Polygraphic study of the effects of sodium 4-hydroxybutyrate and 4-butyrolactone in man

PhyMoh~x,y and Behavior. Vol. I, pp. 233-240. Pergamon Press Ltd., 1966 Printed in Great Britain

Polygraphic Study of the Effects of Sodium 4-Hydroxybutyrate and 4-Butyrolactone in Man CHIHIRO

OHYE AND TAKEO KUWABARA

Department of Neurosurgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan AND HISASHI YANAGIDA

AND NAOYA TACHIBANA

Department of Anesthesiology, Faculty of Medicine, University of Tokyo, Tokyo, Japan (Received 1 F e b r u a r y 1966) KUWABARA, H. YANAGIDAAND N. TACHIBANA.Polygraphicstudy of the effectsof sodium 4-hydroxybutyrate and 4-butyrolactone in man. PHYSIOL.BEHAV. 1 (3) 233-240, 1966.--Polygraphic observations were made after intravenous

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or intracarotid administration of sodium 4-hydroxy utyrate and 4-butyrolactone in man. At first theta bursts, then large continuous delta waves appeared in the EEG with increased EMG, accelerated respiration and heart rate. Consciousness was maintained. This was followed by irregular slow waves with reduced EMG, slow and stable respiration and heart rate, and a loss in consciousness. In 7 cases among 19, changes resembling paradoxical sl.eep were observed during this phase. The whole course of events was changed suddenly at two or three hr after the onset of injection. No disorientation or noticeable side effects were observed. When blood concentration of butyrate was measured and correlated with the polygraphic recordings, the continuous large slow wave stage corresponded to the peak of the blood concentration level while the irregular slow wave stage corresponded to the declining phase of the blood level curve. The effects of these compounds in producing continuous large slow waves without a disturbance of consciousness was emphasized. Polygraphic recording

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EXTENSIVE neurophysiological studies of sleep have clearly demonstrated the existence of a paradoxical phase of sleep in man as well as in other higher animals [8]. Recently, attempts have been made to induce paradoxical sleep by simple chemical compounds such as the short chain fatty acids. Jouvet et aL [9] and Matsuzaki et al. [13] claimed to have induced the paradoxical stage of sleep in the cat by intraperitoneal or intravenous administration of these compounds. However, Winters and Spooner [18] failed to obtain paradoxical sleep when these compounds were injected intraperitoneally and attributed Jouvet's observation [9] to subtle changes of the experimental environment. In man, these compounds have been used as an anesthetic [I, 11, 12, 14, 15]. They have certain advantages when used during surgery; maintenance of spontaneous respiration, no circulatory depressant action, normal total body oxygen consumption, and etc. Laborit et al. [11] and Schneider et aL [14] reported that the surgical anesthesia as well as behavioral and polygraphic results resembled natural sleep but they did not refer to it as paradoxical sleep. In the present study, we observed the polygraphic effects of sodium 4-hydroxybutyrate and 4-butyrolactone on patients with or without intracranial lesions. A special effort was made to test for hypnotic action and the possibility of inducing paradoxical sleep,

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METHODS

Sixteen adult men and women 16--50 yr of age were subjected to study. They included 4 cases of depressed fracture, 3 cases of skull defect and one each of meningioma, craniopharyngioma, pituitary adenoma, osteoma, cerebral contusion with epidural hematoma, neurinoma of the cervical root, head injury, Parry-Romberg's disease and neurosyphilis, respectively. In this group, observations were made apart from the operative procedures and some were examined two or three times. As for the results to be described there were no essential differences between polygraphic patterns before and after the neurosurgical operation. For polygraphic recording a 12 channel ink-writing electroencephalograph was used, Usually, bilateral frontal, temporal, parietal and occipital EEGs were led monopolarly by needle electrodes and were referred to the ears. Eye movements and E M G of the submental muscle were recorded also by needle electrodes inserted into the lateral part of the orbita or into the chin. Respiration was recorded by means of a thermister attached to the septum of the nasal cavity. E K G was led through plate electrodes pasted on the wrists. In some cases reflex plethysmography was done from the index finger. Two to four g (50mg/kg-100mg/kg) of sodium 4-hydroxybutyrate (GHB) or 4-butyrolactone (GBL) diluted into 233

234

OHYE, KUWABARA, YANAGIDA AND "rACHIBANA respiration and rapid eye movements indicating the paradoxical phase of sleep was observed during this stage. This irregular slow wave stage was interrupted by a sudden increase of E M G and the patient became conscious, Figure 1 illustrates typical sequential changes of the polygraph by injection of 4 g of GBL in 200 cc of saline solution dripped over 14 rain. Near the end of the dripping, the control EEG pattern in an awake state in Fig. I A gradually changed into a high amplitude theta dominant pattern as seen in B. At this time, heart rate and respiration were slightly accelerated. The tonic chin E M G decreased almost to zero. Then the high amplitude continuous delta wave pattern appeared in succession as seen in Fig. IC. The E M G activity was strikingly increased. An interesting finding was that in these B and C states, which continued for about 30 rain, the patient was still awake and verbal responses were usually possible and at this moment, high amplitude slow wave patterns abruptly changed to low voltage fast patterns as was also observed by Schneider el al. [14]. Some patients had nausea and vomiting with crying or moaning, though they could recall what happened during this period. After that, high amplitude continuous slow waves changed to irregular slow wave patterns as in Fig. ID. At this time, the E M G discharge gradually decreased and almost completely disappeared. Both the respiration and E K G were stable at a slower rate than the control state. The heart rate was 54/rain in A, 90/rain in B or C state and 42/rain in D in

200-400 cc of saline was injected into the vein of the upper extremity by a dripping method, pH of the solution being at 8.5. Dripping was performed for about 20 min. No premedication was used. During polygraphic recording, the patient was alone in a comfortable and clean examination room. In order to test the levels of the patient's consciousness, several external stimuli such as calling his name, pin prick to the arm or flashlight were used and their effects were observed from the outside through a window. In most cases, observation continued until the patient suddenly awoke spontaneously in about two to three hr after the intravenous administration. At the end of examination, we asked the patients about their own experiences. In one case during an abdominal operation blood levels of G H B were measured, (by a modified micromethod for determining short chain carboxylic acid esters, lactones, and anhydrides, based on their ability to react with hydroxylamine [3, 6]) at several time intervals after injection and were correlated with the polygraphic findings. In addition in two cases, an intracranial metastatic tumor of scalp cancer and an oligodendroglioma of the frontal lobe, we had the opportunity to administer GBL at the end of continuous arterial infusion of the anticancerous compound through the common carotid artery. RESULTS

the illustrated example. The patient never replied on calling his name, stimulations such as a pin prick or illumination were not effective in the EEG or behavioral pattern, apparently the patient was sleeping comfortably. This stage lasted for about one and a half or two hr. Slow EEG, regular E K G and respiration of a slow rate, abolished E M G and silent eye movements, together with the behavioral observations seemed to c o n s t i t u t e a state quite similar to natural sleep as was pointed out by Laborit [I I]. Often, irregular slow waves appeared to he intermingled with the low voltage fast waves. But gradually, these two

Pat/ern changes of polygraphic recordings In general, at about the end of intravenous administration, diffuse theta bursts appeared in the EEG and these were followed by large, continuous delta waves accompanied by an increase of E M G discharge. Behaviorally, the patient was still awake until the following period of irregular slow waves with reduced E M G . The irregular slow wave stage was most stable lasting for about 1-2 hr after the large rhythmic slow wave stage of about 30 rain. In some cases, low voltage fast EEG activity with silent EMG, irregular heart rate and

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FIG. 1. Polygraphic changes after intravenous administration of 4 g of GBL in a male patient 20 years old with a bone defect after head injury. From top to bottom; left and right frontal (LF, RF), temporal (LT, RT), parietal (LP, RP) and occipital (LO, RO) EEG, EKG, respiration (RESP), EMG of the chin (CHIN) and eye movements (EYE). A represents the control state; B was recorded about 15 rain after the injection, immediately after the whole amount was administered; C was at about 30 rain, note that the gain of all channels was reduced one half; D was about 90 rain later, E was recorded about 120 rain after the injection. The patient awoke spontaneously 15 rain after E. Calibration; 1 see and 50 gV. Sensitivity in C is reduced by one half.

BUTYRATE AND BUTYROLACTONE IN MAN

235

waves became separated and alternative. For about 30 sec to a few minutes low voltage fast waves were predominant, as shown in Fig. IE. As illustrated, E M G was silent, respiration was rather irregular. Except for the absence of rapid eye movements, these changes are those observed during the paradoxical phase of sleep. Figure 2 illustrates another example of the induced paradoxical sleep state by intravenous administration of 2 g of GBL (case L l in Fig. 3). The stage of low voltage fast waves with irregular slow waves as shown in Fig. 2A changed into a fast wave dominant phase as in Fig. 2B. This fast wave dominant phase lasted for about one min. The irregular amplitude in plethysmograph, irregular rhythm in heart rate, silent E M G , frequent rapid eye movements and suppressed respiration were noted as illustrated in Fig. 2B.

discharge, except for case L a which showed a retarded development of the EMG. This was followed by decreased or abolished E M G with an irregular slow EEG pattern resembling natural sleep (D stage). In 6 cases, short duration of low voltage fast EEG and irregular heart rate and respiration which could be recognized as the paradoxical phase of sleep (marked by P with an arrow) were observed. This state was observed most frequently at the end of the slow sleep pattern, several minutes prior to awakening. Rapid eye movements were observed only in two cases. Dreams were experienced in 5 cases which were marked by D ( + ) in Fig. 3. The contents of the dreaming varied between individuals, some dreamed a pleasant country view, some experienced a drama of ancient time, and some dreamed something terrible. Most of the patients did not complain of uncomfortable

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tracing), acccrelated EKG (8th tracing), abolished EMG of the chin (9th tracing), frequent and rapid eye movements (10th tracing) and irregular and suppr"~s:l respiration (I Ith tracing).

This stage was usually interrupted by a sudden increase of EMG discharge. The EEG did not return to an awake pattern but the slow waves persisted for ~ v e r a l minutes. When the EMG reappeared, the patient was able to answer our questions correctly. He reported that he had suffered from uncomfortable feelings at the initial stage and then fell asleep. This time he had no experience of dreaming. He knew correctly what was done to him and where he was at the moment when he had developed the EMG. Although a slight uncomfortable feeling remained, he could walk by himself. The EEG and E M G observations of the other 12 cases are represented schematically in Fig. 3. Seven cask's were administered G B L (Lt-L ~ in Fig. 3) and another 5 cases G H B ( A t - A ~ in Fig. 3). A, B, C, D and E in EEG column correspond to notations used in Fig. 1. In E M G column, the width of the bar corresponds approximately to the amount of E M G discharge. Duration of administration and amount of injected substances in g were shown on the third line of each case. Though the individual variations were inevitable, the sequences of the episodes were essentially the same in all eases. In the G B L group the dose was slightly less to induce the same changes. The first and most common change after administration of these compounds seemed to he the appearance o f continuous large slow waves in the EEG (B and C stag~) associated with tbe marked increase of E M G

feelings after spontaneous awakening from the induced sleep, though in several cams a somewhat drowsy state continued for a couple of hours, and in two cases severe headache and nausea remained. However, in general, it was characteristic of these compounds that no long duration conscious disturbance or disorientation resulted. It was also noteworthy that in contrast to other hypnogenic agents, administration of these compounds never led to a whole night's sleep even though most of the examinations were performed in the evening. Epileptic attacks or convulsive seizures were not experienced. When the time used for dripping or amount of the drug was changed, the typical polygraphic changes were not observable. In two cases, G H B was dripped within 7 (4g) and 8 (6g) rain respectively and the sequential changes of the polygraph were somewhat different. After about 30 rain of continuous delta bursts in the EEG with increased EMG, the EEG became flat with sporadic slow bursts patterns accompanied with reduced EMG. This state continued for 30 min to one hr. Then, gradually the fast component increased to become the usual sleep pattern. In another case, 2 g of G B L was dripped in 45 rain. Slow bursts on the background of irregular alpha appeared 30 rain after the start of dripping. It never developed to a continuous state and irregular alpha waves persisted predominantly for two and a half hours. The patient said after the

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Correlation between polygraphic/indings and the blood level of 6 ~ B In the case of a 35 year old female with abdominal wail herniation, blood level of GHB was measured. During the course of surgery under spinal anesthesia, 5 g of GHB was injected intravenously over 6 rain and the venous blood was tak~m at several time intervals. The concentration level in

the vein as a function of time and the respective polygraphic recordings are illustrated in Fig. 4. It reached a maximum value of 53 rag% after several minutes. At this time no chanBe was found polygraphically as shown in Fig. 4-2. But 5 rain later, slow wave b u n t s with increased EMG, irregular respiration and accelerated E K G were observed as in Fig. 4-3, blood level was decreasing. In this stage, the patient was still awake and was able to reply "yes" whenever we called her name, which was demonstrated in Fig. 4--4 with desynchronization of EEG, inc~__~__~dEM(3 and momentary irregular respiration. Shortly after this stage, the patient

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FIG. 4. Correlation between blood level of GHB and polygraphic results. Blood concentration of GHB s shown in m g ~ on the ordinate and plotted against the time from the start of injection in minutes on the abscissa. Polygraphic recordinBs (2-8) were obtained at the points indicated by the broken lines. Record I on the left illustrates control recordings. The arrow near the peak of the blood level curve indicates when the subject's name was called, but no answer was obtained. The other arrow on the right indicated a pinch applied to her arm which awakened her. Polygraphic recordings from bilateral frontal (LF, RF), temporal (LT, RT) and parietal (LP, RP) EEG, EMG of the chin (CHIN), eye movemenut (EYE), EKG, respiration (RESP) and plethysmogram (PL) are included. Small bar under the zero point indicatm duration of GHB administration. Calibration; I sec and 50 I~V. fell asleep suddenly and could not give an answer. This time is indicated by an upward thick arrow in Fig. 4. Thirty rain later, in the steep falling phase of the blood concentration curve, E E G showed irregular slow waves while the E M G discharge decreased, E K G and respiration became stable as shown in Fig. 4-5. Almost the same condition continued for about an hour as shown in Fig. 4-6, recorded 70 rain later. The changes of Fig. 4-7 were observed on the light falling s l o w o f the blood concentration curve, 100 rain after the start o f administration. Irregular slow waves were superimposed by low voltage fast waves and E M G decreased with more irregular respiration. Behaviorally the patient did not respond to any external stimulation during these stages. At 160 rain, the blood level being 16 mgyo, we gave a pinch to her arm and could awake her as in Fig. 4-8.

lntracarotid administration of GBL Intracarotid administration o f G B L was tried in two cases.

Four g of G B L was diluted in 200 cc of saline and injected slowly by manual compression o f the syringe with a speed of 6--10 cc/min through a catheter already implanted in a common carotid artery. In Fig. 5, the polygraphic changes o f the first case are demonstrated. In this case of a 50 year old housewife with an intracranial metastatic tumor of the scalp cancer, GBL was injected as stated above. The slow wave bursts appeared bilaterally two rain after the onset as shown in Fig. 5-1, only 0.28 g (6.7 mg/kg) being injected, while the patient was apparently normal in other polygraphic registrations as well as in her behavior. Within 10 min 1.8 g was injected, then the slow waves became continuous and the E M G decreased, heart rate (about 100/rain) and respiration (15/rain) were fairly regular and almost the same as the control level. The patient was still awake, answering quickly. Thereafter, delta waves became more compicuous than the theta waves and their amplitude larger. Twenty-five rain later when 2.5 g was

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injected, she had nausea with an increase of E M G , highly irregular respiration, slightly reduced heart rate o f 84/rain and large delta waves as illustrated in Fig. 5-2. Her respomes to questions were retarded. This lasted for 8 rain. When 3.6 g was injected, 32 rain after the onset, the injection was stopped because she did not answer, E M G discharge was reduced and an irregular sporadic slow E E G pattern developed. F r o m this moment, for about 50 rain, she was sleeping comfortably with sneezing, heart rate and respiration being stable and constant, 72/rain and 22/rain respectively, which are shown in Fig. 5-3. This was interrupted by short episodes of nausea accompanied by an increase in E M G discharge, quite irregular respiration, accelerated heart rate and large delta waves, which subsided in 5 rain and then the former pattern recurred. Ten rain later, E M G disappeared gradually while EEG was changing from a sleep pattern of irregular slow waves to the slow waves with a fast component o f 8 c/s. During this last stage, the irregularity in heart rate and respiration was not observed and indicated that there was no definite paradoxical sleep phase. The pattern is illustrated schematically in the lower part o f Fig. 5 in the same manner as in Fig. 3. In another case of a 33 year old man with an oligodendro* glioma in the left frontal lobe, the same compound was injected into the left common carotid artery in the same manner as in the first case. After 8 mitt from the start of

injection when 0.8 g (I 1.9 mg/kg) was used, the slow wave bursts developed for the first time and at this point the injection was terminated. Althoulih the course of change was different from the first caw,, especially in the amount of slow waves, he slept from 17-40 rain for 23 rain without any uncomfortable experiences. DISC"U~ON

The action of G H B or G B L seemed to be responsible for the inducement of continuous and high amplitude slow waves in the EEG. In all cases the first change in polygraphic recordings was the production of slow waves in the E E G and this slow wave pattern was obtained around the maximum level of the blood concentration of GHB. Further, on direct application o f the compound through the carotid artery, slow waves were produced by a much smaller amount of the compound than through intravenous administration. These investigations are consistent with and confirm the previous observations on the action o f the same compoumh in human subjects [I l, 14]. In general, slow waves in neocortical EEG are thought to indicate the cortical hypoactive state in contrast to low voltage fast waves of the aromal slate. In this study, however, slow waves induced b y these compounds are accompanied by an increased E M G ~ without a ~ n c e

BUTYRATE AND BUTYROLACTONE IN MAN of consciousness. This phase occurs against the paradoxical phase of sleep with respect to the EEG and behavior, and illustrates another type of dissociation. Similar dissociation o f EEG and behavior has been observed in the chronic animal after application of an anticholincrgic substance such as atropine which causes slow, high voltage synchronized EEG associated with excited or moderately active behavior [7, 16, 17]. In the present state, however, the mechanism responsible for these changes cannot be identified. In experiments on cats, slow waves with spindle bursts are known to be the initial change after intravenous or intraperitoneal injection of the same compounds [9, l I, 13, 14, 18]. Moreover, Drakontides et ai. [2] and Winters and Spooner [18] described excitement or the "head up" indicating increased E M G at this stage, a few minutes after the injection and prior to the paradoxical phase of sleep. If the initial changes between man and animal are compared, however, one can notice that in human cases the spindle bursts are lacking while the slow waves are more pronounced in amplitude and in the duration of the manifestation. This apparent discrepancy between man and animal may be due to a difference in species. In agreement with the observations by Laborit [11], our D stage in Fig. 1 has all the characteristics of physiological sleep not only in polygraphic recordings but also in the fact that this stage may include the paradoxical phase of sleep and in some cases dream experiences. Normal consciousness returns quickly without disorientation and noticeable side effects. Correlation of blood concentration of G H B and polygraphic observations revealed that a state resembling natural sleep appeared on the declining phase of the curve and suggested that some derivative o f the compound was responsible. In the G B L group, the slow wave stage occurred generally with a shorter latency from the onset of injection and with smaller doses than in the G H B group, and consequently the stage resembling natural sleep was introduced earlier in the former group than in the latter. This Coincides with the results obtained in the rat by Giarman and Roth [4] that onset of anesthesia after injection is earlier in the case of G B L (5-7 min) than G H B (8-12 rain). In terms of our results, however, the two opposite hypotheses proposed by Giarman and Roth [4] and by Helrich et al. [5] and Laborit [10] concerning the further metabolic pathways of G H B and the actual substance which causes physiological sleep is still an open question. A close relationship between the ~compounds and the artificial inducement of the paradoxical phase of sleep was not found in our study. This phase was observed in 7 cases out of 19, although it was o f a short duration of 30 sec to i min and rarely accompanied by rapid eye movements. The subtle differences between this phase and natural paradoxical sleep must be explained by the results of further studies.

239 SUMMARY

To investigate the hypnotic action of sodium 4-hydroxybutyrate (GHB) and 4-butyrolactone (GBL) in man, polygraphic observations were made on 19 human subjects, with special attention being paid to the possibility of the artificial inducement of the paradoxical phase of sleep. Intravenous dripping o f 50 mg/kg to 100 mg/kg of the compounds over 20 rain resulted in the following changes: theta bursts, then large continuous delta waves appeared in the EEG with increased E M G , accelerated respiration and heart rate. This phase which endured for about 30 rain was characterized by the fact that the patient was still awake in spite of the large delta activity. This was followed by a phase with irregular slow wave EEG, reduced E M G discharge, slow and stable respiration and heart rate during which the patient became unconscious. In 7 cases, changes resembling paradoxical sleep was observed during this phase, although rapid eye movements were rarely noticed. The irregular slow wave stage resembled natural sleep in various aspects. The whole course of changes was broken at two to three hr after the onset of injection by the sudden increase of E M G and the patient became conscious without disorientation and noticeable side effects, however a few complained of nausea and an uncomfortable feeling. With a small dose (2 g during 45 rain), only the theta bursts were induced while larger doses (4 or 6 g in 7 or 8 rain) led to a fiat E E G with sporadic delta waves. In one case, blood concentration of G H B was measured and correlated with polygraphic recordings; a continuous large slow wave stage corresponded to the peak of the blood concentration level, and a following irregular slow wave stage occurred during the declining phase of the blood level. In 2 cases, GBL was injected through the common carotid artery. It was shown that the initial E E G change occurred with a much smaller amount of the compound (6.7 mg/kg and 1i.9 mg/kg, respectively). It is suggested that these compounds produce primarily continuous large slow waves in the E E G without loss o f consciousness and then an hypnotic action by inducing a state quite similar to physiological sleep. ACKNOWLEDGMENTS

The authors are greatly indebted to Professor H. Yamamura, Department of Anesthesiology and Professor K. Sano, Department of Neurosurgery who gave us the opportunity and their encouragement throughout the study. They are also indebted to Professor T. Tokizane, Department of Neurophysiology, Institute of Brain Research for his advice and criticism. Their hearty thanks are due to Miss S. Tomiki and Miss K. Tanaka for their technical assistance. For the assessment of chemical compounds, they want to express many thanks to the members of the Central Research Laboratory, Sankyo Co. Ltd.

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