Caveolae as a target for Phoneutria nigriventer spider venom

An important transcellular transport mechanism in the blood-brain barrier (BBB) involves caveolae, which are specialized delta-shaped domains of the endothelial plasma membrane that are rich in cholesterol, glycosphingolipids and the scaffolding protein Caveolina-1 (Cav-1). In this work, we investigated whether the increase in endocytosis and transendothelial vesicular trafficking in rat cerebellum after blood-brain barrier breakdown (BBBb) induced by Phoneutria nigriventer spider venom (PNV) was mediated by caveolae. The expression of Cav-1, phosphorylated Cav-1 (pCav-1), dynamin-2 (Dyn2), Src kinase family (SKF) and matrix-metalloproteinase-9 (MMP9), proteins involved in caveolar dynamics and BBB opening, was investigated. Immunofluorescence, western blotting (WB) and transmission electron microscopy were used to assess changes at 1, 2, 5, 24 and 72 h post-venom. WB showed upregulation of Cav-1, Dyn2 and MMP9 at 1, 5 and 72 h (corresponding, respectively, to intervals when intoxication was most evident, when signs of recovery were present, and when no intoxication was detectable). In contrast, pCav-1 and SKF, which are essential for internalization and transport, decreased when Cav-1 and Dyn2, proteins essential for caveolar formation, were increased. Overall, these changes indicated that vesicular trafficking across the endothelium (high pCav/SKF levels) coincided with lower numbers of caveolae (Cav-1/Dyn2 downregulation) and lower expression of MMP9. Thus, the internalization (disassembly) of caveolae alternates with caveolar neoformation (assembly), resulting in changes in caveolar density in the endothelium membrane. These caveolar dynamics imply tensional mechanical stress that is important in triggering key signaling mechanisms. We conclude that PNV-induced breakdown of transcellular transport in the BBB is caused by an increase in caveolae-mediated endocytosis; this effect was correlated with the progression of temporal signs of envenoming. Caveolar dynamics are probably involved in shear stress and BBBb regulatory mechanisms in this experimental model.     

Supralethal poisoning by any of the classical nerve agents is effectively counteracted by procyclidine regimens in rats

A treatment regimen consisting of HI-6, levetiracetam, and procyclidine (termed the triple regimen) has previously been shown to work as a universal therapy against soman poisoning in rats, since it has capacities to function as both prophylactic and therapeutic measure. The purpose of the present study was to examine whether the triple regimen may have antidotal efficacy against intoxication by other classical nerve agents than soman. The treatment was given 1 and 5 min after exposure to a supralethal dose of nerve agents, and the results showed that the triple regimen successfully prevented or terminated seizures and preserved the lives of rats exposed to 5 × LD₅₀ of soman, sarin, cyclosarin, or VX, but solely 3 × LD₅₀ of tabun was managed by this regimen. To meet the particular antidotal requirements of tabun, the triple regimen was reinforced with obidoxime and was made to a quadruple regimen that effectively treated rats intoxicated by 5 × LD₅₀ of tabun. The rats recovered very well and the majority gained pre-exposure body weight within 7 days. Neuropathology was seen in all groups regardless of whether the rats seized or not. The most extensive damage was produced by sarin and cyclosarin. Differentiation between the nerve agents’ potency to cause lesions was probably seen because the efficacious treatments ensured survival of supralethal poisoning. A combination of 2 oximes and 2 anticonvulsants may be a prerequisite to counteract effectively high levels of poisoning by any classical nerve agent.     

Cutaneous silent periods are not affected by the antihistaminic drug cetirizine

ObjectiveNoxious digital nerve stimulation leads to transient suppression of the electromyographic activity in isometrically contracted hand muscles, known as the “cutaneous silent period” (CSP). To date, neurotransmitters potentially involved in mediating this electromyographic (EMG) suppression remain unknown. Anecdotal observation lead to the hypothesis that antihistaminic medication may counteract nociceptive EMG suppression, as CSPs in one male subject who was accustomed to CSP recordings were temporarily lost following ingestion of an antihistaminic drug for acute rhinitis. A second otherwise healthy male subject, who was on long-term cetirizine for allergic rhinitis, presented without clearly defined CSPs when volunteering for normal values.MethodsWe undertook a systematic study in five healthy subjects (including the one with temporarily lost CSPs) who underwent serial CSP testing after ingestion of 10 mg cetirizine. CSPs were elicited in thenar muscles following digit II and digit V stimulation (20 times sensory threshold, 100 sweeps rectified and averaged) before and 90, 180, and 360 min following intake of medication.ResultsCSP onset latency, CSP end latency and CSP duration, as well as the index of suppression did not change significantly following ingestion of 10 mg cetirizine. Repeat study in the subject with no clearly defined CSPs on long-term treatment revealed persistently absent CSPs after a 5-week withdrawal from cetirizine.ConclusionCSPs are not affected by therapeutic doses of the H1 antihistaminic cetirizine.SignificanceOur findings suggest that histamine plays no major role as a neurotransmitter of CSPs.     

The neuroprotective effect of diazoxide is mediated by mitochondrial ATP-dependent potassium channels in a rat model of acute subdural hematoma

Acute subdural hematoma (ASDH) results in neuronal death due to mitochondrial dysfunction and a subsequent cascade of apoptotic and necrotic events. We previously demonstrated that mitochondrial ATP-dependent potassium (mitoK_ATP) channels have a major role in cerebral ischemic preconditioning in vivo and in vitro. However, the role of the mitoK_ATP channel has not been investigated in the context of ASDH. Thus, the purpose of this study was to determine whether the mitoK_ATP channel mediates neuroprotection in a rat model of ASDH. Male Wistar rats were subjected to subdural infusion of 400 μL autologous venous blood. The rats were assigned to four experimental groups pretreated intraventricularly 15 minutes before ASDH with (1) vehicle (n = 10); (2) the mitoK_ATP channel agonist diazoxide (n = 9); (3) diazoxide plus the selective mitoK_ATP channel antagonist 5-hydroxydecanoate (5-HD) (n = 6); or (4) 5-HD alone (n = 6). Infarct volume was assessed at 4 days after ASDH. Brain edema formation was also measured. Pretreatment with diazoxide significantly reduced infarct volume and brain edema formation after ASDH. However, the effects of diazoxide were abolished by co-treatment with 5-HD. 5-HD alone increased infarct volume. These data suggest that the mitoK_ATP channel is an important mediator of the neuroprotective effects of cerebral preconditioning in a rat model of ASDH.     

Nerve growth factor increases the sensitivity to zinc toxicity and induces cell cycle arrest in PC12 cells

Zinc is a basic trace element that plays important roles in brain and, consequently, its homeostasis needs to be critically controlled. High zinc concentrations in the interneuron synaptic space may induce neuronal death through mechanisms still partially solved. Undifferentiated pheochromocytoma (PC12) cells have been used to study zinc toxicity. As these cells can be differentiated into neuronal-like cells, the results obtained from differentiated cultures are more useful to understand zinc toxicity in neurons. In this paper, we show by flow cytometry that nerve growth factor (NGF) induces PC12 cells differentiation characterized by cell cycle arrest in the G1/G0 phase, similarly to that observed in serum-deprived cultures. Zinc induces cell death in NGF-differentiated PC12 cultures with an EC₅₀ value of 143 ± 14 μM, which reveals a higher sensitivity with respect to undifferentiated PC12 cultures (EC₅₀, 308 ± 32 μM) and a similar response to that obtained in hippocampal neurons (134 ± 12 μM). Thus, the differentiation process appeared responsible for such increase in sensitivity. To further support this tenet, when the NGF differentiation was impaired in presence of 10 μM MK-801, a selective blocker of the N-methyl-d-aspartate (NMDA) receptor that plays a role in the differentiation process, the higher sensitivity to zinc was reverted to an EC₅₀ value of 241 ± 26 μM. Flow cytometry experiments showed that NGF-differentiated PC12 cells in presence of zinc were positive for propidium iodide but not for annexin-V labeling. These results, together with data from fluorescent labeling of nuclear fragmentation, caspase-3 activation, and reactive oxygen species generation, support the view that zinc toxicity in NGF-differentiated PC12 cells takes place mainly through a necrotic process.     

Phenotypic variability in a Spanish family with a Caveolin-3 mutation

We report a Spanish family affected from a late onset, hand-involved and autosomal dominant distal myopathy associated to Caveolin-3 mutation. Signs of muscle hyperexcitability and hyperckemia were observed in the youngest relatives but not motor symptoms.Patients and methodsNeurological examination was performed in all members of the family. Muscle biopsy sample was taken from the proband and DNA genomics was amplified for the two exons of Cav-3 by the polymerase chain reaction (PCR) in all the affected members and in three asymptomatic relatives.ResultsSigns of muscle hyperexcitability and hyperckemia were observed in the affected members from early ages. Cav-3 expression was greatly reduced in the sarcolemma of the proband's muscle. Genetic studies revealed a G → A transition at nucleotide position 80 in exon 1 of the Cav-3 gene (c.80G > A), generating a Arg → Gln change at codon 27 (p.R27Q) of the amino acid chain in heterozygous state, while no mutation was found in unaffected members.ConclusionsSigns of muscle hyperexcitability and hyperckemia at early ages may predict the development of a late onset autosomal dominant hand-involved myopathy associated to Cav-3 mutation in the family reported herein.     

Acute effects of pregabalin on the function and cellular distribution of CaV2.1 in HEK293t cells

We established a cell model to study the acute effects of pregabalin (PGB), a drug widely used in epilepsy and neuropathic pain, on voltage gated Ca_V2.1 (P/Q-type) calcium channels function and distribution at the membrane level. HEK293t cells were transfected with plasmids coding for all subunits of the Ca_V2.1 channel. We used a α1 fused to an eGFP tag to follow its distribution in time and at different experimental conditions.The expressed channel was functional as shown by the presence of barium-mediated, calcium currents of transfected cells measured by ‘whole-cell voltage-clamp’ recordings, showing a maximum current peak in the I–V curve at +20 mV. The GFP fluorescent signal was confined to the periphery of the cells. Incubation with 500 μM PGB, that binds α2δ subunits, for 30 min induced changes in localization of the fluorescent subunits as measured by fluorescent time lapse microscopy. These changes correlated with a reversible reduction of barium currents through Ca_V2.1 calcium channels under the same conditions. However, no changes in the cellular distribution of the subunits were visualized for cells either expressing another membrane associated protein or after exposure of the Ca_V2.1 channels to isoleucine, another α2δ ligand. Together these results show strong evidence for an acute effect of PGB on Ca_V2.1 calcium channels’ currents and distribution and suggest that internalization of Ca_V2.1 channels might be a mechanism of PGB action.     

Adult hippocampal neurogenesis is impaired by transient and moderate developmental thyroid hormone disruption

The hippocampus maintains a capacity for neurogenesis throughout life, a capacity that is reduced in models of adult onset hypothyroidism. The effects of developmental thyroid hormone (TH) insufficiency on neurogenesis in the adult hippocampus, however, has not been examined. Graded degrees of TH insufficiency were induced in pregnant rat dams by administration of 0, 3 or 10 ppm of 6-propylthiouracil (PTU) in drinking water from gestational day (GD) 6 until weaning. Body, brain, and hippocampal weight were reduced on postnatal day (PN) 14, 21, 78 and hippocampal volume was smaller at the 10 but not 3 ppm dose level. A second experiment examined adult hippocampal neurogenesis following developmental or adult onset hypothyroidism. Two male offspring from 0 and 3 ppm exposed dams were either maintained on control water or exposed to 3 ppm PTU to create 4 distinct treatment conditions (Control-Control; Control-PTU, PTU-Control, PTU-PTU) based on developmental and adult exposures. Beginning on the 28th day of adult exposure to 0 or 3 ppm PTU, bromodeoxyuridine (BrdU, 50 mg/kg, ip) was administered twice daily for 5 days, and one male from each treatment was sacrificed 24 h and 28 days after the last BrdU dose and brains processed for immunohistochemistry. Although no volume changes were seen in the hippocampus of the neonate at 3 ppm, thinning of the granule cell layer emerged in adulthood. Developmental TH insufficiency produced a reduction in newly born cells, reducing BrdU + ve cells at 1 with no further reduction at 28-days post-BrdU. Similar findings were obtained using the proliferative cell marker Ki67. Neuronal differentiations was also altered with fewer doublecortin (Dcx) expressing cells and a higher proportion of immature Dcx phenotypes seen after developmental but not adult TH insufficiency. An impaired capacity for neurogenesis may contribute to impairments in synaptic plasticity and cognitive deficits previously reported by our laboratory and others following moderate degrees of developmental TH insufficiency induced by this PTU model.     

The effect of childhood obstructive sleep apnea on ambulatory blood pressure is modulated by the distribution of respiratory events during rapid eye movement and nonrapid eye movement sleep

ObjectiveWe aimed to investigate if different childhood obstructive sleep apnea (OSA) subtypes, namely rapid eye movement (REM)-related, nonrapid eye movement (NREM)-related and stage-independent OSA would exert different effects on ambulatory blood pressure (ABP).MethodsData from our previous school-based cross-sectional study were reanalyzed. Subjects who had an obstructive apnea–hypopnea index (OAHI) between 1 and 10 events per hour and a total REM sleep duration of >30 min were included in our analysis. REM-related and NREM-related OSA were defined as a ratio of OAHI in REM sleep (OAHI_REM) to OAHI in NREM sleep (OAHI_NREM) of >2 and <0.5, respectively. The others were classified as stage-independent OSA.ResultsA total of 162 subjects were included in the analysis. In the mild OSA (OAHI, 1–5 events/h) subgroup, no significant differences in any ABP parameters were found between OSA subtypes. On the other hand, in subjects with moderate OSA (OAHI, 5–10 events/h), the REM-related OSA subtype had a significantly lower daytime systolic blood pressure (SBP) z score (−0.13 ± 0.90 cf 1.15 ± 0.67; P = .012) and nighttime SBP z score (0.29 ± 1.06 cf 1.48 ± 0.88, P = .039) than the stage-independent OSA subtype. Linear regression analyses revealed that OAHI_NREM but not OAHI_REM was significantly associated with both daytime (P = .008) and nighttime SBP (P = .042) after controlling for age, gender, and body size.ConclusionChildren with obstructive events mainly in REM sleep may have less cardiovascular complications than those with stage-independent OSA.     

Mechanisms operated by endothelin ETA and ETB receptors in the trigeminal ganglion contribute to orofacial thermal hyperalgesia induced by infraorbital nerve constriction in rats

Endothelins, acting through specific endothelin ET_A and/or ET_B receptors, participate in nociceptive processing in models of cancer, inflammatory and neuropathic pain. The present study investigated which cell types express endothelin receptors in the trigeminal ganglion, and the contribution of mechanisms mediated by endothelin ET_A and ET_B receptors to orofacial heat hyperalgesia induced by unilateral constriction of the infraorbital nerve (CION). Both receptor types were identified by immunohistochemistry in the trigeminal ganglion, ET_A receptors on small-sized non-myelinated and myelinated A-fibers and ET_B receptors on both satellite glial cells and small-sized non-myelinated neuronal cells. CION promoted ipsilateral orofacial heat hyperalgesia which lasted from Day 2 until Day 10 after surgery. Ongoing CION-induced heat hyperalgesia (on Day 4) was reduced transiently, but significantly, by systemic or local treatment with antagonists of endothelin ET_A receptors (atrasentan, 10 mg/kg, i.v.; or BQ-123, 10 nmol/lip), endothelin ET_B receptors (A-192621, 20 mg/kg, i.v.; or BQ-788, 10 nmol/ lip), or of both ET_A/ET_B receptors (bosentan, 10 mg/kg, i.v.; or BQ-123 plus BQ-788, each at 10 nmol/lip). On the other hand, CION-induced heat hyperalgesia was transiently abolished over the first 90 min following i.p. injection of morphine hydrochloride (2.5 mg/kg), but fully resistant to reversal by indomethacin (4 mg/kg, i.p.) or celecoxib (10 mg/kg, i.p.). Thus, heat hyperalgesia induced by CION is maintained, in part, by peripheral signaling mechanisms operated by ET_A and ET_B receptors. Endothelin receptors might represent promising therapeutic targets for the control of trigeminal neuropathic pain.     

Neutrophil/lymphocyte ratio is associated with thromboembolic stroke in patients with non-valvular atrial fibrillation

BackgroundNeutrophil/lymphocyte ratio (NLR) has been associated with poor outcomes in patients with cardiovascular diseases. However, little is known about the role of NLR in patients with thromboembolic stroke due to atrial fibrillation (AF). We aimed to compare the NLR ratios between non-valvular AF patients with or without thromboembolic stroke.MethodsA total of 126 non-valvular AF patients with or without stroke were included in the study; 126 consecutive patients (52 males and 74 females), mean age, 70 ± 10.2 years old. No patient had a recent history of an acute infection or an inflammatory disease. Baseline NLR was measured by dividing neutrophil count to lymphocyte count. WBC count > 12.000 cells per μL or < 4.000 cells per μL and high body temperature > 38 º are excluded from the study.ResultsMean NLR was significantly higher among persons with stroke compared to individuals without a stroke (5.6 ± 3.4 vs. 3.1 ± 2.1, p = 0.001). There were no significant differences in RDW levels between the two groups (p > 0.05). HAS-BLED and CHADS₂ scores were significantly higher in the stroke group.ConclusionHigher NLR, an emerging marker of inflammation, is associated with thromboembolic stroke in non-valvular AF patients.     

Early screening and identification of psychological comorbidities in pediatric epilepsy is necessary

Youth with epilepsy often have co-occurring psychological symptoms that are due to underlying brain pathology, seizures, and/or antiepileptic drug side effects. The primary study aim was to compare the psychological comorbidities of youth with new-onset epilepsy versus chronic epilepsy. Primary caregivers of youth with either new-onset (n = 82; M_age = 9.9 ± 2.9) or chronic epilepsy (n = 76; M_age = 12.8 ± 3.3) completed the Behavioral Assessment Scale for Children—2nd Edition. Compared to those with new-onset epilepsy, the chronic group had significantly higher depressive and withdrawal symptoms, as well as lower activities of daily living. A higher proportion of youth with chronic epilepsy exhibited at-risk/clinically elevated depressive symptoms and difficulties with activities of daily living compared to the new-onset group. Proactive screening in youth with epilepsy to ensure timely identification of psychological symptoms and to guide early psychological intervention is warranted.     

Influence of limb temperature on cutaneous silent periods

ObjectiveThe cutaneous silent period (CSP) is a spinal inhibitory reflex mediated by small-diameter afferents (A-delta fibers) and large-diameter efferents (alpha motoneurons). The effect of limb temperature on CSPs has so far not been assessed.MethodsIn 27 healthy volunteers (11 males; age 22–58 years) we recorded median nerve motor and sensory action potentials, median nerve F-wave and CSPs induced by noxious digit II stimulation in thenar muscles in a baseline condition at room temperature, and after randomly submersing the forearm in 42 °C warm or 15 °C cold water for 20 min each.ResultsIn cold limbs, distal and proximal motor and sensory latencies as well as F-wave latencies were prolonged. Motor and sensory nerve conduction velocities were reduced. Compound motor and sensory nerve action potential amplitudes did not differ significantly from baseline. CSP onset and end latencies were more delayed than distal and proximal median nerve motor and sensory latencies, whereas CSP duration was not affected. In warm limbs, opposite but smaller changes were seen in nerve conduction studies and CSPs.ConclusionThe observed CSP shift “en bloc” towards longer latencies without affecting CSP duration during limb cooling concurs with slower conduction velocity in both afferent and efferent fibers. Disparate conduction slowing in afferents and efferents, however, suggests that nociceptive EMG suppression is mediated by fibers of different size in the afferent than in the efferent arm, indirectly supporting the contribution of A-delta fibers as the main afferent input.SignificanceLimb temperature should be taken into account when testing CSPs in the clinical setting, as different limb temperatures affect CSP latencies more than large-diameter fiber conduction function.     

Suppression of ATP-induced excitability in rat small-diameter trigeminal ganglion neurons by activation of GABAB receptor

The aim of the present study was to investigate whether a GABA_B receptor agonist could modulate ATP-activated neuronal excitability of nociceptive TRG neurons using perforated whole-cell patch-clamp and immunohistochemical techniques. Immunohistochemical analysis revealed that 86% of P₂X₃ receptor-immunoreactive, small-diameter TRG neurons co-expressed GABA_B receptor. Under voltage-clamp conditions (V_h = −60 mV), application of ATP activated the inward current in acutely isolated rat TRG neurons in a dose-dependent manner (10–50 μM) and this current could be blocked by pyridoxal-phosphate-6-azophenyl-27,47-disulfonic acid (PPADS) (10 μM), a selective P₂ purinoreceptor antagonist. The peak amplitude of ATP-activated currents was significantly inhibited after application of GABA_B receptor agonist, baclofen (10–50 μM), in a concentration-dependent and reversible manner. The baclofen-induced inhibition of ATP-activated current was abolished by co-application of 3-amino-2 (4-chlorophenyl)-2hydroxypropysufonic acid) saclofen, a GABA_B receptor antagonist (50 μM). Under current-clamp conditions, application of 20 μM ATP significantly depolarized the membrane potential resulting in increased mean action potential frequencies, and these ATP-induced effects were significantly inhibited by baclofen and these effects were antagonized by co-application of saclofen. Together, the results suggested that GABA_B receptor activation could inhibit the ATP-induced excitability of small-diameter TRG neurons activated through the P₂X₃ receptor. Thus, the interaction between P₂X₃ and GABA_B receptors of small-diameter TRG neuronal cell bodies is a potential therapeutic target for the treatment of trigeminal nociception.     

Dynamic cerebral autoregulation is compromised in ischaemic stroke of undetermined aetiology only in the non-affected hemisphere

Background and purposeTo assess dynamic cerebral autoregulation (CA) in patients with acute ischaemic stroke of undetermined aetiology, within 72 h of stroke onset.Materials and methodsIn 6 patients with ischaemic stroke of undetermined aetiology (aged 66 ± 9 years, National Institutes of Health Stroke Scale [NIHSS] score on admission: 4.0, range: 4–11), selected based on screening of 118 consecutive ischaemic stroke patients and in 14 volunteers (aged 62 ± 10 years), we continuously monitored RR intervals (RRI), mean arterial pressure (MAP) by means of photoplethysmography, mean cerebral blood flow velocity (CBFV) using transcranial Doppler ultrasonography, end-tidal CO₂ (ETCO₂) and respiration during 2-min deep breathing paced at 6 min⁻¹ (0.1 Hz). To assess CA, we evaluated the impact of breathing-induced MAP oscillations on fluctuations of CBFV in the hemispheres with stroke, the non-involved hemispheres and randomly selected hemispheres of controls by applying cross-spectral analysis and calculating coherence, transfer function gain (CBFV–MAP gain) and phase shift angle between the two oscillating signals.ResultsPhase shift angle between MAP and CBFV oscillations showed values >0 and was significantly reduced in the hemispheres without stroke as compared to controls (0.39 ± 0.95 vs. −1.59 ± 0.33 rad, p = 0.015), whereas in the hemispheres with stroke, phase shift angle did not differ significantly from that observed in the control hemispheres. Clinical status of stroke patients significantly improved at discharge from the hospital (NIHSS: 2.0, range: 1–8, p = 0.028).ConclusionsDuring the first days of ischaemic stroke of undetermined aetiology, dynamic cerebral autoregulation is compromised in the non-affected hemisphere, but not in the hemisphere with ischaemic lesion.     

Generation of hydrogen peroxide mediates hanging death-induced neuronal cell apoptosis in the dentate gyrus of the rat brain

Present study was aimed to find out whether hanging death (HD) induces generation of reactive oxygen species (ROS) and neuronal cell apoptosis in the dentate gyrus (DG) region of rat brain. Permanent global brain ischemia was generated by HD in experimental rats and the brain was isolated after 0, 1, 2, 3, 4, 5, 6, 9, 12 and 24 h post- HD and cervical dislocation (CD). The histology, hydrogen peroxide (H₂O₂) concentration, catalase, caspase-9 and caspase-3 activities and DNA fragmentation were analyzed in neuronal cells of DG region of the brain. Permanent global brain ischemia generated due to HD induced generation of H₂O₂ as well as catalase activity. The increased level of H₂O₂ was associated with the increased caspase-9 and caspase-3 activities. The increased caspase-3 activity induced neuronal cell apoptosis during early period (0–9 h) of HD as compare to CD group. The neuronal cells necrosis was observed only 12 h post-HD, while CD induced necrosis as early as 3 h post-CD and the histoarchitecture of DG region was gradually disrupted after 6 h of CD. In conclusion, data of the present study suggest that the permanent global brain ischemia induces neuronal cell apoptosis during early period of HD through ROS-mediated pathway, while CD induces neuronal cell necrosis and disruption of the histoarchitecture of the DG region. Thus, neuronal cell apoptosis may be used to develop a cellular marker to find out the exact timing of HD.     

A population of atypical CD56−CD16+ natural killer cells is expanded in PTSD and is associated with symptom severity

IntroductionPost-traumatic stress disorder (PTSD) has been associated with immune disturbances, including a higher incidence of infections and autoimmune diseases as well as a net pro-inflammatory state. Natural killer (NK) cells, a key component of the innate immune system, have been less well-studied in PTSD despite their importance in immunity.MethodsWe studied two independent samples of combat-exposed male war veterans with or without PTSD, the first (“Discovery Sample”) to generate hypotheses, and the second (“Validation Sample”) to replicate the findings. The Discovery Sample was comprised of 42 PTSD subjects and 42 controls. The Validation Sample was comprised of 25 PTSD subjects and 30 controls. Participants had fasting, morning blood samples collected for examination of the frequency of NK cell subsets, determined by flow cytometry. The current and lifetime Clinician Administered PTSD Scale (CAPS) was used to assess symptom severity. Statistical analyses were adjusted for age and BMI.ResultsPTSD subjects compared to controls had (i) a significantly higher relative frequency of atypical CD56⁻CD16⁺ NK cells in the Discovery Sample (p = 0.027), which was replicated in the Validation Sample (p = 0.004) and the combined sample (p < 0.001), and (ii) a non-significantly lower relative frequency of CD56^brightCD16⁻ NK cells in the two samples (p = 0.082; p = 0.118), which became statistically significant in the combined sample (p = 0.020). Further, within subjects with PTSD of both samples, the relative frequency of atypical CD56⁻CD16⁺ NK cells was near significantly positively correlated with lifetime PTSD severity (p = 0.074).DiscussionThis study is the first to characterize NK cell subsets in individuals with PTSD. The results suggest that combat-exposed men with PTSD exhibit an aberrant profile of NK cells with significantly higher frequencies of an atypical population of CD56⁻CD16⁺ cells and possibly lower frequencies of the functional CD56^brightCD16⁻ NK cell subsets. Higher proportions of dysfunctional CD56⁻CD16⁺ cells have been reported in certain chronic viral infections and in senescent individuals. It is possible that this could contribute to immune dysfunctions and prematurely senescent phenotypes seen in PTSD.     

The potential role of serotonergic mechanisms in the spinal oxytocin-induced antinociception

The role of oxytocin (OXT) in pain modulation has been suggested. Indeed, hypothalamic paraventricular nuclei (PVN) electrical stimuli reduce the nociceptive neuronal activity (i.e., neuronal discharge associated with activation of Aδ- and C-fibers) of the spinal dorsal horn wide dynamic range (WDR) cells and nociceptive behavior. Furthermore, raphe magnus nuclei lesion reduces the PVN-induced antinociception, suggesting a functional interaction between the OXT and the serotoninergic system. The present study investigated in Wistar rats the potential role of spinal serotonergic mechanisms in the OXT- and PVN-induced antinociception. In long-term secondary mechanical allodynia and hyperalgesia induced by formalin or extracellular unitary recordings of the WDR cells we evaluated the role of 5-hydroxytryptamine (5-HT) effect on the OXT-induced antinociception. All drugs were given intrathecally (i.t.). OXT (1 × 10^− 5–1 × 10^− 4 nmol) or 5-HT (1 × 10^− 3–1 × 10^− 1 nmol) prevented the formalin-induced sensitization, an effect mimicked by PVN stimulation. Moreover, administration of OXT (1 × 10^− 5 nmol) plus 5-HT (1 × 10^− 3 nmol) at ineffective doses, produced antinociception. This effect was antagonized by: (i) d(CH₂)₅[Tyr(Me)²,Thr⁴,Tyr-NH₂⁹]OVT (oxytocin receptor antagonist; 2 × 10^− 2 nmol); or (ii) methiothepin (a non-specific 5-HT_1/2/5/6/7 receptor antagonist; 80 nmol). Similar results were obtained with PVN stimulation plus 5-HT (5 × 10^− 5 nmol). In WDR cell recordings, the PVN-induced antinociception was enhanced by i.t. 5-HT and partly blocked when the spinal cord was pre-treated with methiothepin (80 nmol). Taken together, these results suggest that serotonergic mechanisms at the spinal cord level are partly involved in the OXT-induced antinociception.     

Effects of ramelteon on insomnia symptoms induced by rapid,eastward travel

ObjectiveRamelteon, an MT₁/MT₂ melatonin receptor agonist, was evaluated for its ability to reduce sleep-onset difficulties associated with eastward jet travel.MethodsHealthy adults (n = 110) with a history of jet lag sleep disturbances were flown eastward across five time zones from Hawaii to the east coast of the US. Ramelteon 1, 4, or 8 mg or placebo was administered 5 min before bedtime (local time) for four nights. Sleep parameters were measured using polysomnography (PSG) on Nights 2, 3, and 4. Next-day residual effects were assessed using psychomotor and memory function tests.ResultsCompared to placebo, there was a significant decrease in mean latency to persistent sleep (LPS) on Nights 2–4 with ramelteon 1 mg (?10.64 min, P = 0.030). No consistent significant differences were observed with ramelteon vs. placebo on measures of next-day residual effects except on Day 4 where participants in all ramelteon groups performed significantly worse on the immediate memory recall test compared with placebo (P ? 0.05). The incidence of adverse events was similar for ramelteon and placebo.ConclusionAfter a 5-h phase advance due to eastward jet travel, ramelteon 1 mg taken before bedtime for four nights reduced mean LPS relative to placebo in healthy adults.