Barbiturate Anesthesia Research Articles

Midbrain sensitivity to auditory motion studied with dichotic sweeps of broadband noise

Many neurons in the central nucleus of the inferior colliculus (IC) show sensitivity to interaural time differences (ITDs), which is thought to be relayed from the brainstem. However, studies with interaural phase modulation of pure tones showed that IC neurons have a sensitivity to changes in ITD that is not present at the level of the brainstem. This sensitivity has been interpreted as a form of sensitivity to motion.A new type of stimulus is used here to study the sensitivity of IC neurons to dynamic changes in ITD, in which broad- or narrowband stimuli are swept through a range of ITDs with arbitrary start-ITD, end-ITD, speed, and direction. Extracellular recordings were obtained under barbiturate anesthesia in the cat. We applied the same analyses as previously introduced for the study of responses to tones.We find effects of motion which are similar to those described in response to interaural phase modulation of tones. The size of the effects strongly depended on the motion parameters but was overall smaller than reported for tones. We found that the effects of motion could largely be explained by the temporal response pattern of the neuron such as adaptation and build-up. Our data add to previous evidence questioning true coding of motion at the level of the IC.

Basil (Ocimum basilicum L.) and/or Celery (Apium graveolens L.) Leaves Aqueous Extracts Role in Opposition to Drinking Contaminated Water Induced Male Rats Urinary Stones and Renal Deteriorations

Aims: The current research was designed to explore the role of basil and/or celery leaves aqueous extracts against urinary stones (urolithiasis) and renal deteriorations induced by drinking water contaminated with ethylene glycol (EG) and ammonium chloride (AC) in male rats.
 Place and Duration of Study: The Medical Research Center of the Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt. The experiment duration was 35 days, 7 days for acclimatization followed by 28 days experimentation.
 Methodology: Fifty-five adult male Sprague-Dawley rats were classified randomly into 5 groups of ten animals each, except urolithiatic control group which contained 15 rats. Rats were treated as follow: Group I: healthy control group (HCG), rats drank distilled water and received a placebo 1 ml distilled water daily by intra-gastric tube ; Group II: urolithiatic control group (UCG), rats drank distilled water containing ( 0.75% EG and 1% AC ) and the access to water was ad libitum and received 1 ml distilled water daily by intra-gastric tube.; Group III : urolithiatic rats supplemented with aqueous basil extract(U+ABE), rats drank distilled water containing ( 0.75% EG and 1% AC) and the access to water was ad libitum and supplemented with (200mg/kg body weight) aqueous basil extract daily by intra-gastric tube.; Group IV: urolithiatic rats supplemented with aqueous celery extract(U+ACE), rats drank distilled water containing ( 0.75% EG and 1% AC) and the access to water was ad libitum and supplemented with (200mg/kg body weight) aqueous celery extract daily by intra-gastric tube. ; Group V: urolithiatic rats supplemented with aqueous basil and celery extract(U+ABE+ACE) , rats drank distilled water containing ( 0.75% EG and 1% AC) and the access to water was ad libitum and supplemented with (100mg/kg body weight) aqueous basil extract and (100mg/kg body weight) aqueous celery extract daily by intra-gastric tube. At the end of the study 28 days, 24 h urine samples were collected from each individual animal and then rats were sacrificed under sodium barbiturate anesthesia. Blood samples were collected from the hepatic portal vein, serum was separated for biochemical analyses. Kidney samples were separated for tissue homogenate preparation, urinary bladder and ureters were separated and opened to collect urinary calculi.
 Results: Research results documented that basil and celery aqueous extracts contain significant amount of active constituents including flavonoids and polyphenols. Drinking water contaminated with EG and AC caused significant decrease (p≤0.01) in urine volume, pH, urinary and renal magnesium levels with significant increase (p≤0.01) in urinary and renal calcium, phosphate and oxalate levels. It also caused significant increase in kidney function tests [serum creatinine, uric acid, urea, as well as cystatin C] levels .Also renal enzyme activities of [acidic phosphatase (ACP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP)] activities were significantly increased (p≤0.01) with significant decrease in renal lactate dehydrogenase (LDH) activity. Water contamination also induced renal mitochondrial dysfunction (decreased complex-1 activity), apoptosis (increased caspase-3 activity) in association with a state of renal oxidative stress [increased renal malondialdehyde (MDA) level related to decreased renal reduced glutathione (GSH)level and superoxide dismutase (SOD) activity].Inflammation [increased renal tumor necrosis factor- alpha (TNF- α) and interleukin 18 (IL-18)] with suppressed immune function [decreased serum immunoglobulin (IgG and IgM)] levels were observed in urolithiatic control group. As a result of biochemical changes resulted from EG and AM administration mineral precipitation and urinary stones formation was observed in urolithiatic control group. Oral administration of aqueous basil and /or celery extracts to urolithiatic rats improved urine analysis parameters, renal functions, renal enzymes activities and mitochondrial function. Aqueous extracts also counteracted renal oxidative stress, inflammation, suppressed immune response and urinary stones formation.
 Conclusion: Research results proved that aqueous basil and/or celery extracts counteracted and ameliorated urinary stones formation and renal deteriorations associated with drinking water contaminated with EG and AC due to their content of active constituents including flavonoids and polyphenols. The most significant improvements were recorded in the group supplemented with both extracts.

Spinal motoneurones are intrinsically more responsive in the adult G93A SOD1mouse model of amyotrophic lateral sclerosis.

Although in vitro recordings using neonatal preparations from mouse models of amyotrophic lateral sclerosis (ALS) suggest increased motoneurone excitability, in vivo recordings in adult ALS mouse models have been conflicting. In adult G93A SOD1models, spinal motoneurones have previously been shown to have deficits in repetitive firing, in contrast to the G127X SOD1mouse model. Our in vivo intracellular recordings in barbiturate-anaesthetized adult male G93A SOD1mice reveal that the incidence of failure to fire with current injection was equally low in control and ALS mice (∼2%). We show that failure to fire repetitively can be a consequence of experimental protocol and should not be used alone to classify otherwise normal motoneurones as hypo-excitable. Motoneurones in the G93A SOD1mice showed an increased response to inputs, with lower rheobase, higher input-output gains and increased activation of persistent inward currents. In vitro studies from transgenic amyotrophic lateral sclerosis models have suggested an increased excitability of spinal motoneurones. However, in vivo intracellular recordings from adult amyotrophic lateral sclerosis mice models have produced conflicting findings. Previous investigations using barbiturate anaesthetized G93A SOD1mice have suggested that some motoneurones are hypo-excitable, defined by deficits in repetitive firing. Our own previous recordings in G127X SOD1mice using different anaesthesia, however, showed no repetitive firing deficits and increased persistent inward currents at symptom onset. These discrepancies may be a result of differences between models, symptomatic stage, anaesthesia or technical differences. To investigate this, we repeated our original experiments, but in adult male G93A SOD1mice, at both presymptomatic and symptomatic stages, under barbiturate anaesthesia. In vivo intracellular recordings from antidromically identified spinal motoneurones revealed that the incidence of failure to fire with current injection was equally low in control and G93A SOD1mice (∼2%). Motoneurones in G93A SOD1mice fired significantly more spontaneous action potentials. Rheobase was significantly lower and the input resistance and input-output gain were significantly higher in both presymptomatic and symptomatic G93A SOD1mice. This was despite a significant increase in the duration of the post-spike after-hyperpolarization in both presymptomatic and symptomatic G93A SOD1mice. Finally, evidence of increased activation of persistent inward currents was seen in both presymptomatic and symptomatic G93A SOD1mice. Our results do not confirm previous reports of hypo-excitability of spinal motoneurones in the G93A SOD1mouse and demonstrate that the motoneurones show an increased response to inputs.

The anesthetic drug treatment of refractory and super-refractory status epilepticus around the world: Results from a global audit

Multinational and multicenter registries collecting cases of refractory and super-refractory status epilepticus help to understand what the current practice in the treatment of such conditions is and can improve the rational therapy. We prospectively collected 776 cases of refractory status epilepticus requiring continuous intravenous anesthetic drugs in an intensive care unit setting, through online questionnaires compiled by the treating physicians in 50 countries. Initiation of an intravenous anaesthetic drug was relatively delayed in middle-income compared with high-income countries. There were marked regional differences in the choice of initial intravenous anaesthetic drug. Generally, midazolam was the most commonly used initial anesthetic drug (56%), followed by propofol (35%), in Europe, propofol was preferred over midazolam. In addition to anesthesia, 26% of cases received some form of immunosuppression (with corticosteroids and/or intravenous immunoglobulin). In this observational study, outcome was not affected by choice or sequence of anesthetic drugs, and nor was the use of barbiturate anesthetics associated with poorer outcome. The proportion of patients responding to cycles of different anaesthetic drugs was high even after failure of the earlier anesthetics, but the neurological outcome progressively worsened the longer anaesthetic drugs were needed and the longer the status epilepticus continued. However, even in the 158 patients who required three or more different anaesthetic trials, 49% had seizure control on tapering the third anesthetic, and 20% had a good neurological outcome anywhere. For these reasons we believe that it is important to persist with therapy in patients who are intractable initially, especially as etiology, not the number of duration of anesthesia, is the primary determinant of prognosis.This article is part of the Special Issue “Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures"

Inhibitable photolabeling by neurosteroid diazirine analog in the β3-Subunit of human hetereopentameric type A GABA receptors

Pregnanolone and allopregnanolone-type ligands exert general anesthetic, anticonvulsant and anxiolytic effects due to their positive modulatory interactions with the GABAA receptors in the brain. Binding sites for these neurosteroids have been recently identified at subunit interfaces in the transmembrane domain (TMD) of homomeric β3 GABAA receptors using photoaffinity labeling techniques, and in homomeric chimeric receptors containing GABAA receptor α subunit TMDs by crystallography. Steroid binding sites have yet to be determined in human, heteromeric, functionally reconstituted, full-length, glycosylated GABAA receptors. Here, we report on the synthesis and pharmacological characterization of several photoaffinity analogs of pregnanolone and allopregnanolone, of which 21-[4-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzoxy]allopregnanolone (21-pTFDBzox-AP) was the most potent ligand. It is a partial positive modulator of the human α1β3 and α1β3γ2L GABAA receptors at sub-micromolar concentrations. [3H]21-pTFDBzox-AP photoincorporated in a pharmacologically specific manner into the α and β subunits of those receptors, with the β3 subunit photolabeled most efficiently. Importantly, photolabeling by [3H]21-pTFDBzox-AP was inhibited by the positive steroid modulators alphaxalone, pregnanolone and allopregnanolone, but not by inhibitory neurosteroid pregnenolone sulfate or by two potent general anesthetics and GABAAR positive allosteric modulators, etomidate and an anesthetic barbiturate. The latter two ligands bind to sites at subunit interfaces in the GABAAR that are different from those interacting with neurosteroids. 21-pTFDBzox-AP's potency and pharmacological specificity of photolabeling indicate its suitability for characterizing neurosteroid binding sites in native GABAA receptors.

Pentobarbital and other anesthetic agents induce opposite regulations of MAP kinases p-MEK and p-ERK, and upregulate p-FADD/FADD neuroplastic index in brain during hypnotic states in mice

Midazolam and ketamine-induced anesthesia were recently shown to induce a disruption of MEK/ERK sequential phosphorylation with parallel upregulation of p-FADD in the mouse brain. The present study was designed to assess whether other structurally diverse anesthetic agents (pentobarbital, ethanol, chloral hydrate, isoflurane) also impair brain p-MEK to p-ERK signal and increase p-FADD during the particular time course of ‘sleep’ in mice. Pentobarbital (50 mg/kg)-, ethanol (4000 mg/kg)-, chloral hydrate (400 mg/kg)-, and isoflurane (2% in O2)-induced anesthesia (range: 24–60 min) were associated with unaltered or increased p-MEK1/2 (up to +155%) and decreased p-ERK1/2 (up to −60%) contents, revealing disruption of MEK to ERK activation in mouse brain cortex. These anesthetic agents also upregulated cortical p-FADD (up to +110%), but not total FADD (moderately decreased), which resulted in increased neuroplastic/survival p-FADD/FADD ratios (up to +2.8 fold). The inhibition of pentobarbital metabolism with SKF525-A (a cytochrome P450 inhibitor) augmented barbiturate anesthesia (2.6 times) and induced a greater and sustained upregulation of p-MEK with p-ERK downregulation, as well as prolonged increases of p-FADD content and p-FADD/FADD ratio (effects lasting for more than 240 min). Pentobarbital also upregulated significantly the cortical contents of other markers of neuroplasticity such as the ERK inhibitor p-PEA-15 (up to +46%), the transcription factor NF-κB (up to +27%) and the synaptic density protein PSD-95 (up to +20%) during ‘sleep’. The results reveal a paradoxical stimulation of p-MEK without the concomitant (canonical) activation of p-ERK (e.g. with pentobarbital and isoflurane), for which various molecular mechanisms are discussed. The downregulation of brain p-ERK may participate in the manifestations of adverse effects displayed by most hypnotic/anesthetic agents in clinical use (e.g. amnesia).

The Subprimary Range of Firing Is Present in Both Cat and Mouse Spinal Motoneurons and Its Relationship to Force Development Is Similar for the Two Species.

In the motor system, force gradation is achieved by recruitment of motoneurons and rate modulation of their firing frequency. Classical experiments investigating the relationship between injected current to the soma during intracellular recording and the firing frequency (the I-f relation) in cat spinal motoneurons identified two clear ranges: a primary range and a secondary range. Recent work in mice, however, has identified an additional range proposed to be exclusive to rodents, the subprimary range (SPR), due to the presence of mixed mode oscillations of the membrane potential. Surprisingly, fully summated tetanic contractions occurred in mice during SPR frequencies. With the mouse now one of the most popular models to investigate motor control, it is crucial that such discrepancies between observations in mice and basic principles that have been widely accepted in larger animals are resolved. To do this, we have reinvestigated the I-f relation using ramp current injections in spinal motoneurons in both barbiturate-anesthetized and decerebrate (nonanesthetized) cats and mice. We demonstrate the presence of the SPR and mixed mode oscillations in both species and show that the SPR is enhanced by barbiturate anesthetics. Our measurements of the I-f relation in both cats and mice support the classical opinion that firing frequencies in the higher end of the primary range are necessary to obtain a full summation. By systematically varying the leg oil pool temperature (from 37°C to room temperature), we found that only at lower temperatures can maximal summation occur at SPR frequencies due to prolongation of individual muscle twitches.SIGNIFICANCE STATEMENT This work investigates recent revelations that mouse motoneurons behave in a fundamentally different way from motoneurons of larger animals with respect to the importance of rate modulation of motoneuron firing for force gradation. The current study systematically addresses the proposed discrepancies between mice and larger species (cats) and demonstrates that mouse motoneurons, in fact, use rate modulation as a mechanism of force modulation in a similar manner to the classical descriptions in larger animals.

A review of ketamine's role in ECT and non-ECT settings.

Up to 20% of depressed patients demonstrate treatment resistance to one or more adequate antidepressant trials, resulting in a disproportionately high burden of illness. Ketamine is a non-barbiturate, rapid-acting general anesthetic that has been increasingly studied in treatment resistant depression (TRD), typically at sub-anesthetic doses (0.5 mg/kg over 40 min by intravenous infusion). More recent data suggest that ketamine may improve response rates to electroconvulsive therapy (ECT) when used as an adjunct, but also as a sole agent. In the ECT setting, a dose of 0.8 mg/kg or greater of ketamine demonstrates improved reduction in depressive symptoms than lower doses; however, inconsistency and significant heterogeneity among studies exists. Clinical predictors of responses to ketamine have been suggested in terms of non-ECT settings. Ketamine does increase seizure duration in ECT, which is attenuated when concomitant barbiturate anesthetics are used. However, most studies are small, with considerable heterogeneity of the sample population and variance in dosing strategies of ketamine, ECT, and concomitant medications, and lack a placebo control, which limits interpretation. Psychotomimetic and cardiovascular adverse effects are reported with ketamine. Cardiovascular adverse effects are particularly relevant when ketamine is used in an ECT setting. Adverse effects may be mitigated with concurrent propofol; however, this adds complexity and cost compared to standard anesthesia. Long-term adverse effects are still unknown, but relevant, given recent class concerns for anesthetic and sedative agents.

Functional relationship between brainstem putative pain-facilitating neurons and spinal nociceptfive neurons during development of inflammation in rats

The so-called on- and off-cells of the rostral ventromedial medulla (RVM) send their axons to the spinal dorsal horn. Activation of on-cells precedes and coincides with a facilitation, and activation of off-cells coincides with an inhibition, of withdrawal reflexes elicited by noxious agents. Considerable evidence supports the notion that on- and off-cells modulate nocifensive reflexes during opioid and non-opioid action and also during normal circumstances and during peripheral neuropathy and inflammation. Yet it is unclear whether on- and off-cells act upon sensory spinal circuits that might lead to ascending projections and the experience of pain. Here, in deeply anesthetized rats we recorded single unit discharges from pairs of one on-like or off-like cell in RVM and a nociceptive neuron in the spinal dorsal horn with input from a hind paw. Both ongoing activity and responses to a calibrated noxious stimulus applied to the paw were documented during basal conditions and during development of paw inflammation. Probably due to the strong barbiturate anesthesia, off-like cells were depressed and did not yield interpretable results. However, we showed for the first time that during the increase in neuronal activity that results from paw inflammation the activity of spinal nociceptive neurons reflects the activity of their partner on-like cells in a highly correlated manner. This implies a tight relationship between spinal sensory and RVM modulatory functions that may underlie inflammation-induced hyperreflexia and clinically relevant hyperalgesia.

Contrasting Effects of the γ-Aminobutyric Acid Type A Receptor β3 Subunit N265M Mutation on Loss of Righting Reflexes Induced by Etomidate and the Novel Anesthetic Barbiturate R-mTFD-MPAB: Erratum.

Contrasting Effects of the γ-Aminobutyric Acid Type A Receptor β3 Subunit N265M Mutation on Loss of Righting Reflexes Induced by Etomidate and the Novel Anesthetic Barbiturate R-mTFD-MPAB: Erratum.

State-Dependent Modulation of Slow Wave Motifs towards Awakening.

Slow cortical waves that propagate across the cerebral cortex forming large-scale spatiotemporal propagation patterns are a hallmark of non-REM sleep and anesthesia, but also occur during resting wakefulness. To investigate how the spatial temporal properties of slow waves change with the depth of anesthetic, we optically imaged population voltage transients generated by mouse layer 2/3 pyramidal neurons across one or two cortical hemispheres dorsally with a genetically encoded voltage indicator (GEVI). From deep barbiturate anesthesia to light barbiturate sedation, depolarizing wave events recruiting at least 50% of the imaged cortical area consistently appeared as a conserved repertoire of distinct wave motifs. Toward awakening, the incidence of individual motifs changed systematically (the motif propagating from visual to motor areas increased while that from somatosensory to visual areas decreased) and both local and global cortical dynamics accelerated. These findings highlight that functional endogenous interactions between distant cortical areas are not only constrained by anatomical connectivity, but can also be modulated by the brain state.

Contrasting Effects of the γ-Aminobutyric Acid Type A Receptor β3 Subunit N265M Mutation on Loss of Righting Reflexes Induced by Etomidate and the Novel Anesthetic Barbiturate R-mTFD-MPAB: Erratum.

Contrasting Effects of the γ-Aminobutyric Acid Type A Receptor β3 Subunit N265M Mutation on Loss of Righting Reflexes Induced by Etomidate and the Novel Anesthetic Barbiturate R-mTFD-MPAB: Erratum.

Contrasting Effects of the γ-Aminobutyric Acid Type A Receptor β3 Subunit N265M Mutation on Loss of Righting Reflexes Induced by Etomidate and the Novel Anesthetic Barbiturate R-mTFD-MPAB.

Previous studies have shown that etomidate modulates γ-aminobutyric acid type A receptors by binding at the β-α subunit interface within the transmembrane domain of receptors that incorporate β2 or β3 subunits. Introducing an asparagine-to-methionine (N265M) mutation at position 265 of the β3 subunit, which sits within the etomidate-binding site, attenuates the hypnotic effect of etomidate in vivo. It was reported recently that the photoactivatable barbiturate R-mTFD-MPAB also acts on γ-aminobutyric acid type A receptors primarily by binding to a homologous site at the γ-β interface. Given this difference in drug-binding sites established by the in vitro experiments, we hypothesized that the β3-N265M-mutant mice would not be resistant to the anesthetic effects of R-mTFD-MPAB in vivo, whereas the same mutant mice would be resistant to the anesthetic effects of R-etomidate. We measured the effects of IV injection of etomidate and R-mTFD-MPAB on loss and recovery of righting reflex in wild-type mice and in mice carrying the β3-N265M mutation. Etomidate-induced hypnosis, as measured by the duration of loss of righting reflex, was attenuated in the N265M knock-in mice, confirming prior results. By contrast, recovery of balance and coordinated movement, as measured by the ability to maintain all 4 paws on the ground, was unaffected by the mutation. Neither hypnosis nor impairment of coordinated movement produced by the barbiturate R-mTFD-MPAB was affected by the mutation. The findings confirmed our hypothesis that mutating the etomidate-binding site would not alter the response to the barbiturate R-mTFD-MPAB. Furthermore, we confirmed previous studies indicating that etomidate-induced hypnosis is mediated in part by β3-containing receptors. We also extended previous findings by showing that etomidate-impaired balance and coordinated movement are not mediated by β3-containing receptors, thus implicating β2-containing receptors in this end point.

Anti-NMDA-R encephalitis: Should we consider extreme delta brush as electrical status epilepticus?

Seizures are common clinical manifestations in anti-N-methyl-d-aspartate receptor (anti-NMDA-R) encephalitis, among other neurological and psychiatric symptoms. During the course of the disease, some specific EEG patterns have been described: generalized rhythmic delta activity (GRDA) and extreme delta brush (EDB). In comatose patients, the association of these EEG abnormalities with subtle motor manifestations can suggest ongoing non-convulsive status epilepticus (NCSE). We report the case of a 28-year-old woman admitted for a clinical presentation typical of anti-NMDA-R encephalitis, which was confirmed by CSF analysis. She was rapidly intubated because of severe dysautonomia and disturbed consciousness. Clinical examination revealed subtle paroxysmal and intermittent myoclonic and tonic movements, correlated on video-EEG with GRDA and/or EDB. NCSE was then suspected, but electroclinical manifestations persisted despite many anti-epileptic drugs combinations, or reappeared when barbiturate anesthesia was decreased. In order to confirm or dismiss the diagnosis, intracranial pressure (ICP) and surface video-EEG monitoring were performed simultaneously and revealed no ICP increase, thus being strongly against a diagnosis of seizures. Sedation was progressively weaned, and clinical condition as well as EEG appearance progressively improved. Literature review revealed 11 similar cases, including 2 with focal NCSE. Of the nine other cases, NCSE diagnosis was finally excluded in 5 cases. NCSE diagnosis in association with anti-NMDA-R encephalitis is sometimes very difficult and its occurrence might be overestimated. Video-EEG is highly recommended and more invasive techniques may sometimes be necessary.

Thiamylal sodium increased inflammation and the proliferation of vascular smooth muscle cells.

BackgroundThiamylal sodium is a common anesthetic barbiturate prepared in alkaline solution for clinical use. There is no previously reported study on the effects of barbiturates on the inflammation and proliferation of vascular smooth muscle cells (VSMCs). Here, we examined the effects of clinical-grade thiamylal sodium solution (TSS) on the inflammation and proliferation of rat VSMCs.MethodsExpression levels of interleukin (IL)-1α, IL-1β, IL-6, and toll-like receptors in rat VSMCs were detected by quantitative reverse transcription-polymerase chain reaction and microarray analyses. The production of IL-6 by cultured VSMCs or ex vivo-cultured rat aortic segments was detected in supernatants by enzyme-linked immunosorbent assay. VSMC proliferation and viability were determined by the water-soluble tetrazolium-1 assay and trypan blue staining, respectively.ResultsTSS increased expression of IL-1α, IL-6, and TLR4 in VSMCs in a dose-dependent manner, and reduced IL-1β expression. Ex vivo TSS stimulation of rat aorta also increased IL-6. Low concentrations of TSS enhanced VSMC proliferation, while high concentrations reduced both cell proliferation and viability. Expression of IL-1 receptor antagonist, which regulates cell proliferation, was not increased by TSS stimulation. Exposure of cells to the TSS additive, sodium carbonate, resulted in significant upregulation of IL-1α and IL-6 mRNA levels, to a greater extent than TSS.ConclusionsTSS-induced proinflammatory cytokine production by VSMCs is caused by sodium carbonate. However, pure thiamylal sodium has an anti-inflammatory effect in VSMCs. TSS exposure to VSMCs may promote vascular inflammation, leading to the progression of atherosclerosis or in-stent restenosis, resulting in vessel bypass graft failure.

Repetitive intracerebroventricular (ICV) microinjection of orexina regulates sleep homeostasis and hastens recovery from deep barbiturate anesthesia induced sleep

Repetitive intracerebroventricular (ICV) microinjection of orexina regulates sleep homeostasis and hastens recovery from deep barbiturate anesthesia induced sleep

Positive and Negative Allosteric Modulation of an α1β3γ2 γ-Aminobutyric Acid Type A (GABAA) Receptor by Binding to a Site in the Transmembrane Domain at the γ+-β− Interface

In the process of developing safer general anesthetics, isomers of anesthetic ethers and barbiturates have been discovered that act as convulsants and inhibitors of γ-aminobutyric acid type A receptors (GABAARs) rather than potentiators. It is unknown whether these convulsants act as negative allosteric modulators by binding to the intersubunit anesthetic-binding sites in the GABAAR transmembrane domain (Chiara, D. C., Jayakar, S. S., Zhou, X., Zhang, X., Savechenkov, P. Y., Bruzik, K. S., Miller, K. W., and Cohen, J. B. (2013) J. Biol. Chem. 288, 19343-19357) or to known convulsant sites in the ion channel or extracellular domains. Here, we show that S-1-methyl-5-propyl-5-(m-trifluoromethyl-diazirynylphenyl) barbituric acid (S-mTFD-MPPB), a photoreactive analog of the convulsant barbiturate S-MPPB, inhibits α1β3γ2 but potentiates α1β3 GABAAR responses. In the α1β3γ2 GABAAR, S-mTFD-MPPB binds in the transmembrane domain with high affinity to the γ(+)-β(-) subunit interface site with negative energetic coupling to GABA binding in the extracellular domain at the β(+)-α(-) subunit interfaces. GABA inhibits S-[(3)H]mTFD-MPPB photolabeling of γ2Ser-280 (γM2-15') in this site. In contrast, within the same site GABA enhances photolabeling of β3Met-227 in βM1 by an anesthetic barbiturate, R-[(3)H]methyl-5-allyl-5-(m-trifluoromethyl-diazirynylphenyl)barbituric acid (mTFD-MPAB), which differs from S-mTFD-MPPB in structure only by chirality and two hydrogens (propyl versus allyl). S-mTFD-MPPB and R-mTFD-MPAB are predicted to bind in different orientations at the γ(+)-β(-) site, based upon the distance in GABAAR homology models between γ2Ser-280 and β3Met-227. These results provide an explanation for S-mTFD-MPPB inhibition of α1β3γ2 GABAAR function and provide a first demonstration that an intersubunit-binding site in the GABAAR transmembrane domain binds negative and positive allosteric modulators.

Evidence for TRPA1 involvement in central neural mechanisms in a rat model of dry eye

Dry eye (DE) disease is commonly associated with ocular surface inflammation, an unstable tear film and symptoms of irritation. However, little is known about the role of central neural mechanisms in DE. This study used a model for persistent aqueous tear deficiency, exorbital gland removal, to assess the effects of mustard oil (MO), a transient receptor potential ankyrin (TRPA1) agonist, on eyeblink and eyewipe behavior and Fos-like immunoreactivity (Fos-LI) in the trigeminal brainstem of male rats. Spontaneous tear secretion was reduced by about 50% and spontaneous eyeblinks were increased more than 100% in DE rats compared to sham rats. MO (0.02–0.2%) caused dose-related increases in eyeblink and forelimb eyewipe behavior in DE and sham rats. Exorbital gland removal alone was sufficient to increase Fos-LI at the ventrolateral pole of trigeminal interpolaris/caudalis (Vi/Vc) transition region, but not at more caudal regions of the trigeminal brainstem. Under barbiturate anesthesia ocular surface application of MO (2–20%) produced Fos-LI in the Vi/Vc transition, in the mid-portions of Vc and in the trigeminal caudalis/upper cervical spinal cord (Vc/C1) region that was significantly greater in DE rats than in sham controls. MO caused an increase in Fos-LI ipsilaterally in superficial laminae at the mid-Vc and Vc/C1 regions in a dose-dependent manner. Smaller, but significant, increases in Fos-LI also were seen in the contralateral Vc/C1 region in DE rats. TRPA1 protein levels in trigeminal ganglia from DE rats ipsilateral and contralateral to gland removal were similar.Persistent tear reduction enhanced the behavioral and trigeminal brainstem neural responses to ocular surface stimulation by MO. These results suggested that TRPA1 mechanisms play a significant role in the sensitization of ocular-responsive trigeminal brainstem neurons in this model for tear deficient DE.

Ginger-induced Ileal Motility is Modified by Stress: Sex Differences in Rats

Ginger is widely used as a spice and also an effective herbal medicine to treat gastrointestinal disorders. On the other hand, stress can induce various modulation of digestive motility. Here, we investigated ginger effects on stress-induced motility of the isolated ileum in male and female rats, in vitro. Rats (Wistar, SPF, 7-12 weeks of age, 148-393 g BW) were divided into Control (1G) and 3G groups. 3G stress (every day for 10 min) was loaded by centrifugal apparatus for 1, 3, 15 and 30 days. After the stress loading at each day, a 1 cm-long section of the ileum was isolated under barbiturate anesthesia and fixed to a Magnus-type chamber filled with Tyrode solution. Ileal movements were observed for 60 s following application of zingerone, which is also called vanillylacetone and a key component of the pungency of ginger (0.1-10 μM). Spontaneous motility movements with phasic and tonic patterns were observed in the ileum. The former was a peristalsis-like movement and the latter was a slow fluctuation of the baseline. Ginger induced enhanced effects on the rhythmic phasic motility in relation to amplitude. In the female, 3G gravity loading had no effects on the ginger-induced motility, however, suppressive effect of the ginger-induced phasic movements was clearly observed at day 15 in the male. The present study showed that gravity stress changed ginger-induced effects on phasic ileal motility in the male, but not in the female, indicating that sex differences were observed in the ginger effects modulated by stress loading.

Continuous infusion, general anesthesia and other intensive care treatment for uncontrolled status epilepticus.

To discuss the use of continuous infusions, general anesthesia, hypothermia, and ketogenic diet as treatment for uncontrolled status epilepticus in pediatric patients. Recent studies demonstrate that clinical practitioners have a hierarchy in approach in controlling refractory status epilepticus (RSE) and super-refractory status epilepticus in children. In the acute setting of RSE, midazolam achieves clinical seizure control at a mean of 41 min after starting an infusion. When midazolam has failed to control RSE, the evidence points to barbiturate anesthesia as the next frequently used option. When both midazolam and barbiturates have failed, use of isoflurane or ketamine anesthesia has been tried at a mean of 10 days after RSE onset, although the studies are largely anecdotal. Increasingly, the use of therapeutic hypothermia or ketogenic diet is described as a strategy for super-refractory status epilepticus, and better evidence for their use may become available from ongoing randomized studies. Uncontrolled episodes of status epilepticus require intensive care treatment and the literature describes a common pathway of care used by many. However, cases of truly refractory and super-refractory status epilepticus are seen infrequently at any given institution. One strategy to improve the quality of evidence is to develop prospective, national and multinational case registries to determine the range of presentations and causes, efficacy of treatments, and clinical outcomes.