Development and characterization of novel fast-dissolving pentobarbital suppositories for pediatric procedural sedation and comparison with lipophilic formulations.

For pediatric radiological procedures (RP), pentobarbital sodium (PNa) can be used orally or rectally to replace intravenous anesthesia. Since no commercial PNa suppositories exist, they must be prepared by compounding pharmacies. This study aims to develop fast-dissolving PNa suppositories for fast pharmacological activity during RP. We prepared gelatin (G), gelatin/polyethylene glycol 4000 (GP), and polyethylene glycol 4000 (P) suppositories, with and without pH adjustment, and assessed their dosage uniformity (DU), softening time, rupture resistance, and in-vitro dissolution. An optimal formulation was selected, and PNa release was compared to that of fat-based suppositories using dissolution tests. Additionally, the quality control process (analytical performance, safety/eco-friendliness and productivity/practical effectiveness) of these formulas were compared using a RGB method. All hydrophilic formulas (HF) met the DU requirement (AV < 8 %) except for P (AV 15.62 ± 4 %). pH adjustment enhanced G and GP suppositories resistance to 2.2 ± 0.2 kg and 2.0 ± 0.3 kg, respectively, and allowed 100 % release of PNa in under 10 min. In contrast, lipophilic formulas released less than 80 % of PNa at best after 120 min. These results show the biopharmaceutical suitability of HF for RP compared to lipophilic ones, but a pharmacokinetic study is needed to confirm data.

Transmucosal administration of pentobarbital and phenytoin solution induces euthanasia in bearded dragons (Pogona vitticeps).

OBJECTIVE: To assess the efficacy of transmucosal euthanasia solution to induce euthanasia. ANIMALS: 6 bearded dragons (Pogona vitticeps). METHODS: An initial dose of euthanasia solution containing pentobarbital and phenytoin sodium was administered transmucosally in conscious lizards (100 mg/kg pentobarbital dose), followed by a second dose 20 minutes later (400 mg/kg pentobarbital dose). The presence of movement, leakage of euthanasia solution, behaviors consistent with oral irritation, respiratory rate, heart rate, palpebral and corneal reflex, and response to noxious stimuli were recorded until death, confirmed by the absence of Doppler cardiac flow and cardiac electrical activity. The time to loss of all parameters was calculated. Postmortem evaluation allowed for histopathologic evaluation of the oral cavity and gastrointestinal tract to detect potential mucosal damage from the alkaline euthanasia solution. RESULTS: The median time to death was 300 minutes (range, 300 to 360 minutes), median time to respiratory arrest was 30 minutes (range, 30 to 50 minutes), and median time to loss of deep pain response was 30 minutes (range, 20 to 50 minutes). Signs consistent with oral irritation occurred in 4 of 6 (66.7%) lizards, including 2 lizards that exhibited whole-body spasms after euthanasia solution administration. Histopathologic changes indicating peracute mucosal ulceration, suspected to be from caustic causes, were identified in 1 (1/6 [16.7%]) lizard. CLINICAL RELEVANCE: Transmucosal euthanasia solution administration resulted in clinical euthanasia within 6 hours. This method should be utilized only after premedication with analgesic and/or anesthetic medications due to the potential for acute mucosal ulceration and behaviors that may be distressing in client-owned animals.

Discriminative stimulus properties of two training doses of gabapentin in rats: Substitution by pregabalin, diazepam, and pentobarbital.

Gabapentin is used for the treatment of many conditions, including seizures, pain, and anxiety. Increasing reports of nonprescribed use suggest that gabapentin may elicit positive subjective effects. The present study was conducted to examine the subjective effects of gabapentin using rats trained to discriminate either a 30.0 mg/kg or 300.0 mg/kg dose of gabapentin versus vehicle on a two-choice drug discrimination task. Both doses of gabapentin were established as discriminative stimuli, and the 300.0 mg/kg dose was more readily established compared to the 30.0 mg/kg dose. Full substitution (> 80% gabapentin-lever responding) occurred by the training drug and by the gabapentinoid compound pregabalin. Partial substitution (> 20% gabapentin-lever responding) was shown by the opioid compounds morphine and fentanyl, and dose combinations of the opioid receptor antagonist naltrexone with the gabapentin training doses reduced the percentage of gabapentin-lever responding to below 80%. Partial substitution for both training doses of gabapentin occurred with the cannabinoid Δ9-tetrahydrocannabinol. The barbiturate compound pentobarbital and the benzodiazepine compound diazepam were only tested for substitution for the 300.0 mg/kg dose of gabapentin and these compounds produced full substitution. These findings demonstrate that gabapentin establishes a robust discriminative cue and exhibits stimulus effects closely similar to pregabalin, pentobarbital, and diazepam. Since pregabalin, pentobarbital, and diazepam carry a risk of problematic use and are classified as controlled substances, further evaluations of gabapentin's risks in this regard are warranted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Leonurine Preconditioning Attenuates Ischemic Acute Kidney Injury in Rats by Promoting Nrf2 Nuclear Translocation and Suppressing TLR4/NF-κB Pathway.

Despite the precise mechanisms for renal ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) are poorly understood, nuclear factor erythroid 2 related factor 2 (Nrf2) and Toll-like receptor 4 (TLR4) pathways were considered as the important targets. Leonurine (LEO) is a special alkaloid extracted from Chinese motherwort (Leonurus japonicus Houtt), which has an anti-inflammatory effect and reduces oxidative stress. We conducted the study to explore the efficacy of LEO against I/R-induced AKI in rats and further investigated the underlying mechanisms. Ischemic renal injury was induced by temporary vascular clamping for 45 min. We have measured the levels of inflammation-related biomarkers and antioxidative stress markers. Next, Western blot analysis and Real-time PCR were performed to analyze whether the Nrf2 and TLR4/nuclear factor-kappaB (NF-κB) pathways were involved in this process. We found that LEO pretreatment remarkably decreased serum creatinine and blood urea nitrogen (BUN) in I/R rats and attenuated acute tubular damage. In addition, LEO markedly increased the expression of antioxidant proteins and decreased the levels of inflammatory factors. Further study revealed that LEO promoted Nrf2 into the nucleus, promoted the expression of heme oxygenase-1 (HO-1) and quinone oxidoreductase 1 (NQO-1), and suppressed the TLR4/NF-κB signal pathway in kidney tissues of ischemic AKI rats. The study reveals that LEO has a protective effect to prevent ischemic AKI through activation of Nrf2 nuclear translocation resisting oxidative stress injury and inhibition of the TLR4/NF-κB pathway mediated inflammatory gene expression.

Chloral hydrate as a sedating agent for neurodiagnostic procedures in children.

BACKGROUND: This is an updated version of a Cochrane Review published in 2017. Paediatric neurodiagnostic investigations, including brain neuroimaging and electroencephalography (EEG), play an important role in the assessment of neurodevelopmental disorders. The use of an appropriate sedative agent is important to ensure the successful completion of the neurodiagnostic procedures, particularly in children, who are usually unable to remain still throughout the procedure. OBJECTIVES: To assess the effectiveness and adverse effects of chloral hydrate as a sedative agent for non-invasive neurodiagnostic procedures in children. SEARCH METHODS: We searched the following databases on 14 May 2020, with no language restrictions: the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 12 May 2020). CRS Web includes randomised or quasi-randomised controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, the Cochrane Central Register of Controlled Trials (CENTRAL), and the specialised registers of Cochrane Review Groups including Cochrane Epilepsy. SELECTION CRITERIA: Randomised controlled trials that assessed chloral hydrate agent against other sedative agent(s), non-drug agent(s), or placebo. DATA COLLECTION AND ANALYSIS: Two review authors independently evaluated studies identified by the search for their eligibility, extracted data, and assessed risk of bias. Results were expressed in terms of risk ratio (RR) for dichotomous data and mean difference (MD) for continuous data, with 95% confidence intervals (CIs). MAIN RESULTS: We included 16 studies with a total of 2922 children. The methodological quality of the included studies was mixed. Blinding of the participants and personnel was not achieved in most of the included studies, and three of the 16 studies were at high risk of bias for selective reporting. Evaluation of the efficacy of the sedative agents was also underpowered, with all the comparisons performed in small studies. Fewer children who received oral chloral hydrate had sedation failure compared with oral promethazine (RR 0.11, 95% CI 0.01 to 0.82; 1 study; moderate-certainty evidence). More children who received oral chloral hydrate had sedation failure after one dose compared to intravenous pentobarbital (RR 4.33, 95% CI 1.35 to 13.89; 1 study; low-certainty evidence), but there was no clear difference after two doses (RR 3.00, 95% CI 0.33 to 27.46; 1 study; very low-certainty evidence). Children with oral chloral hydrate had more sedation failure compared with rectal sodium thiopental (RR 1.33, 95% CI 0.60 to 2.96; 1 study; moderate-certainty evidence) and music therapy (RR 17.00, 95% CI 2.37 to 122.14; 1 study; very low-certainty evidence). Sedation failure rates were similar between groups for comparisons with oral dexmedetomidine, oral hydroxyzine hydrochloride, oral midazolam and oral clonidine. Children who received oral chloral hydrate had a shorter time to adequate sedation compared with those who received oral dexmedetomidine (MD -3.86, 95% CI -5.12 to -2.6; 1 study), oral hydroxyzine hydrochloride (MD -7.5, 95% CI -7.85 to -7.15; 1 study), oral promethazine (MD -12.11, 95% CI -18.48 to -5.74; 1 study) (moderate-certainty evidence for three aforementioned outcomes), rectal midazolam (MD -95.70, 95% CI -114.51 to -76.89; 1 study), and oral clonidine (MD -37.48, 95% CI -55.97 to -18.99; 1 study) (low-certainty evidence for two aforementioned outcomes). However, children with oral chloral hydrate took longer to achieve adequate sedation when compared with intravenous pentobarbital (MD 19, 95% CI 16.61 to 21.39; 1 study; low-certainty evidence), intranasal midazolam (MD 12.83, 95% CI 7.22 to 18.44; 1 study; moderate-certainty evidence), and intranasal dexmedetomidine (MD 2.80, 95% CI 0.77 to 4.83; 1 study, moderate-certainty evidence). Children who received oral chloral hydrate appeared significantly less likely to complete neurodiagnostic procedure with child awakening when compared with rectal sodium thiopental (RR 0.95, 95% CI 0.83 to 1.09; 1 study; moderate-certainty evidence). Chloral hydrate was associated with a higher risk of the following adverse events: desaturation versus rectal sodium thiopental (RR 5.00, 95% 0.24 to 102.30; 1 study), unsteadiness versus intranasal dexmedetomidine (MD 10.21, 95% CI 0.58 to 178.52; 1 study), vomiting versus intranasal dexmedetomidine (MD 10.59, 95% CI 0.61 to 185.45; 1 study) (low-certainty evidence for aforementioned three outcomes), and crying during administration of sedation versus intranasal dexmedetomidine (MD 1.39, 95% CI 1.08 to 1.80; 1 study, moderate-certainty evidence). Chloral hydrate was associated with a lower risk of the following: diarrhoea compared with rectal sodium thiopental (RR 0.04, 95% CI 0.00 to 0.72; 1 study), lower mean diastolic blood pressure compared with sodium thiopental (MD 7.40, 95% CI 5.11 to 9.69; 1 study), drowsiness compared with oral clonidine (RR 0.44, 95% CI 0.30 to 0.64; 1 study), vertigo compared with oral clonidine (RR 0.15, 95% CI 0.01 to 2.79; 1 study) (moderate-certainty evidence for aforementioned four outcomes), and bradycardia compared with intranasal dexmedetomidine (MD 0.17, 95% CI 0.05 to 0.59; 1 study; high-certainty evidence). No other adverse events were significantly associated with chloral hydrate, although there was an increased risk of combined adverse events overall (RR 7.66, 95% CI 1.78 to 32.91; 1 study; low-certainty evidence). AUTHORS' CONCLUSIONS: The certainty of evidence for the comparisons of oral chloral hydrate against several other methods of sedation was variable. Oral chloral hydrate appears to have a lower sedation failure rate when compared with oral promethazine. Sedation failure was similar between groups for other comparisons such as oral dexmedetomidine, oral hydroxyzine hydrochloride, and oral midazolam. Oral chloral hydrate had a higher sedation failure rate when compared with intravenous pentobarbital, rectal sodium thiopental, and music therapy. Chloral hydrate appeared to be associated with higher rates of adverse events than intranasal dexmedetomidine. However, the evidence for the outcomes for oral chloral hydrate versus intravenous pentobarbital, rectal sodium thiopental, intranasal dexmedetomidine, and music therapy was mostly of low certainty, therefore the findings should be interpreted with caution. Further research should determine the effects of oral chloral hydrate on major clinical outcomes such as successful completion of procedures, requirements for an additional sedative agent, and degree of sedation measured using validated scales, which were rarely assessed in the studies included in this review. The safety profile of chloral hydrate should be studied further, especially for major adverse effects such as oxygen desaturation.

Kamishoyosan potentiates pentobarbital-induced sleep in socially isolated, ovariectomized mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Sleep disorders are among the most common symptoms in both peri- and post-menopausal women. Kamishoyosan (KSS) is a Kampo medicine prescribed for the treatment of sleep disorders in menopausal women in Japan. However, its precise mechanism of action remains unclear. AIM OF THE STUDY: In the present study, we developed a new animal model of menopausal sleep disorders by inducing social isolation stress in ovariectomized mice. Using pentobarbital-induced sleeping time as an index, we aimed to investigate the effects of KSS and involvement of the benzodiazepine receptors. MATERIALS AND METHODS: Eight-week-old, female ddY mice were ovariectomized or subjected to a sham operation (control) and housed in social isolation or groups for 9 weeks. The animals were divided into four groups, group-housed sham-operated, isolated sham-operated, group-housed ovariectomized, and socially isolated ovariectomized. Pentobarbital (50 mg/kg) was administered intraperitoneally (i.p.). Sleeping time was considered the period between the loss of righting reflex and its return (up to 180 min). KSS was administered orally (p.o.) 60 min before the test. Diazepam and flumazenil were administered i.p. 30 and 45 min before the test, respectively. On the day after administration, the mice were euthanized, and their uteri were weighed. RESULTS: Socially isolated, ovariectomized mice had shorter sleeping times than mice in all other groups. In mice with intact ovaries, diazepam (1 mg/kg, i.p.) considerably prolonged the pentobarbital-induced sleeping time, but KSS (30-1000 mg/kg, p.o.) did not. However, KSS (100 mg/kg, p.o.) significantly prolonged the pentobarbital-induced sleeping time in socially isolated ovariectomized mice. The prolongation of sleeping time mediated by KSS was reversed by flumazenil (3 mg/kg, i.p.). CONCLUSIONS: KSS potentiated pentobarbital-induced sleep in socially isolated, ovariectomized mice, and the benzodiazepine receptors are possibly involved in its pharmacological mechanism. These findings suggest that KSS is beneficial for the treatment of menopausal sleep disorders.

Acute toxicity and micronucleus test of conotoxin lt14a in mice.

Conotoxins, which target ion channels or neurotransmitter receptors with high specificity, are valuable in drug development for pain, epilepsy and other neurological diseases. However, the toxicology of conotoxins is rarely reported. In this study, we primarily researched parts of the pharmacological and toxicological properties of an analgesic conotoxin lt14a. Three doses of lt14a (1, 5 and 10 mg/kg) could prolong the pentobarbital-induced sleep time of mice and showed no significant effect on the spontaneous locomotor activity of mice. Three doses of lt14a (50, 100 and 200 mg/kg) did not increase micronucleus rate in the micronucleus test. In addition, three doses of lt14a (200, 500 and 1000 mg/kg) showed no pathological change on the heart or brain of mice in the acute toxicity test. The high dose of lt14a (1000 times the effective analgesic dose) had a certain damaging effect on the liver and lung according to serological detection and histopathology. As part of the preclinical studies, our results provide acute toxicity and mutagenicity evaluation of the promising analgesic conotoxin lt14a.

Intraperitoneal injection of sodium pentobarbital has the potential to elicit pain in adult rats (Rattus norvegicus).

An effective and pain-free killing method is required to achieve the goal of euthanasia, a "good death". Overdose of sodium pentobarbital (PB) by intraperitoneal (IP) injection is a widely accepted technique in laboratory rats, but questions remain regarding pain associated with administration. As PB rapidly causes sedation and loss of consciousness, most studies have relied on indirect evidence of pain. The objective of this study was to assess pain associated with IP PB using an appropriate vehicle control. Adult male and female Sprague Dawley (SD) and female Wistar rats (N = 84) were block randomised by sex and strain to receive one of three treatments: 1) 800 mg/kg PB (pH 11), 2) saline or 3) vehicle controls (pH 11 or 12.5). Behavior (Rat Grimace Scale (RGS), writhing, back arching) was evaluated at baseline, before loss of righting reflex (LORR, PB group), and at 80s, 151s and 10 min post-injection (PI; saline and vehicle control groups). In the PB group, mean time to LORR was 78 ± 7.9 seconds. In the vehicle control groups, RGS scores were increased at 151s PI (SD: p = 0.0002, 95%CI 0.73 to 0.20) from baseline, as was relative frequency of writhing (SD: p < 0.0001; Wistar; p = 0.0004). RGS scores remained elevated 10 mins PI (SD: p = 0.0005, 95%CI 0.71 to 0.18; Wistar: p = 0.0234, 95%CI 0.91 to 0.07) but the relative frequency of writhing did not (p > 0.999). The RGS scores and the relative frequency of writhing remained low in the PB and saline groups (p > 0.05). These results show that, vehicle controls for IP PB result in signs associated with pain, pain may not be experienced following IP PB when LORR occurs quickly, and that the effects of PB limit behavioral pain assessments.

Verification and Defined Dosage of Sodium Pentobarbital for a Urodynamic Study in the Possibility of Survival Experiments in Female Rat.

OBJECTIVES: To evaluate the effects of pentobarbital dosages on lower urinary tract function and to define an appropriate dosage of sodium pentobarbital that would be suitable for urodynamic studies in which recovery from anesthesia and long term survive were needed for subsequent experiment. METHODS: Twenty-four 8-week-old, female, virgin, Sprague-Dawley rats (200-250 g) were used in this study. Rats in study groups received gradient doses of pentobarbital intraperitoneally, and those in the control group received urethane intraperitoneally. External urethral sphincter electromyography (EUS-EMG) was recorded simultaneously during cystometry and leak point pressure tests. The toe-pinch reflex was used to determine the level of anesthesia. RESULTS: Micturition was normally induced in both the urethane group and 32 mg/kg pentobarbital group. However, in groups of 40 mg/kg or 36 mg/kg pentobarbital, micturition failed to be induced; instead, nonvoiding contractions accompanied by EUS-EMG tonic activity were observed. There were no significant differences in leak point pressure or EUS-EMG amplitude or frequency between the urethane and 32 mg/kg pentobarbital groups. CONCLUSIONS: This study confirmed significant dose-dependent effects of pentobarbital on lower urinary tract function and 32 mg/kg pentobarbital as an appropriate dosage for recovery urodynamic testing, which enable the achievement of expected essential micturition under satisfactory anesthesia in female rats.

Patterns of neural activity in the mouse brain: Wakefulness vs. General anesthesia.

In light of the general shift from rats to mice as the leading rodent model in neuroscience research we used c-Fos expression as a tool to survey brain regions in the mouse in which neural activity differs between the states of wakefulness and pentobarbital-induced general anesthesia. The aim was to complement prior surveys carried out in rats. In addition to a broad qualitative review, 28 specific regions of interest (ROIs) were evaluated quantitatively. Nearly all ROIs in the cerebral cortex showed suppressed activity during anesthesia. Subcortically, however, some ROIs showed suppression, some showed little change, and some showed increased activity. The overall picture was similar to the rat. Special attention was devoted to ROIs significantly activated during anesthesia, as such loci might actively drive the transition to anesthetic unconsciousness rather than responding passively to inhbitory agents distributed globally (the "wet blanket" hypothesis). Twelve such "anesthesia-on" ROIs were identified: the paraventricular hypothalamic nucleus, supraoptic nucleus, tuberomamillary nucleus, lateral habenular nucleus, dentate gyrus, nucleus raphe pallidus, central amygdaloid nucleus, perifornical lateral hypothalamus, ventro-lateral preoptic area, lateral septum, paraventricular thalamic nucleus and zona incerta. The same primary anti-FOS antibody was used in all mice, but two alternative reporter systems were employed: ABC-diaminobenzidine and the currently more popular AlexaFluor488. Fluorescence tagging revealed far fewer FOS-immunoreactive neurons, sounding an alert that the reporter system chosen can have major effects on results obtained.

Nrf2 Antioxidative System is Involved in Cytochrome P450 Gene Expression and Activity: A Delay in Pentobarbital Metabolism in Nrf2-Deficient Mice.

NF-E2-related factor 2 (Nrf2) is a transcriptional regulator of biologic defense proteins, such as antioxidant proteins and phase II detoxification enzymes. Cytochrome P450 (P450) enzymes have been shown to regulate phase I metabolism of various drugs and are partially regulated by Nrf2; however, the influence of Nrf2 on drug pharmacokinetics is not known. Here, we showed that Nrf2 depletion prolonged the effect of pentobarbital, a sleep-promoting drug. Pretreatment with phenobarbital, a P450 inducer, shortens the sleeping time associated with pentobarbital-induced sedation in wild-type (WT) mice; however, this effect was not observed in Nrf2-/- mice. Furthermore, the blood pentobarbital concentration was higher in Nrf2-/- mice than in WT mice at 30-60 minutes, and the phenobarbital-induced enhancement of its clearance was attenuated in Nrf2-/- mice compared with WT mice. Total P450 content was decreased in Nrf2-/- mouse livers, and the phenobarbital-induced increase in P450 content was lower in Nrf2-/- mice than WT mice. Cyp1a2, Cyp2a5, Cyp2c29, and Cyp2e1 gene expression levels under physiologic conditions and Cyp1a2, Cyp2a5, and Cyp2b10 gene expression levels under phenobarbital-treated conditions were lower in Nrf2-/- mice compared with WT mice. Additionally, pentobarbital metabolism in liver microsomes was attenuated by Nrf2 depletion. Taken together, these findings suggested that Nrf2 influenced pentobarbital pharmacokinetics through the regulation of drug metabolism and P450 gene expression. Thus, Nrf2-mediated regulation of P450 may contribute to the biologic defense against increased reactive oxygen species production. SIGNIFICANCE STATEMENT: NF-E2-related factor 2 (Nrf2) plays a critical role in the cellular defense against oxidative stress. Nrf2-/- mice with reduced ability to eliminate reactive oxygen species (ROS) showed a significant delay in emergence from pentobarbital-induced sleep, which was associated with decreased P450 activities and gene expression. Our findings provide that Nrf2 dysfunction or ROS that exceed a threshold level of the eliminating ability of the Nrf2 system may reduce P450 activity.

Localized anesthesia of a specific brain region using ultrasound-responsive barbiturate nanodroplets.

Background: Targeted neuromodulation is a valuable technique for the study and treatment of the brain. Using focused ultrasound to target the local delivery of anesthetics in the brain offers a safe and reproducible option for suppressing neuronal activity. Objective: To develop a potential new tool for localized neuromodulation through the triggered release of pentobarbital from ultrasound-responsive nanodroplets. Method: The commercial microbubble contrast agent, Definity, was filled with decafluorobutane gas and loaded with a lipophilic anesthetic drug, before being condensed into liquid-filled nanodroplets of 210 ± 80 nm. Focused ultrasound at 0.58 MHz was found to convert nanodroplets into microbubbles, simultaneously releasing the drug and inducing local anesthesia in the motor cortex of rats (n=8). Results: Behavioral analysis indicated a 19.1 ± 13% motor deficit on the contralateral side of treated animals, assessed through the cylinder test and gait analysis, illustrating successful local anesthesia, without compromising the blood-brain barrier. Conclusion: Pentobarbital-loaded decafluorobutane-core Definity-based nanodroplets are a potential agent for ultrasound-triggered and targeted neuromodulation.

Evaluating Intrahepatic and Intraperitoneal Sodium Pentobarbital or Ethanol for Mouse Euthanasia.

Intraperitoneal (IP) injection of sodium pentobarbital (PB) is an accepted method of euthanasia for mice. However, this method has important drawbacks, including the potential for pain or misinjection. The objective of this prospective, randomized, blinded study was to determine whether intrahepatic (IH) injection of PB is more effective than IP delivery for mouse euthanasia. Secondary objectives were to: 1) determine whether IP ethanol (ET) is a suitable alternative to PB and 2) study the effect of isoflurane anesthesia on euthanasia with either PB or ET. Eighty adult CD1 mice were randomly assigned to 6 different treatment groups, were euthanized by using IP or IH injections of either PB or ET, and were either anesthetized or conscious before injection. Variables of interest were: 1) misinjection rates (based on necropsy evaluation), 2) time from injection to apnea and 3) time to cessation of heartbeat (CHB). The misinjection rate for IH injections was 93% (28/30). Two successful IH injections resulted in death within 4 s, but this method cannot be recommended due to the possibility for intrathoracic injection ( n = 4). In nonanesthetized mice, time to apnea and CHB was significantly shorter with IP ET (apnea: 72.5 s [median], CHB: 115 s) than with IP PB (apnea: 136 s, CHB: 176 s). Anesthesia at time of injection was associated with a shorter CHB time for IP PB. These data show the difficulty in achieving successful IH injections in mice, but confirm that IP ET is a viable and potentially superior alternative to IP PB. Lastly, anesthesia can shorten time to death after IP injection of PB.

Brain interstitial fluid drainage and extracellular space affected by inhalational isoflurane: in comparison with intravenous sedative dexmedetomidine and pentobarbital sodium.

Brain interstitial fluid drainage and extracellular space are closely related to waste clearance from the brain. Different anesthetics may cause different changes of brain interstitial fluid drainage and extracellular space but these still remain unknown. Herein, effects of the inhalational isoflurane, intravenous sedative dexmedetomidine and pentobarbital sodium on deep brain matters' interstitial fluid drainage and extracellular space and underlying mechanisms were investigated. When compared to intravenous anesthetic dexmedetomidine or pentobarbital sodium, inhalational isoflurane induced a restricted diffusion of extracellular space, a decreased extracellular space volume fraction, and an increased norepinephrine level in the caudate nucleus or thalamus with the slowdown of brain interstitial fluid drainage. A local administration of norepinephrine receptor antagonists, propranolol, atipamezole and prazosin into extracellular space increased diffusion of extracellular space and interstitial fluid drainage whilst norepinephrine decreased diffusion of extracellular space and interstitial fluid drainage. These findings suggested that restricted diffusion in brain extracellular space can cause slowdown of interstitial fluid drainage, which may contribute to the neurotoxicity following the waste accumulation in extracellular space under inhaled anesthesia per se.

Review of Intraperitoneal Injection of Sodium Pentobarbital as a Method of Euthanasia in Laboratory Rodents.

Euthanasia is one of the most commonly performed procedures in biomedical research, involving tens of millions of animals in North America and Europe every year. The use of sodium pentobarbital, injected intraperitoneally, for killing rodents is described as an acceptable technique by the AVMA and CCAC euthanasia guidelines. This drug and route are recommended over inhalant anesthetics, carbon dioxide, and physical methods for ethical and aesthetic reasons as well as efficiency. However, a growing body of evidence challenges the efficacy and utility of intraperitoneal pentobarbital. This methodology has been described as inconsistent and may induce pain and stress. With these considerations in mind, a review of the literature is needed to assess the evidence surrounding this killing method, the associated welfare implications, and potential for refinement.

Moringa oleifera Lam Seed Oil Augments Pentobarbital-Induced Sleeping Behaviors in Mice via GABAergic Systems.

Moringa oleifera Lam. (MO), which is widely consumed as both food and herbal medicine in tropical and subtropical regions, has a wide spectrum of health benefits. Yet, whether the oil obtained from MO seeds could affect (improve) the sleep activity remains unclear. Herein, we used the locomotor activity, pentobarbital-induced sleeping, and pentetrazol-induced convulsions test to examine sedative-hypnotic effects (SHE) of MO oil (MOO) and explored the underlying mechanisms. Besides, the main components of MOO like oleic acid, ß-Sitosterol, and Stigmasterol were also evaluated. The results showed that they possessed good SHE. Except for oleic acid and Stigmasterol, they could significantly elevate γ-amino butyric acid (GABA) and reduce glutamic acid (Glu) levels in the hypothalamus of mice. Moreover, SHE was blocked by picrotoxin, flumazenil, and bicuculline, except for oleic acid, which could not be antagonized by picrotoxin. Molecular mechanisms showed that MOO and ß-Sitosterol significantly upregulated the amount of protein-level expression of Glu decarboxylase-65 (GAD65) and α1-subunit of GABAA receptors in the hypothalamus of mice, not affecting GAD67, γ2 subunits. These data indicated that MOO modulates sleep architectures via activation of the GABAA-ergic systems.

Encapsulation of Escherichia coli strain Nissle 1917 in a chitosan-alginate matrix by combining layer-by-layer assembly with CaCl2 cross-linking for an effective treatment of inflammatory bowel diseases.

Escherichia coli strain Nissle 1917 (EcN) has been widely shown to effectively treat inflammatory bowel diseases (IBDs). Unfortunately, after oral administration, EcN viability dramatically decreases due to severe environmental factors, including low gastric pH, temperature and osmotic pressure. To address these challenges and improve oral bio-availability, this study utilized layer-by-layer assembly (LbL) and ionic cross-linking with CaCl2 as a method of EcN encapsulation (GEcN). Upon examination, GEcN cells were shown to maintain their ability to grow and proliferate, but had a slightly longer stationary phase (10 h) relative to free EcN (4 h). When exposed to simulated gastric fluid (SGF), a higher number of GEcN cells survived up to 12 h when compared to the other groups. To assess the therapeutic effect of EcN encapsulation in vivo, a TNBS-induced colitis rat model was established. When compared with the oral administration of free EcN, GEcN exhibited a significantly enhanced anti-inflammatory effect. Furthermore, GEcN treatment showed a lower disease activity index (DAI), decreased pro-inflammatory cytokine expression (MPO, TNF-α, IL-6) and increased anti-inflammatory cytokine expression (IL-10). Additionally, rats that received GEcN had much higher ZO-1 expression levels. These results suggest that EcN encapsulation in a chitosan-alginate matrix when utilizing the LbL assembly with CaCl2 cross-linking can improve probiotic viability in a gastric environmental and thereby offer a more effective treatment for IBDs.

Pathological consequences of low atmospheric pressure stunning in broiler chickens.

Low atmospheric pressure stunning (LAPS) is a novel approach to pre-slaughter stunning of chickens using progressive hypobaric hypoxia by the application of gradual decompression (280s cycle) according to a set of prescribed pressure curves. Low atmospheric pressure stunning produces a non-recovery state. Concerns have been raised relating to the possible pathological and welfare consequences of expansion of air in the body during LAPS. In a randomised trial, we compared the gross pathology of broilers exposed to LAPS with a control group euthanised by intravenous injection of pentobarbital sodium (60 mixed sex broilers per treatment). The birds were exposed to each treatment in triplets and all birds were subject to necropsy examination to detect and score (1 to 5, minimal to severe) haemorrhagic lesions or congestion for all major organs and cavities (e.g. air sacs, joints, ears and heart) as well as external assessment for product quality (e.g. wing tips). Behavioural data (latency to loss of posture and motionless) and chamber cycle data (temperature, humidity, pressure and oxygen availability) confirmed that LAPS had been applied in a manner representative of the commercial process. All of the organs observed were structurally intact for both treatment groups. No lesions were observed in the external ears, oral cavity, tracheal lumen, crop and air sacs of birds from either treatment group. There was no difference between treatments in the wingtips, nasal turbinates, thymus, biceps femoralis and colon. Haemorrhagic lesions were observed in the calvaria, brains, hearts and lungs of both treatment groups, but lesions in these areas were more severe in the LAPS treatment group. It was not possible to distinguish between pathological changes induced by decompression or recompression. In the barbiturate group, more severe haemorrhagic lesions were observed in the superficial pectoral muscles as well as greater congestion of the infraorbital sinuses, liver, spleens, duodenum, kidneys and gonads. These findings provide evidence that LAPS did not result in distension of the intestines and air sacs sufficient to cause changes, which were grossly visible on postmortem examination. There was also no evidence of barotrauma in the ears and sinuses. The pathological changes observed in the barbiturate treatment were as expected based on barbiturate toxicity. Low atmospheric pressure stunning appears to produce pathological changes by a variety of well-established mechanisms, and while these pathological data have limited value as welfare indicators, the results confirm that organ integrity was not compromised by the process.

Perfused murine heart optical transmission spectroscopy using optical catheter and integrating sphere: Effects of ischemia/reperfusion.

Tissue transmission optical absorption spectroscopy provides dynamic information on metabolism and function. Murine genetic malleability makes it a major model for heart research. The diminutive size of the mouse heart makes optical transmission studies challenging. Using a perfused murine heart center mounted in an integrating sphere for light collection with a ventricular cavity optical catheter as an internal light source provided an effective method of optical data collection in this model. This approach provided high signal to noise optical spectra which when fit with model spectra provided information on tissue oxygenation and redox state. This technique was applied to the study of cardiac ischemia and ischemia reperfusion which generates extreme heart motion, especially during the ischemic contracture. The integrating sphere reduced motion artifacts associated with a fixed optical pickup and methods were developed to compensate for changes in tissue thickness. During ischemia, rapid decreases in myoglobin oxygenation occurred along with increases in cytochrome reduction levels. Surprisingly, when ischemic contracture occurred, myoglobin remained fully deoxygenated, while the cytochromes became more reduced consistent with a further, and critical, reduction of mitochondrial oxygen tension during ischemic contraction. This optical arrangement is an effective method of monitoring murine heart metabolism.