The Effect of Gamma-Hydroxybutyrate on Nocturnal and Diurnal Sleep ...

Sleep 13(1):24-30, Raven Press, Ltd., New York © 1990 Association of Professional Sleep Societies

The Effect of Gamma-Hydroxybutyrate on Nocturnal and Diurnal Sleep of Normal Subjects: Further Considerations on REM Sleep-Triggering Mechanisms O. Lapierre, J. Montpiaisir, M. Lamarre, and M. A. Bedard Centre d'Etude du Sommeil, Hopital du Sacre-Coeur, Montreal, Quebec, Canada

Summary: Gamma-hydroxybutyrate (GHB) is a drug currently used to treat narcolepsy. The present study documents its effect on sleep organization in healthy subjects. GHB and a placebo were given at bedtime and before a morning nap in a double-blind fashion. GHB administered before nocturnal or diurnal sleep increases stages 3 and 4 and decreases stage 1 non-rapid eye movement (NREM) sleep. In addition, GHB improves REM efficiency at night and reduces wake time after sleep onset when administered before a morning nap recording. GHB also slightly decreases REM latency when administered in the morning, and this effect is correlated with age. Hypotheses regarding mechanisms of action of GHB and the involvement of hypothalamic structures in the regulation of REM sleep are discussed. Key Words: GHB-REM sleepNap-Hypothalamus.

Gamma-hydroxybutyrate (GHB), a naturally occurring metabolite of the mammalian brain (1,2), produces behavioral and biochemical effects when administered orally. GHB was first used clinically as an anesthetic agent (3). Its current clinical use is restricted to the treatment of narcolepsy. The effect of GHB on sleep varies from species to species: it has a potent rapideye-movement (REM)-inducing effect in cats (4,5), but not in rats (6,7) or rabbits (8). In humans, a shortened REM latency occurs during nighttime sleep after GHB administration in subjects with affective disorders (9) or narcolepsy (10), two conditions in which short REM latencies already exist before treatment (11-13). In healthy subjects, REM sleep facilitation is reported after neither diurnal (14,15) nor nocturnal GHB administration (15). The aim of the present study was to document further the effect of GHB on sleep in healthy subjects in a double-blind cross-over study. Special attention was given to the facilitation of REM sleep by GHB. REM sleep is known to follow a circadian cycle, Address correspondence and reprint requests to Dr. Jacques Montplaisir, Centre d'Etude du Sommeii, Hopitai du Sacre-Coeur, 5400 boul. Gouin Ouest, Montreal, (Quebec), H4J lCS Canada.

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GHB AND REM SLEEP IN NORMALS

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with an acrophase in the morning (16). Furthermore, an inverse relationship between REM latency and age has been reported by several authors (17,18); the effect of age and of time of administration was therefore measured. MATERIALS AND METHODS Subjects Twelve subjects, six men and six women, aged 23-63 years (mean 36.9 ± 3.9), entered the study. All were free of a past history or current symptoms of psychopathology, as well as of any medical condition known to influence sleep. None had taken psychotropic medication during the 6 months preceding the study, and none reported symptoms of narcolepsy or of any other sleep disorder. In addition, sleep apnea syndrome and periodic movements in sleep (PMS) were ruled out by all-night polysomnographic (PSG) recordings. Drug administration and experimental-procedure A single oral dose of 2.25 g GHB or placebo was administered in a double-blind fashion 15 min before each nocturnal and diurnal PSG recording. These PSG recordings were performed for two consecutive nights. Mter the second night, a nap was recorded from 10:00 a.m. to noon. This protocol was carried out under each drug condition, at an interval of 1 week. The order of administration (GHB versus placebo) was reversed for half the subjects. During each recording session, central electroencephalogram (C3/A2), electrooculogram (EOG), and chin electromyogram (EMG) were recorded. In addition, oral and nasal airflow, respiratory movements, and EMG activity of right and left anterior tibialis muscles were monitored during the first placebo and GHB recording nights. Sleep was recorded and scored according to a standard method (19) using 20-s epochs. Sleep onset was defined as the first occurrence of three consecutive epochs of stage 1 or one epoch of any other sleep stage. REM latency was measured from sleep onset, and stage REM periods were defined as subsequent epochs of REM sleep not separated by more than 15 min of another sleep stage or of waking. REM efficiency was defined as the percentage of the REM period spent in stage REM. Slow-wave sleep stage (SWS) was defined as stages 3 and 4 non-REM sleep. Statistical analysis The results of polygraphic recordings obtained after GHB administration were compared with those obtained after placebo administration using paired t tests. Only results of the second night of each PSG session and those of the nap recordings were considered for statistical comparison. RESULTS Nocturnal recordings (Table 1) GHB had no effect on total sleep time (TST), but the percentage of time spent in SWS (SWS%) increased significantly, whereas the percentage spent in stage 1 (stage 1%) decreased and the percentage spent in stage 2 (stage 2%) remained unchanged. These changes were confined to the first third of the night. Sleep latency decreased, although not significantly, after GHB administration. On the other hand, SWS latency shortened significantly. Sleep, Vol. 13, No.1, 1990

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O. LAPIERRE ET AL. TABLE 1. Nocturnal recordings (mean ± SEM) Placebo

TST (min) Sleep latency (min) SWS latency (min) REM latency (min) WASO(min) Stage 1% Stage 2% SWS% REM% REM efficiency (%) REM 1 efficiency (%) REM 2 efficiency (%) REM 3 efficiency (%) a

p ",:; 0.05.

b

P ",:; 0.01.

440.2 8.2 24.7 81.1 26.4 10.1 59.1 10.5 20.2 73.3 68.0 84.4 76.0

± ± ± ± ± ± ± ± ± ± ± ± ±

5.7 2.2 3.6 10.8 4.1 1.3 2.4 2.2 1.4 3.5 5.2 3.0 3.2

GHB 432.8 5.3 16.7 84.3 34.2 8.1 60.5 13.6 17.7 80.5 87.5 84.0 72.5

± ± ± ± ± ± ± ± ± ± ± ± ±

8.3 1.0 2.1 13.7 8.6 0.8 1.9 2.6 1.6 2.8 3.7 2.9 4.6

t-Test NS NS b

NS NS NS NS b

NS NS

NS, nonsignificant.

No difference was found in REM latency and th,e percentage spent in REM sleep (REM%) after GHB administration. REM efficiency increased significantly after GHB; looking at each REM period separately revealed that REM efficiency improved for the first REM period only (REM 1 efficiency). No worsening of REM efficiency was seen during the following REM periods. No pathological PMS or sleep apnea was found after GHB administration. None of the subjects reported sleep paralysis or hypnagogic hallucinations. Nap recordings (Table 2) Nap recordings revealed consolidation of sleep after treatment with GHB, with a significant decrease in wake time after sleep onset (W ASO) and percentage of time spent in stage 1 sleep. A nonsignificant increase in percentage of time spent in SWS and reduced REM latency also occurred during morning nap recordings. Individual results revealed that all subjects over the age of 40 (n = 6) experienced a marked reduction of REM latency with GHB. Pearson correlation coefficients were calculated between age and changes induced by GHB on each sleep variable listed in Table 2. A coefficient TABLE 2. Morning nap recordings (mean ± SEM) Placebo TST (min) Sleep latency (min) SWS latency (min) REM latency (min) WASO (min) Stage 1% Stage 2% SWS% REM% REM efficiency (%) p < 0.05. b P < 0.01. NS, nonsignificant.

a

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87.5 ± 7.6 10.0 ± 3.4 59.6 ± 6.3 57.6 ± 9.9 20.7 ± 5.6 19.1 ± 2.5 62.6 ± 4.2 6.5 ± 2.2 11.6±3.4 74.7 ± 8.5

GHB 106.0 9.3 39.8 41.3 7.3 8.6 39.8 9.2 15.6 78.1

± ± ± ± ±

± ± ± ± ±

10.5 3.8 7.5 11.3 2.2 2.4 7.5 2.6 3.1 8.1

t-Test NS NS NS NS NS NS NS NS


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correlation of 0.69 (p < O.OS) was found for REM latency, indicating that GHB decreases REM latency with advancing age. Changes of other sleep variables were not significantly correlated with age. DISCUSSION GHB and SWS GHB increased the duration of nocturnal SWS at the expense of stage 1 non-REM sleep. This observation was made previously in normal (14,IS), depressed (9), and narcoleptic (10) human subjects, although none of these studies used GHB and placebo in a double-blind fashion. It has been questioned whether delta activity induced by GHB represents physiological SWS or a drug effect, as delta activity was seen also in the waking state (10,14,IS). In the present study, no delta activity was seen during wakefulness before sleep onset or upon awakening during the night. Further studies should include EEG spectral analysis during waking in subjects treated with GHB. GHB and REM sleep GHB significantly improved the efficiency of the first REM period during nocturnal sleep recordings. During morning nap recordings, there was no significant increase in REM efficiency due to the large standard deviation. GHB reduced REM latency during morning nap recordings, and this effect increases with advancing age. REM sleep shows a stnmg circadian distribution, with an acrophase in the morning. In subjects submitted to a 90-min sleep-wake schedule, REM periods appear chiefly from 7:30 a.m. to 2:00 p.m. (16). This circadian distribution is also shown by shorter REM latencies during morning sleep recordings (20). REM latency is also known to decrease with age (17,18). In previous studies of GHB in healthy human subjects, age was either not mentioned (14) or ranged from 20 to 33 years old (1S). The effect of GHB on REM sleep, restricted to older subjects upon morning administration thus seems to follow a physiological trend. Brain mechanisms involved in the regulation of REM sleep There is general agreement that the neural structures responsible for the major tonic and phasic events of REM sleep are located in the brainstem and that the cholinergic system plays an important role. Most substances known to influence REM latency work through cholinergic mechanisms (21-2S). Injection of a variety of cholinergic agonists into various brainstem regions indicates that there is a localized region within the pontine reticular formation from which REM sleep can be most readily triggered (21,26-28). GHB has no cholinomimetic effect and even depresses the activity of cholinergic neurons whose terminals lie in the striatum and the hippocampus (29). Moreover, pretreatment with atropine, a muscarinic anticholinergic agent known to suppress REM sleep when administered alone (30), does not prevent the facilitation of REM sleep following GHB administration (31). REM sleep is also facilitated by a decrease of serotonin (S-HT) or norepinephrine (NE) neuronal activity in the brainstem. However, GHB has little effect on brain S-HT or NE content in rats (32). More recently, a similar experiment (33) was conducted with -v-hydroxybutyric acid, and no changes in the concentration of S-HT were observed in the hemispheres, the hypothalSleep, Vol. 13, No.1, 1990

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O. LAPIERRE ET AL.

amus, or the brainstem, and a decrease of NE content was seen only in the hypothalamus. There are some indications that in addition to the brainstem cholinergic mechanisms, a more rostral control system, possibly located in the hypothalamus, may modulate REM sleep. Tumor of the rostral brainstem and hypothalamus (34,35), adenoma of the pituitary (36), and surgical lesion involving the perichiasmal hypothalamus (37) have all been found to produce sleep onset REM periods, muscular atonia, sleep paralysis, or hypnagogic hallucinations. These symptoms encountered in narcolepsy may represent dissociated manifestations of REM sleep. There are also physiological indications, based mainly on the work of Jouvet (38), showing a suppression of REM sleep in pontine cats (without "ilot hypothalamique") and restoration of REM sleep after daily administration of posterior and intermediate pituitary extracts. Jouvet proposed that hypothalamic structures, and particularly the arcuate nuclei, synthesize a factor responsible for REM sleep. Dopaminergic neurons are present in the hypothalamus (39) and may be involved in the regulatory mechanism of REM sleep at this level. GHB mode of action The exact site of action of GHB is unknown. Some observations favor the brainstem, e.g., the ability ofGHB to induce REM sleep in pontine and mesencephalic cats (4) and the presence of GHB binding (40) and synthesis sites (41) in the brainstem. However, a more recent study (42) showed that the brainstem was practically devoid of highaffinity binding sites for GHB. GHB binding (40,42) and synthesis sites (41) have also been found in the hypothalamus. In addition, intravenous administration of a low dose of GHB (2.5 g) increases the plasma prolactine level (43). This action could be due to the release of the inhibitory control of dopaminergic tuberoinfundibular neurons on prolactine secretion in the hypothalamus. Consequently, hypothalamic structures may mediate the effect of GHB. However, it should be stressed that the highest densities ofGHB binding sites are found in various regions of the limbic structure, especially field CA-l of Ammon's horn (42). This region may playa role in the physiopathology of cataplexy, a symptom triggered by specific emotions and controlled by GHB (10). Further research is necessary to clarify this issue. The mechanism of action of GHB is not fully understood, but it is known that GHB depresses dopaminergic neurons in the extrapyramidal system (44) as well as in the hypothalamus (39). The exact role of dopaminergic neurons in sleep is still controversial. Several observations suggest that dopamine may have an inhibitory effect on REM sleep. Dopamine receptor agonists reduce or even abolish REM sleep in humans (45) and can prevent the REM rebound that normally follows REM sleep deprivation in cats (46). Intravenous infusion of L-DOPA during NREM sleep delays the onset of REM sleep in humans (47). Dopamine receptors, number of cell bodies, and level of neurotransmitter and biosynthetic enzymes all decrease with age (48). This reduced dopaminergic transmission, along with the decrease in DA release caused by GHB, may explain the shortened REM latency observed in older subjects after GHB. GHB REM induction test GHB has a facilitative effect on REM sleep, but this effect seems to be restricted to populations specifically sensitive to REM induction, namely, subjects with narcolepsy or major affective disorders (9,10). It is suggested that response to GHB may help in the Sleep, Vol. 13, No.1, 1990


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diagnosis of these two conditions. It may reduce REM latency and even induce SOREMPs during diurnal sleep recordings in these patients. Recently, GHB was administered to subjects with major affective disorder (MAD) in remission; it markedly reduced REM latency (49). If replicated in a larger sample, this response to GHB may become a diagnostic tool in MAD and may represent a trait marker for this condition. Acknowledgment: This investigation was supported in part by the Medical Research Council of Canada.

REFERENCES 1. Bessman SP, Fishbein WN. Gamma-hydroxybutyrate, a normal brain metabolite. Nature 1963;200: 1207-8. 2. Roth RH, Giarman NJ. Nature occurrence of gamma-hydroxybutyric acid in mammalian brain. Biochem Pharmacol 1970;19: I 087-93. 3. Laborit H, Jouany JM, Gerard J, Fabiani F. Generalites concernant I'etude experimentale et I'emploi c1inique de gamma-hydroxybutyrate de sodium. Aggressologie 1960;1:397-405. 4. Jouvet M, Cier A, Mounier D, Valatx JL. Effets du 4-butyralactone et du 4-hydorxybutyrate de sodium sur I'EEG et Ie comportement du chat. CRS Soc Bioi (Paris) 1961;155:1313-6. 5. Matsuzaki M, Takagi H, Tokizane T. Paradoxical phase of sleep: its artificial induction in the cat by sodium butyrate. Science 1964;146:1328--9. 6. Marcus RJ, Winters WD, Mori K, Spooner CEo EEG and behavioral comparison of the effects of gamma-hydroxybutyrate, gamma-butyrolactone and short chain fatty acids in the rat. Int J Neuropharmacol 1967;6: 175-85. 7. Godschalk M, Dzoljic MR, Bonta IL. Slow wave sleep and a state resembling absence epilepsy induced in the rat by gamma-hydroxybutyrate. Eur J PharmacoI1977;44:105-11. 8. Godbout R, Pivik RT. EEG and behavioral effects of gamma-hydroxybutyrate in the rabbit. Life Sci 1982;31:739-48. 9. Mamelak M, Escriu JM, Stokan O. The effects of gamma-hydroxybutyrate on sleep. Bioi Psychiatry 1977;12:273-88. 10. Broughton R, Mamelak M. Effects of nocturnal gamma-hydroxybutyrate on sleep/waking patterns in narcolepsy-cataplexy. Can J Neurol Sci 1980;7:23-31. II. Hishikawa Y, Kaneko Z. Electroencephalographic study on narcolepsy. EEG Clin Neurophysiol 1965;18:249-58. 12. Dement WC, Rechtschaffen A, Gulevich G. The nature of the narcoleptic sleep attack. Neurology 1966;16:18--33. 13. Kupfer DJ, Foster FG. Interval between onset of sleep and rapid-eye-movement as an indicator of depression. Lancet 1972:ii:684-6. 14. Metcalfe DR, Emde RN, Stripe JT. An EEG-behavioral study of sodium hydroxybutyrate in humans. EEG Clin Neurophysiol 1966;20:506-12. 15. Yamada Y, Yamamoto J, Fujiki A, Hishikawa Y, Kaneko Z. Effect of butyrolactone and gammahydroxybutyrate on the EEG and sleep cycle in man. EEG Clin Neurophysiol 1967;22:558-62. 16. Carskadon MA, Dement WC. Sleep studies on a 90-minute day. EEG Clin NeurophysioI1975;39:145-55. 17. Feinberg I, Carlson V. Sleep patterns as a function of normal and pathological aging in man. J Psychiatr Res 1968;5:107-44. 18. Hayashi Y, Otomo E, Endo S, Watanake H. The all-night polygraphics for healthy aged persons. Sleep Res 1979;8: 122. 19. Rechtschaffen A, Kales A, eds. A manual of standardized terminology. techniques and scoring system for sleep stages of human subjects. Los Angeles: Brain Information Service/Brain Research Institute, University of California at Los Angeles, 1968. 20. Webb WB, Agnew HW, Sternthal H. Sleep in the early morning. Psychol Sci 1966;6:277-8. 21. Amatruda TT, Black DA, McKenna TM, McCarley RW, Hobson JA. Sleep cycle control and cholinergic mechanisms: differential effects of carbachol at pontine brain stem sites. Brain Res 1975;98:501-15. 22. Sitaram N, Wyatt RI, Dawson S, Gillin JC. REM sleep induction by physostigmine infusion during sleep. Science 1976;191:1281-3. 23. Gillin JC, Sitaram N, Mendelson WB, Wyatt RI. Physostigmine alters onset but not duration of REM sleep in man. Psychopharmacology 1978;58:111-4. 24. Spiegel R. Effects of RS-86, an orally active cholinergic agonist, on sleep in man. Psychiatry Res 1984;11:1-13.

Sleep, Vol. 13, No.1, 1990

30

O. LAPIERRE ET AL.

25. Berger M., Riemann D, Hochli D, Spiegel R. The cholinergic rapid eye movement sleep induction test with RS-86: state or trait marker of depression? Arch Gen Psychiatry 1989;46:421-8. 26. Silberman EK, Vivaldi E, Garfield J, McCarley RW, Hosbon JA. Carbachol triggering of desynchronized sleep phenomena: enhancement via small volume infusions. Brain Res 1980;191 :215-24. 27. Hobson JA, Goldberg M, Vivaldi E, Riew D. Enhancement of desynchronized sleep signs after pontine microinjection of the muscarinic agonist bethanechol. Brain Res 1983;275: 127-36. 28. Sakai K. Executive mechanisms of paradoxical sleep. Arch Thai Bioi 1988;126:239-57. 29. Sethy VH, Roth RH, Walters JR, Marini J, Van Woert MH. Effect of anesthetic doses of gammahydroxybutyrate on the acetylcholine content of rat brain. Arch Pharmacol 1976;259:9-14. 30. Jouvet M. The role of monoamines and acetylcholine-containing neurons in the regulation of the sleepwake cycle. Ergeb Physiul 1972;64: 166-307. 31. Delorme F, Riotte M, Jouvet M. Conditions de declenchement du sommeil paradoxal par les acides gras a chaine courte chez Ie chat pontique chronique. CR Soc Bioi (Paris) 1966;160: 1157-60. 32. Gessa GL, Varguin L, Crabai F, Boero GC, Caboni F, Camba R. Selective increase of brain dopamine induced by GHB. Life Sci 1966;5:1921-1930. 33. Miguez I, Aldegunde M, Duran R, Veira JAR. Effect of low doses of gamma-hydroxybutyric acid on serotonine, noradrenaline and dopamine concentrations in rat brain areas. Neurochem Res 1988;13: 531-3. 34. Anderson M, Salmon MV. Symptomatic cataplexy. J Neurol Neurosurg Psychiatry 1977;40:186-91. 35. Stahl SM, Layzer RB, Aminoff MJ, Townsend JJ, Feldon S. Continuous cataplexy in a patient with a midbrain tumor: the limp man syndrome. Neurology 1980;30: 1115-8. 36. Pritchard PB, Charlesten SC, Dreifuss FE, Skinner RL, Pickett JB, Biggs PJ. Symptomatic narcolepsy. Neurology 1983;33(suppl 2):239 37. Schwartz WJ, Stakes JW, Hobson JA. Transient cataplexy after removal ofa craniopharyngioma. Neurology 1984;34:1372-5. 38. Jouvet M. Paradoxical sleep: a study of its nature and mechanisms. In: Akert K, Bally C, Shade JP, eds. Sleep mechanisms, progress in brain research. Amsterdam: Elsevier, 1965:21-62. 39. Moore KE, Demarest KT. Tuberoinfundibular and tuberohypophyseal dopaminergic neurons. In: Ganong WF, Martini L, eds. Frontiers in neuroendocrinology. New York: Raven Press, 1982:161-90. 40. Snead OC, Liu CC. Gamma-hydroxybutyrate binding sites in rat and human brain synaptosomal membranes. Biochem Pharmacol 1984;33:2587-90. 41. Weissmann-Nanopoulos D, Rumigny JF, Mandel P, Vincendon G, Maitre M. Immunocytochemical localization in rat brain of the enzyme that synthesizes gamma-hydroxybutyrate acid. Neurochem Int 1982;4:523-9. 42. Hechler V, Wessmann D, Mach E, Pujol JF, Maitre M. Regional distribution of high-affinity y-[3Hlhydroxybutyrate binding sites as determined by radioautography. J Neurochem 1987;49:1025-32. 43. Takahara J, Yunoki S, Yakushiji W, Yamauchi J, Yamane Y, Ofuji T. Stimulatory effects of gammahydroxybutyric acid on growth hormone and prolactin release in humans. J Clin Endocrinol Metab 1977;44: 1014-7. 44. Walters JR, Aghajanian GK, Roth RH. Dopaminergic neurons: inhibition of firing by gammahydroxybutyrate. Proc Fifth Int Cong PharmacoI1972;600:100. 45. Cianchetti C. Dopamine agonists and sleep in man. In: Wauquier A, Gaillard JM, Monti JM, Radulouaki M, eds. Sleep: neurotransmitters and neuromodulators. New York: Raven Press, 1985:121-34. 46. Stenberg D, Porkka-Heiskanen T. Dopaminergic inhibition of paradoxical sleep in cats. Sleep Res 1987; 16: 149. 47. Gillin JC, Post RM, Wyatt RJ, Goodwin FK, Snyder F, Bunney WE. REM inhibitory effect of L-dopa infusion during human sleep. EEG Clin Neurophysiol 1973;35: 181-6. 48. Wong DF, Wagner HN, Dannals RF, et al. Effects of age on dopamine and serotonin receptors measured by positron tomography in the living human brain. Science 1984;226:1393-6. 49. Lapierre 0, Montplaisir J, Poirier G. GHB REM-induction test: a possible biological marker for depression. Sleep Res 1989;18:368.

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