Activation of cannabinoid type 1 receptors decreases the synchronization of local field potential oscillations in the hippocampus and entorhinal cortex and prolongs the interresponse time during a differential-reinforcement-of-low-rate task.

Marijuana intoxication impairs neurocognitive functions. Common side effects of consuming cannabis include time distortion and memory loss. However, the underlying neurophysiological mechanisms involved in these effects remain unclear. We hypothesized that communication between the hippocampal CA1 region and medial entorhinal cortex (MEC) is essential for the transmission of temporal-associated information. We used a differential-reinforcement-of-low-rate (DRL) task, which requires subjects to press a lever at an optimal time point, to correlate the distributions of interresponse time (IRT) with local field potentials (LFPs) recorded in the CA1 and MEC under the effects of a cannabinoid type 1 (CB1) receptor agonist. We used a DRL 10-s schedule and trained the rats to withhold for 10 s before pressing a lever. Our data showed that the percentage of 12.4- to 14-s IRT events rose after activation of CB1 receptors in the MEC. In addition, gamma amplitude synchronization and CA1 theta phase-MEC gamma amplitude coupling decreased during the 6- to 14-s IRT events. These results suggest that activation of CB1 receptors in the MEC disrupt the functional connectivity between the CA1 and the MEC. This inefficient communication may result in increased IRT during a DRL schedule. Overall, we postulate that marijuana intoxication impairs the communication between the CA1 and MEC and influences behavioral performances that require precise timing ability.

Activation of cannabinoid receptor type 1 impairs spatial and temporal aspects of episodic-like memories in rats.

The endocannabinoid system modulates many brain functions, including episodic memories, which contain memories of time and places. Most studies have focused on the involvement of the endocannabinoid system in spatial memory; however, its role in temporal memory is not well understood. Few studies have tested whether the unilateral endocannabinoid system is sufficient to modulate memory retrieval. Here, we tested whether type 1 cannabinoid receptors in the right hippocampal cornu ammonis area 1 region are enough to modulate the retrieval of episodic memories, specifically their spatial and temporal components. Because rats have innate preferences for displaced or old familiar objects, we changed the locations of "old familiar" and "recent familiar" objects in an open field and measured the rats' exploration times to evaluate spatial and temporal memory. To address the influence of the type 1 cannabinoid receptors on the retrieval of episodic-like memories, two doses of arachidonylcyclopropylamide, a selective type 1 cannabinoid receptor agonist, were infused into the cornu ammonis area 1 of rats ten minutes before the discrimination trials. We observed that rats injected with a low dose of arachidonylcyclopropylamide spent less time investigating displaced objects, suggesting spatial memory impairment, whereas those receiving a high dose explored old familiar objects less frequently, suggesting temporal memory impairment. This indicates that unilateral activation of type 1 cannabinoid receptors in the cornu ammonis area 1 impairs the spatial and temporal aspects of episodic memories. This research mimics the influence of marijuana intoxication effects in humans, such as spatial and temporal disintegration.

Slow gamma rhythms in CA3 are entrained by slow gamma activity in the dentate gyrus.

In hippocampal area CA1, slow (∼25-55 Hz) and fast (∼60-100 Hz) gamma rhythms are coupled with different CA1 afferents. CA1 slow gamma is coupled to inputs from CA3, and CA1 fast gamma is coupled to inputs from the medial entorhinal cortex (Colgin LL, Denninger T, Fyhn M, Hafting T, Bonnevie T, Jensen O, Moser MB, Moser EI. Nature 462: 353-357, 2009). CA3 gives rise to highly divergent associational projections, and it is possible that reverberating activity in these connections generates slow gamma rhythms in the hippocampus. However, hippocampal gamma is maximal upstream of CA3, in the dentate gyrus (DG) region (Bragin A, Jando G, Nadasdy Z, Hetke J, Wise K, Buzsaki G. J Neurosci 15: 47-60, 1995). Thus it is possible that slow gamma in CA3 is driven by inputs from DG, yet few studies have examined slow and fast gamma rhythms in DG recordings. Here we investigated slow and fast gamma rhythms in paired recordings from DG and CA3 in freely moving rats to determine whether slow and fast gamma rhythms in CA3 are entrained by DG. We found that slow gamma rhythms, as opposed to fast gamma rhythms, were particularly prominent in DG. We investigated directional causal influences between DG and CA3 by Granger causality analysis and found that DG slow gamma influences CA3 slow gamma. Moreover, DG place cell spikes were strongly phase-locked to CA3 slow gamma rhythms, suggesting that DG excitatory projections to CA3 may underlie this directional influence. These results indicate that slow gamma rhythms do not originate in CA3 but rather slow gamma activity upstream in DG entrains slow gamma rhythms in CA3.

A prolonged stress rat model recapitulates some PTSD-like changes in sleep and neuronal connectivity.

Chronic post-traumatic stress disorder (PTSD) exhibits psychological abnormalities during fear memory processing in rodent models. To simulate long-term impaired fear extinction in PTSD patients, we constructed a seven-day model with multiple prolonged stress (MPS) by modifying manipulation repetitions, intensity, and unpredictability of stressors. Behavioral and neural changes following MPS conveyed longitudinal PTSD-like effects in rats for 6 weeks. Extended fear memory was estimated through fear retrieval induced-freezing behavior and increased long-term serum corticosterone concentrations after MPS manipulation. Additionally, memory retrieval and behavioral anxiety tasks continued enhancing theta oscillation activity in the prefrontal cortex-basal lateral amygdala-ventral hippocampus pathway for an extended period. Moreover, MPS and remote fear retrieval stimuli disrupted sleep-wake activities to consolidate fear memory. Our prolonged fear memory, neuronal connectivity, anxiety, and sleep alteration results demonstrated integrated chronic PTSD symptoms in an MPS-induced rodent model.

Hypocretin in locus coeruleus and dorsal raphe nucleus mediates inescapable footshock stimulation (IFS)-induced REM sleep alteration.

Hypocretin (hcrt) is a stress-reacting neuropeptide mediating arousal and energy homeostasis. An inescapable footshock stimulation (IFS) could initiate the hcrt release from the lateral hypothalamus (LHA) and suppresses rapid eye movement (REM) sleep in rodents. However, the effects of the IFS-induced hcrts on REM-off nuclei, the locus coeruleus (LC) and dorsal raphe nucleus (DRN), remained unclear. We hypothesized that the hcrt projections from the LHA to LC or DRN mediate IFS-induced sleep disruption. Our results demonstrated that the IFS increased hcrt expression and the neuronal activities in the LHA, hypothalamus, brainstem, thalamus, and amygdala. Suppressions of REM sleep and slow wave activity during non-REM (NREM) sleep caused by the high expression of hcrts were blocked when a nonspecific and dual hcrt receptor antagonist was administered into the LC or DRN. Furthermore, the IFS also caused an elevated innate anxiety, but was limitedly influenced by the hcrt antagonist. This result suggests that the increased hcrt concentrations in the LC and DRN mediate stress-induced sleep disruptions and might partially involve IFS-induced anxiety.

Using Baseplating and a Miniscope Preanchored with an Objective Lens for Calcium Transient Research in Mice.

Neuroscientists use miniature microscopes (miniscopes) to observe neuronal activity in freely behaving animals. The University of California, Los Angeles (UCLA) Miniscope team provides open resources for researchers to build miniscopes themselves. The V3 UCLA Miniscope is one of the most popular open-source miniscopes currently in use. It permits imaging of the fluorescence transients emitted from genetically modified neurons through an objective lens implanted on the superficial cortex (a one-lens system), or in deep brain areas through a combination of a relay lens implanted in the deep brain and an objective lens that is preanchored in the miniscope to observe the relayed image (a two-lens system). Even under optimal conditions (when neurons express fluorescence indicators and the relay lens has been properly implanted), a volume change of the dental cement between the baseplate and its attachment to the skull upon cement curing can cause misalignment with an altered distance between the objective and relay lenses, resulting in the poor image quality. A baseplate is a plate that helps mount the miniscope onto the skull and fixes the working distance between the objective and relay lenses. Thus, changes in the volume of the dental cement around the baseplate alter the distance between the lenses. The present protocol aims to minimize the misalignment problem caused by volume changes in the dental cement. The protocol reduces the misalignment by building an initial foundation of dental cement during relay lens implantation. The convalescence time after implantation is sufficient for the foundation of dental cement to cure the baseplate completely, so the baseplate can be cemented on this scaffold using as little new cement as possible. In the present article, we describe strategies for baseplating in mice to enable imaging of neuronal activity with an objective lens anchored in the miniscope.

Deep Brain Stimulation Increases Seizure Threshold by Altering REM Sleep and Delta Powers During NREM Sleep.

We previously demonstrated that seizure occurrences at different zeitgeber times alter sleep and circadian rhythm differently. On the other hand, the synchronized delta wave of electroencephalogram (EEG) during non-rapid eye movement (NREM) sleep facilitates seizure, while the desynchronized EEG of rapid eye movement (REM) sleep suppresses it. We also elucidated that unilateral deep brain stimulation (DBS) of the anterior nucleus of thalamus (ANT) suppresses seizure recurrence. In the present study, we intraperitoneally injected pentylenetetrazol (PTZ, 40 mg/kg) for 14 consecutive days (PTZ kindling) to induce spontaneous seizure in rats, and a 30-min (delivered 10 min before each PTZ injection) or a 3-h DBS of unilateral ANT (delivered 1 h before each PTZ injection) was applied to suppress seizure. The frequency of DBS stimulation was 200 Hz and the electrical current consisted of biphasic square pulses with 50-µA intensity, 100-µs pulse width, and 4.1-ms stimulation interval. Our results found that PTZ-induced spontaneous seizure did not cause a significant change in the quantity of NREM sleep but suppressed the amount of REM sleep. Unilateral ANT DBS prolonged the onset latency of ictal seizure, decreased the spontaneous seizure duration, and increased the survival rate but did not change the amplitude of epileptiform EEGs during ictal period. Unilateral ANT DBS did not significantly alter NREM sleep but increased the amount of REM sleep. An analysis of the spectrograms of fast Fourier transform indicated that the intensities of all frequencies were enhanced during the PTZ-induced ictal period and the subsequent spontaneous seizure. Thirty minutes of unilateral ANT DBS suppressed the augmentation of low-frequency (<10 Hz) intensities during the spontaneous seizure induced by PTZ kindling. We further found that consecutive injections of PTZ progressively increased the enhancement of the delta powers during NREM sleep, whereas unilateral ANT DBS inhibited this progressive enhancement. It was also noticed that 30 min of ANT DBS exhibited a better efficacy in epilepsy suppression than 3 h of ANT DBS. These results elucidated that unilateral ANT DBS enhanced the seizure threshold by increasing the amount of REM sleep and decreasing the progressive enhancement of delta power during NREM sleep to suppress spontaneous seizure recurrences in PTZ kindling-induced epileptic rats.

Connectivity between nidopallium caudolateral and visual pathways in color perception of zebra finches.

Researchers demonstrated an elegant ability for red discrimination in zebra finches. It is interested to understand whether red activates exhibit much stronger response than other colors in neural network levels. To reveal the question, local field potentials (LFPs) was recorded and analyzed in two visual pathways, the thalamofugal and the tectofugal pathways, of zebra finches. Human studies demonstrate visual associated telencephalons communicate with higher order brain areas such as prefrontal cortex. The present study determined whether a comparable transmission occurs in zebra finches. Telencephalic regions of the thalamofugal (the visual Wulst) and the tectofugal pathway (the entopallium) with their higher order telencephalon, nidopallium caudolateral (NCL) were simultaneously recorded. LFPs of relay nuclei (the nucleus rotundus, ROT) of tectofugal pathway were also acquired. We demonstrated that LFP powers in the tectofugal pathway were higher than those in the thalamofugal pathway when illuminating blue lights. In addition, the LFP synchronization was stronger between the entopallium and NCL. LFPs also revealed a higher Granger causality from the direction of entopallium to NCL and from ROT to entopallium. These results suggest that zebra finches' tectofugal pathway predominately processing color information from ROT to NCL, relayed by entopallium, and blue could trigger the strongest response.

Delayed evoked potentials in zebra finch (Taeniopygia guttata) under midazolam-butorphanol-isoflurane anesthesia.

Avian animals are visually inclined, which has caused them to attract increasing attention for visual neurophysiology or electrophysiology studies, including the study of the visual evoked potential (VEP). VEP has developed into an investigative tool for understanding the physiology and the pathology of the visual pathway. Chemical restraint is a common method to minimize motion artifacts in animals when acquiring VEP data, but little is known about its influence on the signal in an avian animal. In addition, it is difficult to make comparisons between conscious state data when the animals are ultimately under anesthesia. Therefore, finding drugs and developing protocols that have an acceptable effect is valuable. We compared the local field potentials of physically and chemically restrained zebra finches (Taeniopygia guttata), a small avian species, to simulate a relatively challenging recording condition. Finches were sedated with midazolam-butorphanol, and anesthesia was maintained by isoflurane. Electrodes were implanted into the left nucleus rotundus, which is a visual nucleus in birds. The VEPs of the control group (N = 3) were recorded after they fully recovered and were restrained by towels. The other birds (N = 3) were recorded under anesthesia. The results show that without the visual stimuli, anesthesia generally suppressed the overall power of field potentials. However, by focusing on the spectra during VEPs, visual stimuli still triggered significant VEPs in frequencies below 30.8 Hz, which were even stronger than towel-restrained birds. The drugs also prolonged the latency of the VEP, increased the duration of the VEP when compared to towel-restrained birds. As regard to towel-restrained zebra finches, the field potentials were less synchronized and may need data preprocessing to have clear VEPs. In conclusion, the current study presents evidence of basic VEP for zebra finch under midazolam-butorphanol-isoflurane anesthesia with a protocol that is a safe and feasible anesthetic combination for chemical restraint, which is particularly useful for small animals when obtaining evoked potentials.

Hypocretin in median raphe nucleus modulates footshock stimuli-induced REM sleep alteration.

Stress is one of major factors that cause sleep problems. Hypocretin represents a stress-related neuropeptide and is well known in maintaining physiological wakefulness. The hypocretinergic neurons originate in the lateral hypothalamic area (LHA) and transmit to several brain regions, including the median raphe nuclei (MRNs). The MRNs modulate both fear responses and sleep-wake activity; however, it remains unclear whether stress alters the levels of hypocretin to regulate MRNs and consequently disrupt sleep. In this paper, we employed the inescapable footshock stimuli (IFS) as a stressor and hypothesized that the IFS-induced sleep disruption is mediated by increased hypocretins in the MRNs. Our results demonstrate that the concentrations of hypocretin in the hypothalamus increased after IFS. Rapid eye movement (REM) sleep was reduced after footshock, and microinjection of non-selective hypocretin receptor antagonist TCS-1102 into the MRNs blocked the IFS-induced decrease of REM sleep. Furthermore, administration of hypocretins into the MRNs mimicked the IFS-induced REM sleep reduction. These results conclude that the increased levels of hypocretins in the MRNs mediate the IFS-induced REM sleep reduction.

Protective Effects of Functional Chicken Liver Hydrolysates against Liver Fibrogenesis: Antioxidation, Anti-inflammation, and Antifibrosis.

Via an assay using an Amino Acid Analyzer, pepsin-digested chicken liver hydrolysates (CLHs) contain taurine (365.57 ± 39.04 mg/100 g), carnosine (14.03 ± 1.98 mg/100 g), and anserine (151.58 ± 27.82 mg/100 g). This study aimed to evaluate whether CLHs could alleviate thioacetamide (TAA)-induced fibrosis. A dose of 100 mg TAA/kg BW significantly increased serum liver damage indices and liver cytokine contents. Cell infiltration and monocytes/macrophages in livers of TAA-treated rats were illustrated by the H&E staining and immunohistochemical analysis of cluster of differentiation 68 (CD68, ED1), respectively. A significantly increased hepatic collagen accumulation was also observed and quantified under TAA treatment. A significant up-regulation of transforming growth factor-beta (TGF-ß) and SMAD family member 4 (SMAD4) caused by TAA treatment further enhanced alpha smooth muscle actin (αSMA) gene and protein expressions. The liver antioxidant effects under TAA treatment were significantly amended by 200 and 600 mg CLHs/kg BW. Hence, the ameliorative effects of CLHs on liver fibrogenesis could be attributed by antioxidation and anti-inflmmation.

Spatial Sequence Coding Differs during Slow and Fast Gamma Rhythms in the Hippocampus.

Spatiotemporal trajectories are coded by "theta sequences," ordered series of hippocampal place cell spikes that reflect the order of behavioral experiences. Theta sequences are thought to be organized by co-occurring gamma rhythms (∼25-100 Hz). However, how sequences of locations are represented during distinct slow (∼25-55 Hz) and fast (∼60-100 Hz) gamma subtypes remains poorly understood. We found that slow gamma-associated theta sequences activated on a compressed timescale and represented relatively long paths extending ahead of the current location. Fast gamma-associated theta sequences more closely followed an animal's actual location in real time. When slow gamma occurred, sequences of locations were represented across successive slow gamma phases. Conversely, fast gamma phase coding of spatial sequences was not observed. These findings suggest that slow gamma promotes activation of temporally compressed representations of upcoming trajectories, whereas fast gamma supports coding of ongoing trajectories in real time.

Disruption of footshock-induced theta rhythms by stimulating median raphe nucleus reduces anxiety in rats.

Theta rhythms generated in the hippocampus are controlled by the pacemaker in the medial septum-diagonal band of Broca (MS-DBB). The median raphe nucleus (MRN) transmits serotonergic signals to the MS-DBB, which suppresses the septo-hippocampus-produced theta waves, whereas GABAergic interneurons in the MRN facilitate the generation of theta oscillations. Animal studies have indicated that fear increases theta oscillations. Moreover, anxiolytics reduce reticular formation-elicited theta rhythms and theta blockade decreases anxiety. In this study, we hypothesized that the MRN mediates anxiety reduction caused by the theta blockade. Our results demonstrated that inescapable-footshock stimulation significantly increased the power of low-frequency theta oscillations (4-7 Hz) in rats. Both the electrical stimulation of MRN and administration of bicuculline into the MRN successfully desynchronized footshock-induced theta oscillations. Compared to the naïve rats, inescapable-footshock stimulation diminished the entry percentage and time spent in the open arms of the elevated plus maze (EPM), behavioral indicators of anxiety. Rats treated with either MRN stimulation or bicuculline administration to desynchronize theta oscillations reduced anxiety caused by the inescapable-footshock stimulation. Our results demonstrated that the electrical stimulation of MRN or blockade of the GABAergic pathways in the MRN interferes with theta oscillations and reduces anxiety, implicating the role of MRN.

Effect of cannabidiol on sleep disruption induced by the repeated combination tests consisting of open field and elevated plus-maze in rats.

Patients with post-traumatic stress disorder (PTSD) frequently complain of having sleep disturbances, such as insomnia and rapid eye movement (REM) sleep abnormality. Cannabidiol (CBD), a psycho-inactive constituent of marijuana, reduces physiological non-REM (NREM) sleep and REM sleep in normal rats, in addition to generating its anxiolytic effect. However, the effects of CBD on anxiety-induced sleep disturbances remain unclear. Because anxiety progression is caused by persistent stress for a period of time, we employed the repeated combination tests (RCT) consisting of a 50-min open field (OF) and a subsequent 10-min elevated plus-maze (EPM) for four consecutive days to simulate the development of anxiety. Time spent in the centre arena of OF and during open arms of the EPM was substantially decreased in latter days of RCT, suggesting the habituation, which potentially lessens anxiety-mediated behavioural responses, was not observed in current tests. CBD microinjected into the central nucleus of amygdala (CeA) significantly enhanced time spent in centre arena of OF, increased time during the open arms and decreased frequency of entry to the enclosed arms of EPM, further confirming its anxiolytic effect. The decrease of NREM sleep during the first hour and the suppression of REM sleep during hours 4-10 after the RCT represent the similar clinical observations (e.g. insomnia and REM sleep interruption) in PTSD patients. CBD efficiently blocked anxiety-induced REM sleep suppression, but had little effect on the alteration of NREM sleep. Conclusively, CBD may block anxiety-induced REM sleep alteration via its anxiolytic effect, rather than via sleep regulation per se. This article is part of a Special Issue entitled 'Anxiety and Depression'.

Activation of GABAergic pathway by hypocretin in the median raphe nucleus (MRN) mediates stress-induced theta rhythm in rats.

The frequency of electroencephalograms (EEGs) is predominant in theta rhythm during stress (e.g., footshock) in rats. Median raphe nucleus (MRN) desynchronizes hippocampal theta waves via activation of GABAergic neurons in the medial septum-diagonal band of Broca (MS-DBB), a theta rhythm pacemaker. Increased hypocretin mediates stress responses in addition to the maintenance of wakefulness. Hypocretin receptors are abundant in the MRN, suggesting a possible role of hypocretin in modulating stress-induced theta rhythm. Our results indicated that the intensity of theta waves was enhanced by footshock and that a hypocretin receptor antagonist (TCS1102) suppressed the footshock-induced theta waves. Administration of hypocretin-1 (1 and 10 µg) and hypocretin-2 (10 µg) directly into the MRN simulated the effect of footshock and significantly increased theta waves. Co-administration of GABA(A) receptor antagonist, bicuculline, into the MRN blocked the increase of theta waves induced by hypocretins or footshock. These results suggested that stress enhances the release of hypocretins, activates GABAergic neurons in the MRN, blocks the ability of MRN to desynchronize theta waves, and subsequently increases the intensity of theta rhythm.

Biphasic effects of baicalin, an active constituent of Scutellaria baicalensis Georgi, in the spontaneous sleep-wake regulation.

AIM OF THE STUDY: Baicalin is an active compound originating from the root of Scutellaria baicalensis Georgi, which has been used for anti-inflammation, anti-bacteria, anti-hypertension, anti-allergy and sedation since ancient China, though the neuronal mechanisms involved in the sedative effect is still unclear. Baicalin possesses the ability to decrease the expression of pro-inflammatory cytokines and nuclear factor (NF)-κB activity. Furthermore, baicalin has demonstrated an anxiolytic-like effect via activation of γ-aminobutyric acid-A (GABA(A)) receptors. Pro-inflammatory cytokines (e.g. interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-α) and the GABAergic system promote sleep. This study was designed to determine whether the GABA(A) receptor activation and/or the suppression of pro-inflammatory cytokines mediate(s) baicalin-induced sleep alterations. MATERIALS AND METHODS: Baicalin was intracerebroventricularly (ICV) administered 20 min either prior to the beginning of the light period or before the onset of the dark period. Electroencephalogram (EEG) and gross body movement were acquired for sleep analysis. Pharmacological blockade of IL-1 and GABA(A) receptors were employed to elucidate the involvements of IL-1 and GABA(A) receptors in baicalin-induced sleep alterations. IL-1ß concentrations obtained after baicalin administration in several distinct brain regions were determined by ELISA. RESULTS: ICV administration of baicalin decreased slow wave sleep (SWS) during the first 2h of the light period. Rapid eye movement sleep (REMS) was not altered. The blockade of IL-1ß-induced SWS enhancement by baicalin suggests that the antagonism of IL-1 receptors is involved in baicalin-induced SWS decrement during the light period. However, IL-1ß concentrations during the light period were not altered after baicalin administration. In contrast, baicalin increased both SWS and REMS during hours 8-10 of the dark (active) period when baicalin was administered at the beginning of the dark period, and its effects were blocked by the GABA(A) receptor antagonist bicuculline. CONCLUSION: Baicalin exhibits biphasic effects on sleep-wake regulation; the decrease of SWS during the light period and increases of SWS and REMS during the dark period. Inhibition of IL-1 action and enhancement of GABA(A) receptor activity may mediate baicalin's effects during the light and dark period, respectively.

TNF-NF-kappaB signaling mediates excessive somnolence in hemiparkinsonian rats.

Daytime somnolence is common in patients with Parkinson's disease (PD); however there is a lack of understanding of the cellular mechanisms involved in mediating these effects. It has been hypothesized that microglial activation and the subsequent increase of pro-inflammatory cytokines play an important role in the pathogenesis of PD. Because some cytokines are involved in the regulation of sleep, this study was designed to determine if tumor necrosis factor (TNF) and interleukin-1beta (IL-1beta), mediate daytime somnolence in the proteasome inhibitor (MG-132)-induced hemiparkinsonian rat model. Our results indicated that microglial activation caused the loss of dopaminergic neurons in the substantia nigra, and the expression of TNF-alpha, but not IL-1beta, increased in the midbrain and hypothalamus in MG-132-induced hemiparkinsonian rats. Slow-wave sleep (SWS) increased after the induction of hemiparkinsonism, but rapid eye movement (REM) sleep was not consistently altered. Application of the TNF receptor fragment (TNFRF) blocked hemiparkinsonism-induced SWS alteration, whereas the IL-1 receptor antagonist (IL-1ra) exhibited no effect. Increased nuclear translocation of NF-kappaB in the midbrain, and the blockade of SWS enhancement in MG-132-induced hemiparkinsonian rats by an inhibitor of NF-kappaB activation indicate that the TNF-NF-kappaB cascade is a critical mediator of MG-132 hemiparkinsonian-induced sleep alteration. This observation suggests potential therapeutic interventions to target the excessive daytime somnolence in patients with PD.