Stress (Amsterdam, Netherlands)
Raff, H;Glaeser, BL;Szabo, A;Olsen, CM;Everson, CA;
PMID: 36856367 | DOI: 10.1080/10253890.2023.2185864
Hypothalamic-pituitary-adrenal (HPA) axis dynamics are disrupted by opioids and may be involved in substance abuse; this persists during withdrawal and abstinence and is associated with co-morbid sleep disruption leading to vulnerability to relapse. We hypothesized that chronic sleep restriction (SR) alters the HPA axis diurnal rhythm and the sexually dimorphic response to acute stressor during opioid abstinence. We developed a rat model to evaluate the effect of persistent sleep loss during opioid abstinence on HPA axis dynamics in male and female rats. Plasma ACTH and corticosterone were measured diurnally and in response to acute restraint stress in rats Before (control) compared to During subsequent opioid abstinence without or with SR. Abstinence, regardless of sleep state, led to an increase in plasma ACTH and corticosterone in the morning in males. There was a tendency for higher PM plasma ACTH during abstinence in SR males (p = 0.076). ACTH and corticosterone responses to restraint were reduced in male SR rats whereas there was a failure to achieve the post-restraint nadir in female SR rats. There was no effect of the treatments or interventions on adrenal weight normalized to body weight. SR resulted in a dramatic increase in hypothalamic PVN AVP mRNA and plasma copeptin in male but not female rats. This corresponded to the attenuation of the HPA axis stress response in SR males during opioid abstinence. We have identified a potentially unique, sexually dimorphic role for magnocellular vasopressin in the control of the HPA axis during opioid abstinence and sleep restriction.
Calafate, S;Özturan, G;Thrupp, N;Vanderlinden, J;Santa-Marinha, L;Morais-Ribeiro, R;Ruggiero, A;Bozic, I;Rusterholz, T;Lorente-Echeverría, B;Dias, M;Chen, WT;Fiers, M;Lu, A;Vlaeminck, I;Creemers, E;Craessaerts, K;Vandenbempt, J;van Boekholdt, L;Poovathingal, S;Davie, K;Thal, DR;Wierda, K;Oliveira, TG;Slutsky, I;Adamantidis, A;De Strooper, B;de Wit, J;
PMID: 37188873 | DOI: 10.1038/s41593-023-01325-4
Early Alzheimer's disease (AD) is associated with hippocampal hyperactivity and decreased sleep quality. Here we show that homeostatic mechanisms transiently counteract the increased excitatory drive to CA1 neurons in AppNL-G-F mice, but that this mechanism fails in older mice. Spatial transcriptomics analysis identifies Pmch as part of the adaptive response in AppNL-G-F mice. Pmch encodes melanin-concentrating hormone (MCH), which is produced in sleep-active lateral hypothalamic neurons that project to CA1 and modulate memory. We show that MCH downregulates synaptic transmission, modulates firing rate homeostasis in hippocampal neurons and reverses the increased excitatory drive to CA1 neurons in AppNL-G-F mice. AppNL-G-F mice spend less time in rapid eye movement (REM) sleep. AppNL-G-F mice and individuals with AD show progressive changes in morphology of CA1-projecting MCH axons. Our findings identify the MCH system as vulnerable in early AD and suggest that impaired MCH-system function contributes to aberrant excitatory drive and sleep defects, which can compromise hippocampus-dependent functions.
Karlen-Amarante, M;de Paula Leirão, I;Katayama, PL;Colombari, E;Bittencourt-Silva, PG;Menezes, MF;B Zoccal, D;
PMID: 36864609 | DOI: 10.1093/sleep/zsad055
Exposure to postnatal chronic intermittent hypoxia (pCIH), as experienced in sleep-disordered breathing, is a risk factor for developing cardiorespiratory diseases in adulthood. pCIH causes respiratory instability and motor dysfunction that persist until adult life. In this study, we investigated the impact of pCIH on the sympathetic control of arterial pressure in rats.Neonate male Holtzman rats (P0-1) were exposed to pCIH (6% O2 for 30 s, every 10 min, 8 h/day) during their first 10-15 days of life, while control animals were maintained under normoxia. In early adult life (P25-40), freely behaving pCIH animals (n=13) showed higher baseline arterial pressure levels linked to augmented sympathetic-mediated variability than control animals (n=12, P<0.05). Using decerebrated in situ preparations, we found that juvenile pCIH rats exhibited a two-fold increase in thoracic sympathetic nerve activity (n=14) and elevated firing frequency of ventromedullary presympathetic neurons (n=7) compared to control rats (n=6-7, P<0.05). This pCIH-induced sympathetic dysregulation was associated with increased HIF-1α (hypoxic inducible factor) mRNA expression in catecholaminergic pre-sympathetic neurons (n=5,P<0.05). At older age (P90-99), pCIH rats displayed higher arterial pressure levels and larger depressor responses to ganglionic blockade (n=6-8, P<0.05), confirming the sympathetic overactivity state.pCIH facilitates the vasoconstrictor sympathetic drive by mechanisms associated with enhanced firing activity and HIF-1α expression in ventromedullary pre-sympathetic neurons. This excessive sympathetic activity persists until adulthood resulting in high blood pressure levels and variability, which contribute to developing cardiovascular diseases.
Kroeger, D;Thundercliffe, J;Phung, A;De Luca, R;Geraci, C;Bragg, S;McCafferty, KJ;Bandaru, SS;Arrigoni, E;Scammell, TE;
PMID: 36170177 | DOI: 10.1093/sleep/zsac242
The pedunculopontine tegmental nucleus (PPT) is implicated in many brain functions, ranging from sleep/wake control and locomotion, to reward mechanisms and learning. The PPT contains cholinergic, GABAergic and glutamatergic neurons with extensive ascending and descending axonal projections. Glutamatergic PPT (PPT vGlut2) neurons are thought to promote wakefulness, but the mechanisms through which this occurs are unknown. In addition, some researchers propose that PPT vGlut2 neurons promote locomotion, yet even though the PPT is a target for deep brain stimulation in Parkinson's disease, the role of the PPT in locomotion is debated. We hypothesized that PPT vGluT2 neurons drive arousal and specific waking behaviors via certain projections and modulate locomotion via others.We mapped the axonal projections of PPT vGlut2 neurons using conditional anterograde tracing and then photostimulated PPT vGlut2 soma or their axon terminal fields across sleep/wake states and analyzed sleep/wake behavior, muscle activity, and locomotion in transgenic mice.We found that stimulation of PPT vGlut2 soma and their axon terminals rapidly triggered arousals from NREM sleep, especially with activation of terminals in the basal forebrain (BF) and lateral hypothalamus (LH). With photoactivation of PPT vGlut2 terminals in the BF and LH, this wakefulness was accompanied by locomotion and other active behaviors, but stimulation of PPT vGlut2 soma and terminals in the substantia nigra triggered only quiet wakefulness without locomotion.These findings demonstrate the importance of the PPT vGluT2 neurons in driving various aspects of arousal and show that heterogeneous brain nuclei, such as the PPT, can promote a variety of behaviors via distinct axonal projections.
Yao, Y;Barger, Z;Saffari Doost, M;Tso, CF;Darmohray, D;Silverman, D;Liu, D;Ma, C;Cetin, A;Yao, S;Zeng, H;Dan, Y;
PMID: 36170850 | DOI: 10.1016/j.neuron.2022.08.027
Sleep disturbances are strongly associated with cardiovascular diseases. Baroreflex, a basic cardiovascular regulation mechanism, is modulated by sleep-wake states. Here, we show that neurons at key stages of baroreflex pathways also promote sleep. Using activity-dependent genetic labeling, we tagged neurons in the nucleus of the solitary tract (NST) activated by blood pressure elevation and confirmed their barosensitivity with optrode recording and calcium imaging. Chemogenetic or optogenetic activation of these neurons promoted non-REM sleep in addition to decreasing blood pressure and heart rate. GABAergic neurons in the caudal ventrolateral medulla (CVLM)-a downstream target of the NST for vasomotor baroreflex-also promote non-REM sleep, partly by inhibiting the sympathoexcitatory and wake-promoting adrenergic neurons in the rostral ventrolateral medulla (RVLM). Cholinergic neurons in the nucleus ambiguous-a target of the NST for cardiac baroreflex-promoted non-REM sleep as well. Thus, key components of the cardiovascular baroreflex circuit are also integral to sleep-wake brain-state regulation.
Advanced science (Weinheim, Baden-Wurttemberg, Germany)
Yi, T;Wang, N;Huang, J;Wang, Y;Ren, S;Hu, Y;Xia, J;Liao, Y;Li, X;Luo, F;Ouyang, Q;Li, Y;Zheng, Z;Xiao, Q;Ren, R;Yao, Z;Tang, X;Wang, Y;Chen, X;He, C;Li, H;Hu, Z;
PMID: 36961096 | DOI: 10.1002/advs.202300189
Sevoflurane has been the most widely used inhaled anesthetics with a favorable recovery profile; however, the precise mechanisms underlying its anesthetic action are still not completely understood. Here the authors show that sevoflurane activates a cluster of urocortin 1 (UCN1+ )/cocaine- and amphetamine-regulated transcript (CART+ ) neurons in the midbrain involved in its anesthesia. Furthermore, growth hormone secretagogue receptor (GHSR) is highly enriched in sevoflurane-activated UCN1+ /CART+ cells and is necessary for sleep induction. Blockade of GHSR abolishes the excitatory effect of sevoflurane on UCN1+ /CART+ neurons and attenuates its anesthetic effect. Collectively, their data suggest that anesthetic action of sevoflurane necessitates the GHSR activation in midbrain UCN1+ /CART+ neurons, which provides a novel target including the nucleus and receptor in the field of anesthesia.
Teng, S;Zhen, F;Wang, L;Schalchli, JC;Simko, J;Chen, X;Jin, H;Makinson, CD;Peng, Y;
PMID: 35961989 | DOI: 10.1038/s41467-022-32461-3
Understanding the neural mechanisms underlying sleep state transitions is a fundamental goal of neurobiology and important for the development of new treatments for insomnia and other sleep disorders. Yet, brain circuits controlling this process remain poorly understood. Here we identify a population of sleep-active glutamatergic neurons in the ventrolateral medulla (VLM) that project to the preoptic area (POA), a prominent sleep-promoting region, in mice. Microendoscopic calcium imaging demonstrate that these VLM glutamatergic neurons display increased activity during the transitions from wakefulness to Non-Rapid Eye Movement (NREM) sleep. Chemogenetic silencing of POA-projecting VLM neurons suppresses NREM sleep, whereas chemogenetic activation of these neurons promotes NREM sleep. Moreover, we show that optogenetic activation of VLM glutamatergic neurons or their projections in the POA initiates NREM sleep in awake mice. Together, our findings uncover an excitatory brainstem-hypothalamic circuit that controls the wake-sleep transitions.
Zhou, H;Li, M;Zhao, R;Sun, L;Yang, G;
PMID: 36690899 | DOI: 10.1038/s41593-022-01250-y
Poor sleep is associated with the risk of developing chronic pain, but how sleep contributes to pain chronicity remains unclear. Here we show that following peripheral nerve injury, cholinergic neurons in the anterior nucleus basalis (aNB) of the basal forebrain are increasingly active during nonrapid eye movement (NREM) sleep in a mouse model of neuropathic pain. These neurons directly activate vasoactive intestinal polypeptide-expressing interneurons in the primary somatosensory cortex (S1), causing disinhibition of pyramidal neurons and allodynia. The hyperactivity of aNB neurons is caused by the increased inputs from the parabrachial nucleus (PB) driven by the injured peripheral afferents. Inhibition of this pathway during NREM sleep, but not wakefulness, corrects neuronal hyperactivation and alleviates pain. Our results reveal that the PB-aNB-S1 pathway during sleep is critical for the generation and maintenance of chronic pain. Inhibiting this pathway during the sleep phase could be important for treating neuropathic pain.
De Luca, R;Nardone, S;Grace, KP;Venner, A;Cristofolini, M;Bandaru, SS;Sohn, LT;Kong, D;Mochizuki, T;Viberti, B;Zhu, L;Zito, A;Scammell, TE;Saper, CB;Lowell, BB;Fuller, PM;Arrigoni, E;
PMID: 35851580 | DOI: 10.1038/s41467-022-31591-y
Humans and animals lacking orexin neurons exhibit daytime sleepiness, sleep attacks, and state instability. While the circuit basis by which orexin neurons contribute to consolidated wakefulness remains unclear, existing models posit that orexin neurons provide their wake-stabilizing influence by exerting excitatory tone on other brain arousal nodes. Here we show using in vivo optogenetics, in vitro optogenetic-based circuit mapping, and single-cell transcriptomics that orexin neurons also contribute to arousal maintenance through indirect inhibition of sleep-promoting neurons of the ventrolateral preoptic nucleus. Activation of this subcortical circuit rapidly drives wakefulness from sleep by differentially modulating the activity of ventrolateral preoptic neurons. We further identify and characterize a feedforward circuit through which orexin (and co-released glutamate) acts to indirectly target and inhibit sleep-promoting ventrolateral preoptic neurons to produce arousal. This revealed circuitry provides an alternate framework for understanding how orexin neurons contribute to the maintenance of consolidated wakefulness and stabilize behavioral state.