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210 BLOCKAGE OF DOPAMINERGIC D2 RECEPTORS PRODUCES A DECREASE IN REM BUT NOT IN SLOW WAVE SLEEP IN RATS
Abstracts of 3rd International Congress of the Association of Sleep Medicine (WASM) / Sleep Medicine 10, Suppl. 2 (2009) S1–S83
Objectives: To identify the possible involvement of tyrosine hydroxylase (TH) in rapid eye movement sleep deprivation (REMSD) we determined the motor behavioral and molecular alterations inflicted by reserpine associated to α-methyl-p-tyrosine (αMT) and rotenone after (REMSD) and rebound (R). Methods: Behavioral tests (catalepsy, grasping and open-field) were conducted to evaluate motor alterations inflicted by the drugs immediately after REMSD and R for the groups treated with reserpine (1 mg/kg) associated to αMT (250 mg/kg) to produce DA depletion, or rotenone (10 mg/kg) to increase DA turnover. In addition, the responses to these compounds were analyzed at a molecular level, using the expression of TH protein (assessed by western blot) and TH immunostaining as a marker of the number of dopaminergic neurons within the SNpc and striatum. Results: Pharmacological catecholaminergic extrusion occurred via the use of reserpine + αMT, suppressing voluntary movements, as reflected by the absence of ambulatory response and massive muscular rigidity. However, mice submitted to this pharmacological regimen plus REMSD presented a significant improvement in motor performance, including a total remission of rigidity. We present evidence that TH protein expression was downregulated in the SNpc by the influence of REMSD without affecting the number of dopaminergic neurons, and that this effect, per se, was not reflected in the striatum. Additionally, TH expression returned to baseline values after the R period. Moreover, catecholamine depletion promoted a spreading effect in the TH downregulation induced by REMSD, which extended towards the striatum, reverberating until the R period. Conclusion: We propose that the downregulation of TH expression produced by REMSD greatly explains the supersensitivity of dopaminergic D2 receptors, especially along the nigrostriatal pathway, and suggest a novel role of DA in the mediation of sleep-wake states as a consequence of the modulation of TH protein expression along that pathway.
210
BLOCKAGE OF DOPAMINERGIC D2 RECEPTORS PRODUCES A DECREASE IN REM BUT NOT IN SLOW WAVE SLEEP IN RATS
M.M.S. Lima 1 , M.L. Andersen 2 , A.B. Reksidler 3 , A. Silva 2 , A. Zager 2 , M. Vital 3 , S. Tufik 2 . 1 UFSC; 2 UNIFESP; 3 UFPR Introduction: Lately, dopamine (DA) has been singled out from the profusion of other neurotransmitters as a key substance in the regulation of the sleep–wake states. Objectives: We have hypothesized that blockage of dopaminergic D2 receptors by haloperidol could generate a reduction or even an ablation of rapid eye movement (REM) sleep. On the other hand, the use of the selective D2 agonist, piribedil, could potentiate REM sleep. Methods: We adopted haloperidol as a D2 antagonist and piribedil as a D2 agonist. Two distinct groups of animals, named REM sleep deprived (RSD) and non-sleep deprived (NSD) were surgically implanted with electrodes for electrophysiological recording. After one week, the animals were allocated for a 96 h of REM sleep deprivation protocol, and the animals from the NSD group were placed in their home cages. Subsequently to the RSD procedure, groups received a single intraperitoneal (i.p.) injection of saline 0.9% or haloperidol (3.0 mg/kg) or piribedil (8.0 mg/kg). Immediately afterwards the distinct groups initiated the sleep–wake evaluation for a period of up to 48 h, called the “rebound period”. In parallel, a different set of animals underwent the same experimental design to determine the protein expressions of D1, D2 and tyrosine hydroxylase (TH). Results: Electrophysiological findings demonstrate that D2 blockage produced a dramatic reduction in REM sleep during the rebound (REB) period after 96 h of REM sleep deprivation (RSD). This reduction in REM sleep was accompanied by an increment in SWS, which is possibly accounted for by the observed increase in the sleep efficiency. Conversely, our findings also demonstrate that the administration of piribedil did not generate additional increase in REM sleep. Additionally, D2 receptors were found to be downregulated in the haloperidol group after RSD, and subsequently up-regulated in the REB group, contrasting with the D1 down-regulation during the same period. Thus, the current data indicate a participation of the D2 receptors in REM sleep regulation and consequently, in the REM sleep/SWS balance. Conclusion: It is proposed that the mechanism underlying the striatal D2 up-regulation is consequence of RSD, which originally produces selective D2 supersensitivity, which is probably followed by a surge in D2 expression once RSD is over. In conclusion, we report a particular action of the dopaminergic neurotransmission in REM sleep relying on D2 activation.
211
S57
SLEEP DEPRIVATION ALTERS LIVER GLYCOGEN CONCENTRATIONS IN MALE MICE
L. Lungato, M.L. Gazarini, S. Tufik, V. D’Almeida. UNIFESP Human and animal studies have shown that serious metabolic alterations can be induced by sleep disturbances. Recent human studies reveal a widespread association between short sleep and diseases such as obesity and diabetes type 2. On the other hand, sleep-deprived rats also showed body weight loss and hyperphagia. Moreover, increase in energy demand and systemic effects are reinforced by decreases in organ weight, as verified after 96 h of sleep deprivation in rats. Objective: Since the liver plays a major role in energy metabolism and supplies other tissues with macronutrients, we studied the effects of 72 h of sleep deprivation on liver glycogen concentration and body weight in adult mice. Methods: Fourteen Swiss male mice were distributed among two groups: control (CRT) and sleep-deprived for 72 h by the modified multiple platform technique (SD). During the sleep deprivation protocol, animals were weighed daily. After sleep deprivation, the animals were sacrificed by cervical dislocation and liver samples were collected for measurement of glycogen content by extraction in alkaline medium followed by color reaction using a mixture of anthrone and sulfuric acid as chromogenic reagent. Results: We found statistically significant differences in body weight between groups during the 72 hours of sleep deprivation (+0.97 g versus -1.87 g for CT and SD respectively; Student’s t-test, p=0.038) and in the concentration of glycogen in liver (1.22 mg/100 g of tissue versus 0.73 mg/100 g of tissue for CT and SD respectively; Student’s t-test, p=0.001). Conclusions: These results provide information about metabolic changes induced by SD. Sleep deprivation produces a decrease in the body weight of mice followed by a decrease in the concentration of hepatic glycogen. These changes could be related to disturbances in other physiological functions, such as cognitive deficits, reduction in the integrity of the immune system, and hormonal disruption, since all these physiological, metabolic and cellular processes are dependent on energy which is supplied, at least in part, by hepatic glycogen. Support: FAPESP (CEPID 98/14303-3), CNPq, CAPES and AFIP.
212
A POSSIBLE METHOD FOR THE PREVENTION OF REM SLEEP NEED
L. Maisuradze 1 , N. Lortkipanidze 1 , T. Oniani 2 . 1 I.Beritashvili Institute of Physiology, Tbilisi, Georgia; 2 Georgian National Academy of Sciences Introduction: Pharmacological/non-pharmacological strategies for REMsleep deprivation have often been used in basic and clinical sleep research to understand REM-sleep regulation or to improve certain psycho-neurological conditions with enhanced REM-sleep need. However, the prevention of REMsleep propensity in most REM-sleep deprivation procedures still remains a problem in modern sleep neurophysiology. According to our previous data, the need for both REM-sleep and wakefulness is formed in slow-wave-sleep (SWS). Here we report on a method that enables REM-sleep removal without a subsequent increase in REM-sleep intensity. Methods: The sleep-wakefulness cycle (SWC) of mature male cats (n=6) chronically implanted with electrodes for EEG, EOG, EMG and ECG recordings was registered during basal, deprivation and recovery days. For the animal’s awakening from SWS, electrical stimulation of the posterior hypothalamus with various parameters (0.1-10 V; 0.1-5 ms; 0.2-500/s) was used in order to induce repeated EEG arousal (Experiment 1), and behavioral awakening (Experiment 2). SWC stages were scored in wakefulness (active and passive), SWS (light and deep) and REM-sleep. The frequency, duration and the percentage ratio of these stages were identified in deprivation and recovery days, and were compared to corresponding baseline data using Student’s t-test. Results: Depending on the specific electrical stimulation of the posterior hypothalamus, it was possible to evoke EEG or behavioral awakenings in the course of SWS. Accordingly, SWS restoration was observed in 10 or 20 seconds following cessation of stimulation. Though REM-sleep episodes appeared in the case of the EEG arousal, REM-sleep decreased in both frequency and duration. Repeated behavioral awakenings from SWS accompanied by two-min-lasting maintenance of active waking state led to a complete lack of REM-sleep onset, with no increase in REM-sleep intensity either in quantity or quality being observed during the recovery time. Conclusion: REM-sleep disappearance without a subsequent rebound, as
Objectives: To identify the possible involvement of tyrosine hydroxylase (TH) in rapid eye movement sleep deprivation (REMSD) we determined the motor behavioral and molecular alterations inflicted by reserpine associated to α-methyl-p-tyrosine (αMT) and rotenone after (REMSD) and rebound (R). Methods: Behavioral tests (catalepsy, grasping and open-field) were conducted to evaluate motor alterations inflicted by the drugs immediately after REMSD and R for the groups treated with reserpine (1 mg/kg) associated to αMT (250 mg/kg) to produce DA depletion, or rotenone (10 mg/kg) to increase DA turnover. In addition, the responses to these compounds were analyzed at a molecular level, using the expression of TH protein (assessed by western blot) and TH immunostaining as a marker of the number of dopaminergic neurons within the SNpc and striatum. Results: Pharmacological catecholaminergic extrusion occurred via the use of reserpine + αMT, suppressing voluntary movements, as reflected by the absence of ambulatory response and massive muscular rigidity. However, mice submitted to this pharmacological regimen plus REMSD presented a significant improvement in motor performance, including a total remission of rigidity. We present evidence that TH protein expression was downregulated in the SNpc by the influence of REMSD without affecting the number of dopaminergic neurons, and that this effect, per se, was not reflected in the striatum. Additionally, TH expression returned to baseline values after the R period. Moreover, catecholamine depletion promoted a spreading effect in the TH downregulation induced by REMSD, which extended towards the striatum, reverberating until the R period. Conclusion: We propose that the downregulation of TH expression produced by REMSD greatly explains the supersensitivity of dopaminergic D2 receptors, especially along the nigrostriatal pathway, and suggest a novel role of DA in the mediation of sleep-wake states as a consequence of the modulation of TH protein expression along that pathway.
210
BLOCKAGE OF DOPAMINERGIC D2 RECEPTORS PRODUCES A DECREASE IN REM BUT NOT IN SLOW WAVE SLEEP IN RATS
M.M.S. Lima 1 , M.L. Andersen 2 , A.B. Reksidler 3 , A. Silva 2 , A. Zager 2 , M. Vital 3 , S. Tufik 2 . 1 UFSC; 2 UNIFESP; 3 UFPR Introduction: Lately, dopamine (DA) has been singled out from the profusion of other neurotransmitters as a key substance in the regulation of the sleep–wake states. Objectives: We have hypothesized that blockage of dopaminergic D2 receptors by haloperidol could generate a reduction or even an ablation of rapid eye movement (REM) sleep. On the other hand, the use of the selective D2 agonist, piribedil, could potentiate REM sleep. Methods: We adopted haloperidol as a D2 antagonist and piribedil as a D2 agonist. Two distinct groups of animals, named REM sleep deprived (RSD) and non-sleep deprived (NSD) were surgically implanted with electrodes for electrophysiological recording. After one week, the animals were allocated for a 96 h of REM sleep deprivation protocol, and the animals from the NSD group were placed in their home cages. Subsequently to the RSD procedure, groups received a single intraperitoneal (i.p.) injection of saline 0.9% or haloperidol (3.0 mg/kg) or piribedil (8.0 mg/kg). Immediately afterwards the distinct groups initiated the sleep–wake evaluation for a period of up to 48 h, called the “rebound period”. In parallel, a different set of animals underwent the same experimental design to determine the protein expressions of D1, D2 and tyrosine hydroxylase (TH). Results: Electrophysiological findings demonstrate that D2 blockage produced a dramatic reduction in REM sleep during the rebound (REB) period after 96 h of REM sleep deprivation (RSD). This reduction in REM sleep was accompanied by an increment in SWS, which is possibly accounted for by the observed increase in the sleep efficiency. Conversely, our findings also demonstrate that the administration of piribedil did not generate additional increase in REM sleep. Additionally, D2 receptors were found to be downregulated in the haloperidol group after RSD, and subsequently up-regulated in the REB group, contrasting with the D1 down-regulation during the same period. Thus, the current data indicate a participation of the D2 receptors in REM sleep regulation and consequently, in the REM sleep/SWS balance. Conclusion: It is proposed that the mechanism underlying the striatal D2 up-regulation is consequence of RSD, which originally produces selective D2 supersensitivity, which is probably followed by a surge in D2 expression once RSD is over. In conclusion, we report a particular action of the dopaminergic neurotransmission in REM sleep relying on D2 activation.
211
S57
SLEEP DEPRIVATION ALTERS LIVER GLYCOGEN CONCENTRATIONS IN MALE MICE
L. Lungato, M.L. Gazarini, S. Tufik, V. D’Almeida. UNIFESP Human and animal studies have shown that serious metabolic alterations can be induced by sleep disturbances. Recent human studies reveal a widespread association between short sleep and diseases such as obesity and diabetes type 2. On the other hand, sleep-deprived rats also showed body weight loss and hyperphagia. Moreover, increase in energy demand and systemic effects are reinforced by decreases in organ weight, as verified after 96 h of sleep deprivation in rats. Objective: Since the liver plays a major role in energy metabolism and supplies other tissues with macronutrients, we studied the effects of 72 h of sleep deprivation on liver glycogen concentration and body weight in adult mice. Methods: Fourteen Swiss male mice were distributed among two groups: control (CRT) and sleep-deprived for 72 h by the modified multiple platform technique (SD). During the sleep deprivation protocol, animals were weighed daily. After sleep deprivation, the animals were sacrificed by cervical dislocation and liver samples were collected for measurement of glycogen content by extraction in alkaline medium followed by color reaction using a mixture of anthrone and sulfuric acid as chromogenic reagent. Results: We found statistically significant differences in body weight between groups during the 72 hours of sleep deprivation (+0.97 g versus -1.87 g for CT and SD respectively; Student’s t-test, p=0.038) and in the concentration of glycogen in liver (1.22 mg/100 g of tissue versus 0.73 mg/100 g of tissue for CT and SD respectively; Student’s t-test, p=0.001). Conclusions: These results provide information about metabolic changes induced by SD. Sleep deprivation produces a decrease in the body weight of mice followed by a decrease in the concentration of hepatic glycogen. These changes could be related to disturbances in other physiological functions, such as cognitive deficits, reduction in the integrity of the immune system, and hormonal disruption, since all these physiological, metabolic and cellular processes are dependent on energy which is supplied, at least in part, by hepatic glycogen. Support: FAPESP (CEPID 98/14303-3), CNPq, CAPES and AFIP.
212
A POSSIBLE METHOD FOR THE PREVENTION OF REM SLEEP NEED
L. Maisuradze 1 , N. Lortkipanidze 1 , T. Oniani 2 . 1 I.Beritashvili Institute of Physiology, Tbilisi, Georgia; 2 Georgian National Academy of Sciences Introduction: Pharmacological/non-pharmacological strategies for REMsleep deprivation have often been used in basic and clinical sleep research to understand REM-sleep regulation or to improve certain psycho-neurological conditions with enhanced REM-sleep need. However, the prevention of REMsleep propensity in most REM-sleep deprivation procedures still remains a problem in modern sleep neurophysiology. According to our previous data, the need for both REM-sleep and wakefulness is formed in slow-wave-sleep (SWS). Here we report on a method that enables REM-sleep removal without a subsequent increase in REM-sleep intensity. Methods: The sleep-wakefulness cycle (SWC) of mature male cats (n=6) chronically implanted with electrodes for EEG, EOG, EMG and ECG recordings was registered during basal, deprivation and recovery days. For the animal’s awakening from SWS, electrical stimulation of the posterior hypothalamus with various parameters (0.1-10 V; 0.1-5 ms; 0.2-500/s) was used in order to induce repeated EEG arousal (Experiment 1), and behavioral awakening (Experiment 2). SWC stages were scored in wakefulness (active and passive), SWS (light and deep) and REM-sleep. The frequency, duration and the percentage ratio of these stages were identified in deprivation and recovery days, and were compared to corresponding baseline data using Student’s t-test. Results: Depending on the specific electrical stimulation of the posterior hypothalamus, it was possible to evoke EEG or behavioral awakenings in the course of SWS. Accordingly, SWS restoration was observed in 10 or 20 seconds following cessation of stimulation. Though REM-sleep episodes appeared in the case of the EEG arousal, REM-sleep decreased in both frequency and duration. Repeated behavioral awakenings from SWS accompanied by two-min-lasting maintenance of active waking state led to a complete lack of REM-sleep onset, with no increase in REM-sleep intensity either in quantity or quality being observed during the recovery time. Conclusion: REM-sleep disappearance without a subsequent rebound, as