ethanol (3.5 g/kg, 0.2 ml/10 g body wt. prepared from 95%. ethanol) or with ethanol plus taurine (45 mg/kg; 0.2 ml/10 g body wt.). Sleeping time was measured as the total elapsed time from the initial loss of righting reflex to the animals" return without remission to all 4 feet. The righting reflex was considered lost if the animal, when placed on its back, did not right itself. The sleep time experiment was conducted in a constant temperature room 25 _+ 0.1°C and was repeated 3 times. The data were analyzed by t-tests.
Taurine attd Ethanol Induced Hypothermia Baseline rectal temperatures of mice were taken by inserting a small animal probe attached to a telethermometer (Yellow Springs Instrument, Model 43TA) approximately 3 cm into the colon. The animals were lightly restrained by the tail during this procedure, lnitial mean rectal temperatures of the groups were determined to be equal prior to the onset of the experiments. The mice were then injected with ethanol (2 g/kg: 0.2 ml/10 g body wt.) or with ethanol plus taurine (30
'This work was supported by a research grant No. AA01865 to William O. Boggan from the National Institute on Alcohol Abuse and Alcoholism. -'Department of Psychiatry and Behavioral Sciences and Biochemistry, Medical University of South Carolina, Charleston. SC.
C o p y r i g h t ' 1978 A N K H O I n t e r n a t i o n a l !nc.--0091-3057/78/100469-04500.80/0
470
B O G G A N E 7 AI,. b e e n p r e v i o u s l y s h o w n to be the optimal time Io see the i n c r e a s e in brain 5 - H I A A after E T O H I311. T h e b r a i n s were a n a l y z e d for 5 - h y d r o x y t r y p t a m i n e {5-HT) a n d 5-H1AA by the m e t h o d o f J o n s s o n and L e w a n d e r 1191. T h e s e data were a n a l y z e d by a n a l y s i s of vltriance a n d t-tests.
mg/kg: 0.2 ml/10 g b o d y wt. : this dose of t a u r i n e w a s c h o s e n for this e x p e r i m e n t b e c a u s e h i g h e r d o s e s were f o u n d to prod u c e h y p o t h e r m i a by t h e m s e l v e s ) . T h e t e m p e r a t u r e was t a k e n again 30, 60, 121) and 240 min after injection. T h e s e studies were carried out in a c o n s t a n t t e m p e r a t u r e room of 25 _, 0. I°C a n d the data were a n a l y z e d by a n a l y s i s of varia n c e on r e p e a t e d m e a s u r e s .
RESUI.IS T a u r i n e significantly r e d u c e d the sleeping time of a n i m a l s receiving e t h a n o l . E t h a n o l ( N - 2 3 ) - 4 7 . 3 +_ 5.5 rain: E t h a n o l plus T a u r i n e I N - 2 3 ) - 2 5 . 9 - + 3.6 min, r ~3.18, p < 0 . 0 0 3 . Data are given as m e a n _+ S.E. A l t h o u g h e t h a n o l a d m i n i s t r a t i o n d e c r e a s e d body temp e r a t u r e as a f u n c t i o n o f time F ( 2 . 2 8 ) - 6 3 . 2 5 . p - : 0 . 0 1 , t a u r i n e did not a n t a g o n i z e t h e s e effects f l ' a b l e I). T a u r i n e also failed to a n t a g o n i z e the effects of e t h a n o l on c l e c t r o c o n vulsive s h o c k {Table 2) and to alter the a m o u n t o f circulating e t h a n o l ~Tablc 1). E t h a n o l p r o d u c e d a significant (p
Effect of Taurine on Some Pharmacological Properties of Ethanol W I L L I A M O. B O G G A N , : : C H U C K M E D B E R R Y , A N D D A V I D H. H O P K I N S
Department o f Psychiatry and Behavioral Sciences and Biochemistry, Medical University o f South Carolina Charleston S C ( R e c e i v e d 2 J u n e 1978) W. O. BOGGAN, C. MEDBERRY AND D. H. HOPKINS. Effect of taurine on some pharmacological properties ql" ethanol. PHARMAC. BIOCHEM. BEHAV. 9(4) 469-472, 1978.--Taurine was effective in reducing the hypnotic effect of ethanol but did not antagonize the effect of ethanol on seizure susceptibility, body temperature, or brain 5-HIAA concentration. Taurine
Pharmacological effects
Ethanol
IT HAS BEEN reported [171 that acute, simultaneous injection of taurine (2-aminoethanesulfonic acid) reduces ethanol induced sleep time of mice. This reduction was substantially greater than that produced by 9 other amino acids which were administered at a similar concentration. Several possible mechanisms may underlie this antagonism. For example, it has been postulated that taurine is a neuromodulator or inhibitory transmitter. In support of these hypotheses are the following: iontophoretically administered taurine causes a depressor effect on most neurons [5, 6, 12, 14]; taurine appears to be concentrated in synaptosomal fractions [7,29] (though it is possible that it occurs within glia cells [91); it can be released by chemical and electrical stimulation [ 18] and be taken up into brain slices [201. Taurine may be a membrane stabilizer on the basis of data from the sacroplasmic reticulum from rat skeletal muscle wherein taurine caused an increase in the rate of calcium oxalate uptake, an increase in the total calcium sequestered, and a decrease in the rate of calcium transport after treatment of the preparation with phospholipase C 116]. An increase in the mitochondrial binding of calcium after taurine has also been reported [81. Furthermore, taurine in the intact dog heart prevents the efflux of potassium which accompanies large doses of epinephrine [25J. Much of this work has been summarized I3,4]. A third possible mechanism for the reduction of ethanol induced sleep time by taurine was suggested by lida and Hikichi [ 171. They speculated that taurine may form a complex with ethanol or acetaldehyde or increase the metabolic rate of ethanol. One purpose of our investigation was to examine the effect of taurine on circulating levels of ethanol. Since taurine did antagonize the effects of ethanol on sleep time 117] we questioned whether taurine would also antagonize some of the other reported effects of ethanol. Specifically, we attempted to replicate the effect of taurine on ethanol induced sleeping time and to study its effects on
ethanol induced decreases in body temperature I 11, 26, 321, seizure susceptibility II, 23, 36], and increase in brain 5-hydroxyindole acetic acid 1311. METHOD Adult male C57BL/6J mice purchased from the Jackson Laboratories (Bar Harbor, Maine) were used in these studies. All animals were housed 5 per cage in a 7:00 p.m.7:00 a.m. dark-light cycle with continuous access to water and Wayne Mouse Breeder Blox. The mice were randomly assigned to the experimental groups and each animal was used only once. In every experiment, each taurine solution was adjusted to pH 7.0 with dilute NaOH.
ltturine and Ethanol Induced Sleeping Time Mice were fasted overnight with continuous access to HeO. At 10 a.m. the next morning they were injected intraperitoneally with ethanol (3.5 g/kg, 0.2 ml/10 g body wt. prepared from 95%. ethanol) or with ethanol plus taurine (45 mg/kg; 0.2 ml/10 g body wt.). Sleeping time was measured as the total elapsed time from the initial loss of righting reflex to the animals" return without remission to all 4 feet. The righting reflex was considered lost if the animal, when placed on its back, did not right itself. The sleep time experiment was conducted in a constant temperature room 25 _+ 0.1°C and was repeated 3 times. The data were analyzed by t-tests.
Taurine attd Ethanol Induced Hypothermia Baseline rectal temperatures of mice were taken by inserting a small animal probe attached to a telethermometer (Yellow Springs Instrument, Model 43TA) approximately 3 cm into the colon. The animals were lightly restrained by the tail during this procedure, lnitial mean rectal temperatures of the groups were determined to be equal prior to the onset of the experiments. The mice were then injected with ethanol (2 g/kg: 0.2 ml/10 g body wt.) or with ethanol plus taurine (30
'This work was supported by a research grant No. AA01865 to William O. Boggan from the National Institute on Alcohol Abuse and Alcoholism. -'Department of Psychiatry and Behavioral Sciences and Biochemistry, Medical University of South Carolina, Charleston. SC.
C o p y r i g h t ' 1978 A N K H O I n t e r n a t i o n a l !nc.--0091-3057/78/100469-04500.80/0
470
B O G G A N E 7 AI,. b e e n p r e v i o u s l y s h o w n to be the optimal time Io see the i n c r e a s e in brain 5 - H I A A after E T O H I311. T h e b r a i n s were a n a l y z e d for 5 - h y d r o x y t r y p t a m i n e {5-HT) a n d 5-H1AA by the m e t h o d o f J o n s s o n and L e w a n d e r 1191. T h e s e data were a n a l y z e d by a n a l y s i s of vltriance a n d t-tests.
mg/kg: 0.2 ml/10 g b o d y wt. : this dose of t a u r i n e w a s c h o s e n for this e x p e r i m e n t b e c a u s e h i g h e r d o s e s were f o u n d to prod u c e h y p o t h e r m i a by t h e m s e l v e s ) . T h e t e m p e r a t u r e was t a k e n again 30, 60, 121) and 240 min after injection. T h e s e studies were carried out in a c o n s t a n t t e m p e r a t u r e room of 25 _, 0. I°C a n d the data were a n a l y z e d by a n a l y s i s of varia n c e on r e p e a t e d m e a s u r e s .
RESUI.IS T a u r i n e significantly r e d u c e d the sleeping time of a n i m a l s receiving e t h a n o l . E t h a n o l ( N - 2 3 ) - 4 7 . 3 +_ 5.5 rain: E t h a n o l plus T a u r i n e I N - 2 3 ) - 2 5 . 9 - + 3.6 min, r ~3.18, p < 0 . 0 0 3 . Data are given as m e a n _+ S.E. A l t h o u g h e t h a n o l a d m i n i s t r a t i o n d e c r e a s e d body temp e r a t u r e as a f u n c t i o n o f time F ( 2 . 2 8 ) - 6 3 . 2 5 . p - : 0 . 0 1 , t a u r i n e did not a n t a g o n i z e t h e s e effects f l ' a b l e I). T a u r i n e also failed to a n t a g o n i z e the effects of e t h a n o l on c l e c t r o c o n vulsive s h o c k {Table 2) and to alter the a m o u n t o f circulating e t h a n o l ~Tablc 1). E t h a n o l p r o d u c e d a significant (p
