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Neuroscience Letters Apr 2023Pentobarbital-induced anesthesia is believed to be mediated by enhancement of the inhibitory action of γ-aminobutyric acid (GABA)ergic neurons in the central nervous...
Pentobarbital-induced anesthesia is believed to be mediated by enhancement of the inhibitory action of γ-aminobutyric acid (GABA)ergic neurons in the central nervous system. However, it is unclear whether all components of anesthesia induced by pentobarbital, such as muscle relaxation, unconsciousness, and immobility in response to noxious stimuli, are mediated only through GABAergic neurons. Thus, we examined whether the indirect GABA and glycine receptor agonists gabaculine and sarcosine, respectively, the neuronal nicotinic acetylcholine receptor antagonist mecamylamine, or the N-methyl-d-aspartate receptor channel blocker MK-801 could enhance pentobarbital-induced components of anesthesia. Muscle relaxation, unconsciousness, and immobility were evaluated by grip strength, the righting reflex, and loss of movement in response to nociceptive tail clamping, respectively, in mice. Pentobarbital reduced grip strength, impaired the righting reflex, and induced immobility in a dose-dependent manner. The change in each behavior induced by pentobarbital was roughly consistent with that in electroencephalographic power. A low dose of gabaculine, which significantly increased endogenous GABA levels in the central nervous system but had no effect on behaviors alone, potentiated muscle relaxation, unconsciousness, and immobility induced by low pentobarbital doses. A low dose of MK-801 augmented only the masked muscle-relaxing effects of pentobarbital among these components. Sarcosine enhanced only pentobarbital-induced immobility. Conversely, mecamylamine had no effect on any behavior. These findings suggest that each component of anesthesia induced by pentobarbital is mediated through GABAergic neurons and that pentobarbital-induced muscle relaxation and immobility may partially be associated with N-methyl-d-aspartate receptor antagonism and glycinergic neuron activation, respectively.
Topics: Mice; Animals; Receptors, N-Methyl-D-Aspartate; Pentobarbital; Dizocilpine Maleate; Sarcosine; Mecamylamine; gamma-Aminobutyric Acid; Unconsciousness
PubMed: 36907265
DOI: 10.1016/j.neulet.2023.137175 -
Journal of Ocular Pharmacology and... Mar 2022Anesthesia is necessary to conduct rodent electroretinograms (ERGs). We evaluated utility of the α2-agonist medetomidine versus xylazine for ERG studies in nondiabetic...
Anesthesia is necessary to conduct rodent electroretinograms (ERGs). We evaluated utility of the α2-agonist medetomidine versus xylazine for ERG studies in nondiabetic and diabetic rats. Pentobarbital was included as a comparator. Male Sprague-Dawley rats, with and without streptozotocin (STZ)-induced diabetes, were anesthetized with medetomidine (1 mg/kg), xylazine (10 mg/kg) (both with ketamine 75 mg/kg), or pentobarbital (70 mg/kg). The depth of anesthesia was assessed, and if adequate, scotopic ERGs were recorded. Blood glucose was monitored. In nondiabetic rats, all three agents induced satisfactory anesthesia, but with differing durations: medetomidine > pentobarbital > xylazine. ERG responses were similar under medetomidine and xylazine, but relatively reduced under pentobarbital. Both α2-agonists (but not pentobarbital) elicited marked hyperglycemia (peak values 316.1 ± 42.6 and 300.3 ± 29.5 mg/dL, respectively), persisting for 12 h. In diabetic rats, elevated blood glucose concentrations were not affected by any of the agents, but the depth of anesthesia under medetomidine and xylazine was inadequate for ERG recording. In nondiabetic rats, medetomidine and xylazine elicited comparable effects on ERGs that differ from pentobarbital, but both perturbed glucose metabolism, potentially confounding experimental outcomes. In STZ-diabetic rats, neither α2-agent provided adequate anesthesia, while pentobarbital did so. Problems with α2-anesthetic agents, including medetomidine, must be recognized to ensure meaningful interpretation of experimental results.
Topics: Adrenergic Agents; Anesthesia; Animals; Diabetes Mellitus, Experimental; Male; Medetomidine; Pentobarbital; Rats; Rats, Sprague-Dawley; Xylazine
PubMed: 34964655
DOI: 10.1089/jop.2021.0084 -
Journal of Controlled Release :... Apr 2021Focused ultrasound (FUS) offers an attractive tool for non-invasive neuromodulation, addressing a clinical need to develop more minimally invasive approaches that are...
Focused ultrasound (FUS) offers an attractive tool for non-invasive neuromodulation, addressing a clinical need to develop more minimally invasive approaches that are safer, more tolerable and versatile. In combination with a cavitation agent, the effects of ultrasound can be amplified and localized for therapy. Using c-Fos expression mapping, we show how ultrasound-sensitive nanodroplets can be used to induce either neurosuppression or neurostimulation, without disrupting the blood-brain barrier in rats. By repurposing a commercial ultrasound contrast agent, Definity, lipid-shell decafluorobutane-core nanodroplets of 212.5 ± 2.0 nm were fabricated and loaded with or without pentobarbital. FUS was delivered with an atlas-based targeting system at 1.66 MHz to the motor cortex of rats, using a feedback-controller to detect successful nanodroplet vaporization and drug release. Neuromodulation was quantified through changes in sensorimotor function and c-Fos expression. Following FUS-triggered delivery, sham nanodroplets induced a 22.6 ± 21% increase in local c-Fos expression, whereas pentobarbital-loaded nanodroplets induced a 21.7 ± 13% decrease (n = 6). Nanodroplets, combined with FUS, offer an adaptable tool for neuromodulation, through local delivery of small molecule anesthetics or targeted mechanical effects.
Topics: Animals; Blood-Brain Barrier; Contrast Media; Drug Delivery Systems; Drug Liberation; Pentobarbital; Rats; Ultrasonography
PubMed: 33600879
DOI: 10.1016/j.jconrel.2021.02.010 -
Journal of Food and Drug Analysis Jun 2023Ashwagandha (Withania somnifera L. Dunal), an Indian medicinal plant that has been used for centuries to treat insomnia, exhibits a variety of biological activities,...
Ashwagandha (Withania somnifera L. Dunal), an Indian medicinal plant that has been used for centuries to treat insomnia, exhibits a variety of biological activities, such as improving cognitive function, immunity and anxiety. In this study, the effect of enzyme-treated Ashwagandha root extract (EA) and on sleep was evaluated using rodent models. Starch contained in the Ashwagandha root extract was removed by amylase treatment to prepare EA. To evaluate the sleep-promoting activity of EA, a pentobarbital-induced sleep test and electroencephalogram analysis were performed. In addition, the sleep-promoting mechanism of EA was elucidated by analyzing the expression of sleep-related receptors. In the pentobarbital-induced sleep test, EA dose-dependently increased sleep duration. Additionally, electroencephalogram analysis revealed that EA significantly increased δ-wave and non-rapid eye movement sleep times, which are involved in deep sleep, thereby improving sleep quality and quantity. EA also effectively relieved caffeine-induced insomnia symptoms. Furthermore, the γ-aminobutyric acid (GABA) content in the brain and mRNA and protein expression of GABA, GABA, and serotonin receptors were significantly increased by EA compared to the normal group. In particular, EA showed sleep-promoting activity by binding to various GABAA receptor sites. Collectively, EA exhibited sleep-promoting activity through the GABAergic system and may be used as a functional material to improve sleep deprivation.
Topics: Receptors, GABA; Withania; Sleep Initiation and Maintenance Disorders; Pentobarbital; Amylases; Plant Extracts; Sleep; gamma-Aminobutyric Acid
PubMed: 37335157
DOI: 10.38212/2224-6614.3456 -
Analytical Chemistry Oct 2022Barbiturates are highly susceptible to dissociation in mass spectrometry (MS) because of their long side chains combined with a nonaromatic ring consisting of several...
Barbiturates are highly susceptible to dissociation in mass spectrometry (MS) because of their long side chains combined with a nonaromatic ring consisting of several carbonyl and amine groups. As a result, they exhibit extensive α-cleavage and subsequent rearrangement, making the identification of these compounds difficult. Although a library of electron ionization MS (EIMS) is available, most barbiturates have very similar fragment patterns. Accordingly, it would be desirable to develop a technique for soft ionization, providing a molecular ion and large fragment ions as well. In this study, a molecular ion was clearly observed, in addition to large fragment ions, for a variety of barbiturates based on multiphoton ionization MS (MPIMS) using a tunable ultraviolet femtosecond laser as the ionization source (fs-LIMS). This favorable result was achieved when the optimal laser wavelength for minimizing the excess energy remaining in the ionic state was used. An examination of the photofragmentation pathways suggested that an H atom in the side chain was abstracted by an oxygen atom in the carbonyl group in the ring structure thus initiating fragmentation and subsequent rearrangement. Barbiturates that are substituted with alkyl groups (amobarbital and pentobarbital) had narrower spectral regions for optimal ionization than the other barbiturates with alkyl and alkenyl groups (butalbital and secobarbital) and more with alkyl and phenyl groups (phenobarbital). All of the barbiturates studied provided unique mass spectral patterns in fs-LIMS, which was useful for the reliable identification of these compounds in practical trace analysis.
Topics: Secobarbital; Amobarbital; Pentobarbital; Barbiturates; Phenobarbital; Mass Spectrometry; Ions; Oxygen; Amines
PubMed: 36229898
DOI: 10.1021/acs.analchem.2c03077 -
Journal of the American Association For... May 2020Euthanasia 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... (Review)
Review
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.
Topics: Anesthetics, Inhalation; Animal Welfare; Animals; Animals, Laboratory; Biomedical Research; Euthanasia, Animal; Guidelines as Topic; Injections, Intraperitoneal; Pain; Pentobarbital; Rodentia
PubMed: 32156325
DOI: 10.30802/AALAS-JAALAS-19-000081 -
BioMed Research International 2020To 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...
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.
Topics: Anesthetics, Intravenous; Animals; Electromyography; Female; Pentobarbital; Rats; Rats, Sprague-Dawley; Urethane; Urethra; Urinary Bladder; Urination; Urodynamics
PubMed: 32626750
DOI: 10.1155/2020/6109497 -
Anesthesiology Mar 1989The effects of 3.0 mg.kg-1 fentanyl on cerebral and peripheral hemodynamics alone and when combined with subanesthetic doses of pentobarbital (4.0 mg.kg-1), were studied... (Comparative Study)
Comparative Study
The effects of 3.0 mg.kg-1 fentanyl on cerebral and peripheral hemodynamics alone and when combined with subanesthetic doses of pentobarbital (4.0 mg.kg-1), were studied in 11 unanesthetized, newborn lambs, in whom catheters had been previously inserted. After a control period, drugs were administered at 20-min intervals by intravenous bolus injection. Group 1 animals (n = 5) received fentanyl, pentobarbital, and naloxone (0.01 mg.kg-1), whereas Group 2 animals (n = 6) had the order of fentanyl and pentobarbital reversed. All animals responded to pain (withdrawal to tail clamping) and appeared conscious (eyes open, alert to sound) when either fentanyl or barbiturate was given alone. The combination of drugs, however, produced complete unresponsiveness. All of these effects were reversed by naloxone. Cardiac output did not change after either fentanyl or pentobarbital was administered individually but decreased significantly (29% in Group 1, 21% in Group 2) after administration of the combination of both. Mean arterial pressure and heart rate were unchanged. Cerebral blood flow, oxygen (O2) transport, and O2 consumption did not change after either administration of fentanyl or pentobarbital alone but decreased significantly after both (22%, 30%, 19%, respectively, in Group 1 and 35%, 40%, 38%, respectively, in Group 2). The decrease in cerebral O2 transport nearly paralleled the decrease in cerebral O2 consumption such that the ratio, the fractional O2 extraction, increased slightly. Fentanyl decreased kidney blood flow alone (24%) and in combination with pentobarbital (25%), although pentobarbital did so only when combined with fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Animals; Animals, Newborn; Brain; Cardiac Output; Cerebrovascular Circulation; Drug Interactions; Fentanyl; Hemodynamics; Naloxone; Oxygen Consumption; Pentobarbital; Sheep
PubMed: 2923293
DOI: 10.1097/00000542-198903000-00016 -
International Journal of Experimental... Feb 2021This study aims to compare the influence of different anaesthesia methods on the mechanisms involved in the development of hepatoblastoma (HB). HB rabbit models were...
This study aims to compare the influence of different anaesthesia methods on the mechanisms involved in the development of hepatoblastoma (HB). HB rabbit models were constructed and divided into three groups: disoprofol, pentobarbital sodium and HB groups. After anaesthesia, rabbit blood was collected from the tail vein. Haematological analysis (platelets) and an ELISA was used to measure the thrombopoietin (TPO) and 5-hydroxytryptamine (5-HT). Flow cytometry was used to determine expression of P-selectin and PAF. The expression of 5-HTR2B, PCNA, vWF, P70s6k, 4E-BP1, mTOR and FRAP was determined in the tumour itself or in vascular tissues obtained from the rabbits. The platelet content in the disoprofol group. The content or expression of TPO, 5-HT, P-selectin, PAF, 5-HTR2B, PCNA, vWF, P70s6k, 4E-BP1, mTOR and FRAP was significantly higher in the disoprofol group compared to pentobarbital sodium and HB groups. Expression of these molecules was much higher in the pentobarbital sodium group compared with the HB group. These findings suggest that disoprofol anaesthesia can promote HB development via the mTOR/p70S6K1 and FRAP signalling pathway.
Topics: Animals; Hepatoblastoma; Hypnotics and Sedatives; Liver Neoplasms; Pentobarbital; Platelet Activation; Propofol; Rabbits; Signal Transduction
PubMed: 33410572
DOI: 10.1111/iep.12378 -
Neuropsychopharmacology : Official... Jan 2023Neurosteroids that positively modulate GABA receptors are among a growing list of rapidly acting antidepressants, including ketamine and psychedelics. To develop...
Neurosteroids that positively modulate GABA receptors are among a growing list of rapidly acting antidepressants, including ketamine and psychedelics. To develop increasingly specific treatments with fewer side effects, we explored the possibility of EEG signatures in mice, which could serve as a cross-species screening tool. There are few studies of the impact of non-sedative doses of rapid antidepressants on EEG in either rodents or humans. Here we hypothesize that EEG features may separate a rapid antidepressant neurosteroid, allopregnanolone, from other GABA positive modulators, pentobarbital and diazepam. Further, we compared the actions GABA modulators with those of ketamine, an NMDA antagonist and prototype rapid antidepressant. We examined EEG spectra during active exploration at two cortical locations and examined cross-regional and cross-frequency interactions. We found that at comparable doses, the effects of allopregnanolone, despite purported selectivity for certain GABAR subtypes, was indistinguishable from pentobarbital during active waking exploration. The actions of diazepam had recognizable common features with allopregnanolone and pentobarbital but was also distinct, consistent with subunit selectivity of benzodiazepines. Finally, ketamine exhibited no distinguishing overlap with allopregnanolone in the parameters examined. Our results suggest that rapid antidepressants with different molecular substrates may remain separated at the level of large-scale ensemble activity, but the studies leave open the possibility of commonalities in more discrete circuits and/or in the context of a dysfunctional brain.
Topics: Humans; Mice; Animals; Pregnanolone; Ketamine; Pentobarbital; Receptors, GABA-A; Diazepam; Neurosteroids; Antidepressive Agents; gamma-Aminobutyric Acid; Electroencephalography
PubMed: 36168047
DOI: 10.1038/s41386-022-01450-x