Amygdala opioid receptors mediate the electroacupuncture-induced deterioration of sleep disruptions in epilepsy rats.

BACKGROUND: Clinical and experimental evidence demonstrates that sleep and epilepsy reciprocally affect each other. Previous studies indicated that epilepsy alters sleep homeostasis; in contrast, sleep disturbance deteriorates epilepsy. If a therapy possesses both epilepsy suppression and sleep improvement, it would be the priority choice for seizure control. Effects of acupuncture of Feng-Chi (GB20) acupoints on epilepsy suppression and insomnia treatment have been documented in the ancient Chinese literature, Lingshu Jing (Classic of the Miraculous Pivot). Therefore, this study was designed to investigate the effect of electroacupuncture (EA) stimulation of bilateral Feng-Chi acupoints on sleep disruptions in rats with focal epilepsy. RESULTS: Our result indicates that administration of pilocarpine into the left central nucleus of amygdala (CeA) induced focal epilepsy and decreased both rapid eye movement (REM) sleep and non-REM (NREM) sleep. High-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints, in which a 30-min EA stimulation was performed before the dark period of the light:dark cycle in three consecutive days, further deteriorated pilocarpine-induced sleep disruptions. The EA-induced exacerbation of sleep disruption was blocked by microinjection of naloxone, µ- (naloxonazine), κ- (nor-binaltorphimine) or δ-receptor antagonists (natrindole) into the CeA, suggesting the involvement of amygdaloid opioid receptors. CONCLUSION: The present study suggests that high-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints exhibits no benefit in improving pilocarpine-induced sleep disruptions; in contrast, EA further deteriorated sleep disturbances. Opioid receptors in the CeA mediated EA-induced exacerbation of sleep disruptions in epileptic rats.

Activation of amygdala opioid receptors by electroacupuncture of Feng-Chi (GB20) acupoints exacerbates focal epilepsy.

BACKGROUND: The effect of seizure suppression by acupuncture of Feng-Chi (GB20) acupoints has been documented in the ancient Chinese literature, Lingshu Jing (Classic of the Miraculous Pivot), however, there is a lack of scientific evidence to prove it. This current study was designed to elucidate the effect of electroacupuncture (EA) stimulation of bilateral Feng-Chi (GB20) acupoints on the epileptic activity by employing an animal model of focal epilepsy. METHODS: Administration of pilocarpine into the left central nucleus of amygdala (CeA) induced the focal epilepsy in rats. Rats received a 30-min 100 Hz EA stimulation of bilateral Feng-Chi acupoints per day, beginning at 30 minutes before the dark period and performing in three consecutive days. The broad-spectrum opioid receptor antagonist (naloxone), µ-receptor antagonist (naloxonazine), δ-receptor antagonist (naltrindole) and κ-receptor antagonist (nor-binaltorphimine) were administered directly into the CeA to elucidate the involvement of CeA opioid receptors in the EA effect. RESULTS: High-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints did not suppress the pilocarpine-induced epileptiform electroencephalograms (EEGs), whereas it further increased the duration of epileptiform EEGs. We also observed that epilepsy occurred while 100 Hz EA stimulation of Feng-Chi acupoints was delivered into naïve rats. EA-induced augmentation of epileptic activity was blocked by microinjection of naloxone, µ- (naloxonazine), κ- (nor-binaltorphimine) or δ-receptor antagonists (natrindole) into the CeA, suggesting that activation of opioid receptors in the CeA mediates EA-exacerbated epilepsy. CONCLUSIONS: The present study suggests that high-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints has no effect to protect against pilocarpine-induced focal epilepsy; in contrast, EA further exacerbated focal epilepsy induced by pilocarpine. Opioid receptors in the CeA mediated EA-induced exacerbation of focal epilepsy.

Kappa-opioid receptors in the caudal nucleus tractus solitarius mediate 100 hz electroacupuncture-induced sleep activities in rats.

Previous results demonstrated that 10 Hz electroacupuncture (EA) of Anmian acupoints in rats during the dark period enhances slow wave sleep (SWS), which involves the induction of cholinergic activity in the caudal nucleus tractus solitarius (NTS) and subsequent activation of opioidergic neurons and µ-receptors. Studies have shown that different kinds of endogenous opiate peptides and receptors may mediate the consequences of EA with different frequencies. Herein, we further elucidated that high-frequency (100 Hz)-EA of Anmian enhanced SWS during the dark period but exhibited no direct effect on rapid eye movement (REM) sleep. High-frequency EA-induced SWS enhancement was dose-dependently blocked by microinjection of naloxone or κ-receptor antagonist (nor-binaltorphimine) into the caudal NTS, but was affected neither by µ- (naloxonazine) nor δ-receptor antagonists (natatrindole), suggesting the role of NTS κ-receptors in the high-frequency EA-induced SWS enhancement. Current and previous results depict the opioid mechanisms of EA-induced sleep.

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.

Endogenous opiates in the nucleus tractus solitarius mediate electroacupuncture-induced sleep activities in rats.

Electroacupuncture (EA) possesses various therapeutic effects, including alleviation of pain, reduction of inflammation and improvement of sleep disturbance. The mechanisms of EA on sleep improvement, however, remain to be determined. It has been stated in ancient Chinese literature that the Anmian (EX17) acupoint is one of the trigger points that alleviates insomnia. We previously demonstrated that EA stimulation of Anmian acupoints in rats during the dark period enhances non-rapid eye movement (NREM) sleep, which involves the induction of cholinergic activity in the nucleus tractus solitarius (NTS). In addition to cholinergic activation of the NTS, activation of the endogenous opioidergic system may also be a mechanism by which acupuncture affects sleep. Therefore, this study was designed to investigate the involvement of the NTS opioidergic system in EA-induced alterations in sleep. Our present results indicate that EA of Anmian acupoints increased NREM sleep, but not rapid eye movement sleep, during the dark period in rats. This enhancement in NREM sleep was dose-dependently blocked by microinjection of opioid receptor antagonist, naloxone, and the µ-opioid receptor antagonist, naloxonazine, into the NTS; administrations of δ-receptor antagonist, natrindole, and the κ-receptor antagonist, nor-binaltrophimine, however, did not affect EA-induced alterations in sleep. Furthermore, ß-endorphin was significantly increased in both the brainstem and hippocampus after the EA stimuli, an effect blocked by administration of the muscarinic antagonist scopolamine into the NTS. Our findings suggest that mechanisms of EA-induced NREM sleep enhancement may be mediated, in part, by cholinergic activation, stimulation of the opiodergic neurons to increase the concentrations of ß-endorphin and the involvement of the µ-opioid receptors.

Involvement of the mitochondrion-dependent pathway and oxidative stress in the apoptosis of murine splenocytes induced by areca nut extract.

Areca quid chewing is a major risk factor for oral submucous fibrosis and oral cancer. Clinical evidence suggests that the pathophysiology of the oral diseases is closely associated with immune deterioration. The objective of the present studies was to investigate the pro-apoptotic effect of areca nut extract (ANE) in lymphocytes. Exposure of naïve splenic lymphocytes to ANE significantly enhanced apoptosis in a time- and concentration-dependent manner. Results from Hoechst staining confirmed the morphological features characteristic of apoptosis in ANE-treated cells. ANE treatment induced the depolarization of mitochondrial membrane potential (Deltapsi(m)), which preceded the occurrence of apoptosis. In parallel with the disruption of Deltapsi(m), ANE induced the release of cytochrome c, and the activation of caspase-9, indicating the activation of the mitochondrion-dependent pathway. Moreover, an increased level in the intracellular reactive oxygen species was detected in ANE-treated lymphocytes undergoing apoptosis. ANE-mediated apoptosis, caspase-9 activation and ROS production, but not Deltapsi(m) depolarization, were partially but significantly attenuated in the presence of the antioxidant N-acetyl-L-cysteine (NAC). Collectively, these results demonstrated the pro-apoptotic effect of ANE in primary lymphocytes, which was mediated, at least in part, by the activation of the mitochondrion-dependent pathway and oxidative stress.