Comparison of Two Experimental Mouse Dry Eye Models through Inflammatory Gene Set Enrichment Analysis Based on a Multiplexed Transcriptomic Approach.

The goal of this study was to explore the specific signaling pathways related to inflammation in two experimental mouse dry eye (EDE) models. Female C57BL/6 mice housed for 10 days in a controlled desiccative environment were either treated with scopolamine (EDE-1; n = 18) or subjected to extraorbital lacrimal gland excision bilaterally (EDE-2; n = 10). Non-induced mice (n = 20) served as healthy controls. A corneal fluorescein staining (CFS) scoring was used at baseline through to day (D) 10 to evaluate epitheliopathy. At D10, corneas and conjunctivas were collected for multiplexed transcriptomic analysis with the NanoString® mouse inflammatory CodeSet. Both EDE-1 and EDE-2 mice presented a change in corneal integrity, with a significant increase in CFS scores at D10. More gene transcripts were identified in EDE-2 compared with EDE-1 (116 vs. 96, respectively), and only a few were common to both models, 13 for the cornea and 6 for the conjunctiva. The gene functional annotation analysis revealed that the same inflammatory pathways were involved in both models. Comparative profiling of gene expression in the two EDE models leads to the identification of various targets and signaling pathways, which can be extrapolated to and confirmed in human disease.

Discovery of 4-arylquinoline-2-carboxamides, highly potent and selective class of mGluR2 negative allosteric modulators: From HTS to activity in animal models.

Antagonism of the mGluR2 receptor has the potential to provide therapeutic benefit to cognitive disorders by elevating synaptic glutamate, the primary excitatory neurotransmitter in the brain. Selective antagonism of the mGluR2 receptor, however, has so far been elusive, given the very high homology of this receptor with mGluR3, particularly at the orthosteric binding site. Given that inhibition of mGluR3 has been implicated in undesired effects, we sought to identify selective mGluR2 negative allosteric modulators. Herein we describe the discovery of the highly potent and selective class of mGluR2 negative allosteric modulators, 4-arylquinoline-2-carboxamides, following a successful HTS campaign and medicinal chemistry optimization, showing potent in vivo efficacy in rodent.

Dexmedetomidine enhances ropivacaine-induced sciatic nerve injury in diabetic rats.

BACKGROUND: Previous studies suggest that dexmedetomidine has a protective effect against local anaesthetic-induced nerve injury in regional nerve blocks. Whether this potentially protective effect exists in the context of diabetes mellitus is unknown. METHODS: A diabetic state was established in adult male Sprague-Dawley rats with intraperitoneal injection of streptozotocin. Injections of ropivacaine 0.5%, dexmedetomidine 20 µg kg-1 (alone and in combination), or normal saline (all in 0.2 ml) were made around the sciatic nerve in control and diabetic rats (n=8 per group). The duration of sensory and motor nerve block and the motor nerve conduction velocity (MNCV) were determined. Sciatic nerves were harvested at post-injection day 7 and assessed with light and electron microscopy or used for pro-inflammatory cytokine measurements. RESULTS: Ropivacaine and dexmedetomidine alone or in combination did not produce nerve fibre damage in control non-diabetic rats. In diabetic rats, ropivacaine induced significant nerve fibre damage, which was enhanced by dexmedetomidine. This manifested with slowed MNCV, decreased axon density, and decreased ratio of inner to outer diameter of the myelin sheath (G ratio). Demyelination, axon disappearance, and empty vacuoles were also found using electron microscopy. An associated increase in nerve interleukin-1ß and tumour necrosis factor-α was also seen. CONCLUSIONS: Ropivacaine 0.5% causes significant sciatic nerve injury in diabetic rats that is greatly potentiated by high-dose dexmedetomidine. Although the dose of dexmedetomidine used in this study is considerably higher than that used in clinical practice, our data suggest that further studies to assess ropivacaine (alone and in combination with dexmedetomidine) use for peripheral nerve blockade in diabetic patients are warranted.

Search for multifunctional agents against Alzheimer's disease among non-imidazole histamine H3 receptor ligands. In vitro and in vivo pharmacological evaluation and computational studies of piperazine derivatives.

In the search for new treatments for complex disorders such as Alzheimer's disease the Multi-Target-Directed Ligands represent a very promising approach. The aim of the present study was to identify multifunctional compounds among several series of non-imidazole histamine H3 receptor ligands, derivatives of 1-[2-thiazol-5-yl-(2-aminoethyl)]-4-n-propylpiperazine, 1-[2-thiazol-4-yl-(2-aminoethyl)]-4-n-propylpiperazine and 1-phenoxyalkyl-4-(amino)alkylopiperazine using in vitro and in vivo pharmacological evaluation and computational studies. Performed in vitro assays showed moderate potency of tested compounds against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Molecular modeling studies have revealed possible interactions between the active compounds and both AChE and BuChE as well as the human H3 histamine receptor. Computational studies showed the high drug-likeness of selected compounds with very good physicochemical profiles. The parallel artificial membrane permeation assay proved outstanding blood-brain barrier penetration in test conditions. The most promising compound, A12, chemically methyl(4-phenylbutyl){2-[2-(4-propylpiperazin-1-yl)-1,3-thiazol-5-yl]ethyl}amine, possesses good balanced multifunctional profile with potency toward studied targets - H3 antagonist activity (pA2 = 8.27), inhibitory activity against both AChE (IC50 = 13.96 µM), and BuChE (IC50 = 14.62 µM). The in vivo pharmacological studies revealed the anti-amnestic properties of compound A12 in the passive avoidance test on mice.

Development of pyrazole and spiropyrazoline analogs as multifunctional agents for treatment of Alzheimer's disease.

Cholinergic hypothesis of Alzheimer's disease has been advocated as an essential tool in the last couple of decades for the drug development. Here in, we report de novo fragment growing strategy for the design of novel 3,5-diarylpyrazoles and hit optimization of spiropyrazoline derivatives as acetyl cholinesterase inhibitors. Both type of scaffolds numbering forty compounds were synthesized and evaluated for their potencies against AChE, BuChE and PAMPA. Introduction of lipophilic cyclohexane ring in 3,5-diarylpyrazole analogs led to spiropyrazoline derivatives, which facilitated and improved the potencies. Compound 44 (AChE = 1.937 ±â€¯0.066 µM; BuChE = 1.166 ±â€¯0.088 µM; hAChE = 1.758 ±â€¯0.095 µM; Pe = 9.491 ±â€¯0.34 × 10-6 cm s1) showed positive results, which on further optimization led to the development of compound 67 (AChE = 0.464 ±â€¯0.166 µM; BuChE = 0.754 ±â€¯0.121 µM; hAChE = 0.472 ±â€¯0.042 µM; Pe = 13.92 ±â€¯0.022 × 10-6 cm s1). Compounds 44 and 67 produced significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE. They were found to be safer to MC65 cells and decreased metal induced Aß1-42 aggregation. Further, in-vivo behavioral studies, on scopolamine induced amnesia model, the compounds resulted in better percentage spontaneous alternation scores and were safe, had no influence on locomotion in tested animal groups at dose of 3 mg/kg. Early pharmacokinetic assessment of optimized hit molecules was supportive for further drug development.

Transcriptional co-repressor SIN3A silencing rescues decline in memory consolidation during scopolamine-induced amnesia.

Epigenetic modifications through methylation of DNA and acetylation of histones modulate neuronal gene expression and regulate long-term memory. Earlier we demonstrated that scopolamine-induced decrease in memory consolidation is correlated with enhanced expression of hippocampal DNA methyltransferase 1 (DNMT1) and histone deacetylase 2 (HDAC2) in mice. DNMT1 and HDAC2 act together by recruiting a co-repressor complex and deacetylating the chromatin. The catalytic activity of HDACs is mainly dependent on its incorporation into multiprotein co-repressor complexes, among which SIN3A-HDAC2 co-repressor is widely studied to regulate synaptic plasticity. However, the involvement of co-repressor complex in regulating memory loss or amnesia is unexplored. This study examines the role of co-repressor SIN3A in scopolamine-induced amnesia through epigenetic changes in the hippocampus. Scopolamine treatment remarkably enhanced hippocampal SIN3A expression in mice. To prevent such increase in SIN3A expression, we used hippocampal infusion of SIN3A-siRNA and assessed the effect of SIN3A silencing on scopolamine-induced amnesia. Silencing of SIN3A in amnesic mice reduced the binding of HDAC2 at neuronal immediate early genes (IEGs) promoter, but did not change the expression of HDAC2. Furthermore, it increased acetylation of H3K9 and H3K14 at neuronal IEGs (Arc, Egr1, Homer1 and Narp) promoter, prevented scopolamine-induced down-regulation of IEGs and improved consolidation of memory during novel object recognition task. These findings together suggest that SIN3A has a critical role in regulation of synaptic plasticity and might act as a potential therapeutic target to rescue memory decline during amnesia and other neuropsychiatric pathologies.

Prolonged Duration Local Anesthesia Using Liposomal Bupivacaine Combined With Liposomal Dexamethasone and Dexmedetomidine.

BACKGROUND: The relatively short duration of effect of local anesthetics has been addressed by encapsulation in drug delivery systems. Codelivery with a single compound that produces an adjuvant effect on nerve block but without intrinsic local anesthetic properties can further prolong the nerve block effect. Here, we investigated whether codelivery of more than 1 encapsulated adjuvant compound can further enhance nerve blockade. METHODS: Liposomes loaded with bupivacaine (Bup), dexamethasone phosphate (DexP), or dexmedetomidine (DMED) were synthesized and its in vitro drug release profiles were determined. Animals (Sprague-Dawley rats) were injected with liposomal Bup (Lipo-Bup) and adjuvants at the sciatic nerve and underwent a modified hot plate test to assess the degree of nerve block. The duration of block was monitored and the tissue reaction was assessed. RESULTS: Coinjection of Lipo-Bup with liposomal DexP (Lipo-DexP) and liposomal DMED (Lipo-DMED) prolonged the duration of sciatic nerve block 2.9-fold compared to Lipo-Bup alone (95% confidence interval, 1.9- to 3.9-fold). The duration of the block using this combination was significantly increased to 16.2 ± 3.5 hours compared to Lipo-Bup with a single liposomal adjuvant (8.7 ± 2.4 hours with Lipo-DMED, P = .006 and 9.9 ± 5.9 hours with Lipo-DexP, P = .008). The coinjection of Lipo-Bup with liposomal adjuvants decreased tissue inflammation (P = .014) but did not have a significant effect on myotoxicity when compared to Lipo-Bup alone. Coinjection of Lipo-Bup with unencapsulated adjuvants prolonged the duration of nerve block as well (25.0 ± 6.3 hours; P < .001) however was accompanied by systemic side effects. CONCLUSIONS: Codelivery of Lipo-DexP and Lipo-DMED enhanced the efficacy of Lipo-Bup. This benefit was also seen with codelivery of both adjuvant molecules in the unencapsulated state, but with marked systemic toxicity.

Profiling of hepatic metabolizing enzymes and nuclear receptors in rats with adjuvant arthritis by targeted proteomics.

Inflammatory conditions alter the expression and activity of factors influencing pharmacokinetics, such as metabolizing enzymes. The study examined alterations of hepatic protein levels of cytochrome P450 (CYP), UDP-glucuronosyltransferase (UGT) and nuclear receptors in rats with adjuvant-induced arthritis (AA rats), an inflammatory animal model, by liquid chromatography-tandem mass spectrometry-based targeted proteomics. The protein levels of CYP1A1, CYP1A2, CYP2A1, CYP2A3, CYP2C6, CYP2C12, CYP2D3, CYP2E1, CYP3A9, UGT1A1 and UGT1A2/3 in liver microsomes of AA rats were significantly lower than those in control rats. The protein levels of constitutive androstane receptor (CAR) and retinoid X receptor α (RXRα) in the cytoplasm and nucleus were also significantly decreased, to approximately 60% of the control levels. The decreased protein levels of CYP1A2, CYP2C6, CYP2D3, CYP2E1 and UGT1A1 were potentially associated with downregulation of CAR or RXRα expression in the nucleus.

The effects of gabapentin on acute opioid tolerance to remifentanil under sevoflurane anesthesia in rats.

BACKGROUND: Tolerance to remifentanil during sevoflurane anesthesia may blunt the ability of this drug to reduce anesthetic requirements. Gabapentin has been shown to be effective in reducing postoperative narcotic usage, a reduction that may be associated with a reduction in opioid-induced tolerance and hyperalgesia. We sought to determine whether gabapentin might prevent the observed acute opioid tolerance (AOT) produced by remifentanil in sevoflurane minimum alveolar concentration (MAC). METHODS: Wistar rats were anesthetized with sevoflurane and the effects of gabapentin alone on sevoflurane MAC were determined at doses of 150 and 300 mg · kg(-1). In a second experiment, gabapentin 300 mg · kg(-1) was administered before remifentanil (120 and 240 µg · kg(-1) · h(-1)). The MAC was determined before gabapentin administration and 3 more times at 1.5-hour intervals after drug administration to assess AOT. MAC was determined from intratracheal gas samples using a sidestream gas analyzer; tail clamping was used as a supramaximal stimulus. Statistical analysis was performed with the 1-way analysis of variance test. RESULTS: Remifentanil reduced MAC (2.5 ± 0.2%) by 16% ± 5% and 36% ± 6% (120 and 240 µg · kg(-1) · h(-1), respectively, P < 0.01) with a further reduction produced by coadministration with gabapentin 300 mg · kg(-1) to 39% ± 12% and 62% ± 14%, respectively (P < 0.01 versus remifentanil alone). Gabapentin given alone at 150 and 300 mg · kg(-1) reduced MAC by 26% (both doses, P < 0.01). AOT was observed with remifentanil and characterized by a lower degree of MAC reduction, approximately 1.5 hours later (P < 0.05). However, when remifentanil was administered with gabapentin, the AOT to remifentanil was not observed (P > 0.05). CONCLUSIONS: Gabapentin reduced the sevoflurane MAC and enhanced the MAC reduction produced by remifentanil. This enhancement may limit AOT in rats.

Comparison of N-methyl-2-pyrrolidone (NMP) and the "date rape" drug GHB: behavioral toxicology in the mouse model.

N-methyl-2-pyrrolidone (NMP) and γ-hydroxybutyrate acid (GHB) are synthetic solvents detected in the recreational drug market. GHB has sedative/hypnotic properties and is used for criminal purposes to compromise reaction ability and commit drug-facilitated sexual assaults and other crimes. NMP is a strong solubilizing solvent that has been used alone or mixed with GHB in case of abuse and robberies. The aim of this experimental study is to compare the acute pharmaco-toxicological effects of NMP and GHB on neurological signs (myoclonia, convulsions), sensorimotor (visual, acoustic, and overall tactile) responses, righting reflex, thermoregulation, and motor activity (bar, drag, and accelerod test) in CD-1 male mice. Moreover, since cardiorespiratory depression is one of the main adverse effects related to GHB intake, we investigated the effect of NMP and GHB on cardiorespiratory changes (heart rate, breath rate, oxygen saturation, and pulse distension) in mice. The present study demonstrates that NMP inhibited sensorimotor and motor responses and induced cardiorespiratory depression, with a lower potency and efficacy compared to GHB. These results suggest that NMP can hardly be used alone as a substance to perpetrate sexual assault or robberies.

Protective effects of vitamin D on learning and memory deficit induced by scopolamine in male rats: the roles of brain-derived neurotrophic factor and oxidative stress.

The beneficial effects of vitamin D (vit D) on central nervous system disorders have been suggested. In the current research, the protective effects of vit D on learning and memory deficit induced by scopolamine, oxidative stress criteria, brain-derived neurotrophic factor (BDNF), and nitric oxide (NO) in the brain were investigated. Rats were divided into five groups, including (1) Control, (2) Scopolamine (2 mg/kg), (3-5) Scopolamine + Vit D (100, 1000, and 10,000 IU/kg) groups. Vit D administrated for 2 weeks and in the third week scopolamine co-administrated with vit D and behavioral tests, including Morris water maze (MWM) and passive avoidance (PA) tests, were carried out. The cortical and hippocampal tissues were analyzed for BDNF, catalase (CAT), and superoxide dismutase (SOD) activities, thiol content, NO metabolites, and malondialdehyde (MDA) concentration. Scopolamine injection significantly impaired rats' performance on the MWM and PA test. It further enhanced the MDA and nitrite level while decreased thiol content and BDNF levels and SOD and CAT activities in the brain. Administration of both 1000 and 10,000 IU/kg vit D improved cognitive outcome in MWM and PA tests. In addition, vit D elevated thiol content, SOD and CAT activities, and BDNF levels, while reduced nitrite and MDA concentration. Vit D also increased the levels of vit D and calcium in the serum. The results demonstrated that vit D has protective effects on scopolamine-associated learning and memory impairment by improving BDNF levels and attenuating NO and brain tissue oxidative damage.

Lacidipine Prevents Scopolamine-Induced Memory Impairment by Reducing Brain Oxido-nitrosative Stress in Mice.

Cholinergic deficits and oxido-nitrosative stress are consistently associated with Alzheimer's disease (AD). Previous findings indicate that acetylcholine subdues Ca2+ current in the brain. Cholinergic antagonists (e.g., scopolamine) can instigate Ca2+-induced redox imbalance, inflammation, and cell-death pathways leading to AD-type memory impairment. Earlier, several Ca2+-channel blockers (CCB, e.g., dihydropyridine type) or cholinergic enhancers showed promising results in animal models of AD. In the present research, pretreatment effects of lacidipine (L-type CCB) on learning and memory functions were investigated using the scopolamine mouse model of AD. Swiss albino mice (20-25 g) were administered lacidipine (1 and 3 mg/kg) for 14 days. Scopolamine, an anti-muscarinic drug, was given (1 mg/kg) from days 8 to 14. The mice were subjected to elevated plus maze (EPM) and passive-avoidance (PA) paradigms. Bay-K8644 (a Ca2+-channel agonist) was administered before behavioral studies on days 13 and 14. Biochemical parameters of oxidative stress and acetylcholinesterase (AChE) activity were quantified using the whole brain. Behavioral studies showed an increase in transfer latency (TL) in the EPM test and a decrease in step-through latency (STL) in the PA test in scopolamine-administered mice. Scopolamine enhanced the AChE activity and oxidative stress in the brain of mice which resulted in memory impairment. Lacidipine prevented the amnesia against scopolamine and reduced the oxidative stress and AChE activity in the brain of mice. Bay-K8644 attenuated the lacidipine-induced improvement in memory and redox balance in scopolamine-administered mice. Lacidipine can prevent the oxidative stress and improve the cholinergic function in the brain. These properties of lacidipine can mitigate the pathogenesis of AD-type dementia.

Comparison of thiopental, urethane, and pentobarbital in the study of experimental cardiology in rats in vivo.

BACKGROUND: Despite earlier research studying the influence of anesthetics in arrhythmia models, a lot of controversy remains. The aim was to compare the influence of three anesthetics (60 mg/kg thiopental, 1200 mg/kg urethane, 60 mg/kg pentobarbital intraperitoneally) on ventricular arrhythmias and to combine it with measured hemodynamic parameters to find the most suitable agent for such experiments. METHOD: In the model of ischemia- and reperfusion-induced arrhythmias in Sprague-Dawley rats, after left anterior descending coronary artery occlusion (7 minutes) and reperfusion (15 minutes), the following parameters have been measured or calculated: mortality index; ventricular fibrillation and tachycardia incidence and duration; systolic, diastolic, and mean arterial blood pressure; heart rate; myocardial index of oxygen consumption; and plasma creatine kinase concentration. RESULTS: Evident depressive action of urethane on heart rate, blood pressures, and myocardial index of oxygen consumption should be reason enough to exclude it from use in such studies. Pentobarbital had no effect on arrhythmias, whereas thiopental was antiarrhythmic. CONCLUSIONS: Pentobarbital is the most suitable anesthetic offering stable hemodynamic values during arrhythmia studies. These hemodynamic values, which were similar to physiological values in awake rats, the long arrhythmia duration during reperfusion and approximately 50% mortality index are crucial parameters for evaluating antiarrhythmic drugs.

Suspected acute meperidine toxicity in a dog.

OBSERVATIONS: A 22-month-old male neutered Coton De Tulear dog was presented for upper gastrointestinal endoscopy under general anesthesia. The anesthetic plan included premedication with intramuscular meperidine (4 mg kg(-1)) but meperidine was inadvertently administered at ten-fold this dose. Within 5 minutes, the dog was unresponsive to external stimulation, and by 10 minutes post-injection developed generalized signs of central nervous system (CNS) excitement. Initial therapy included inspired oxygen supplementation, and single intravenous (IV) doses of diazepam (0.68 mg kg(-1)) and naloxone (0.03 mg kg(-1)) to no effect. A second dose of diazepam (0.46 mg kg(-1), IV) abolished most of the signs of CNS excitement. General anesthesia was induced and the endoscopy performed. Time to extubation was initially prolonged, but administering naloxone (final dose 0.1 mg kg(-1), IV) to effect enabled extubation. After naloxone, the dog became agitated, noise sensitive, and had leg and trunk muscle twitches. Diazepam (0.30 mg kg(-1), IV) abolished these signs and the dog became heavily sedated and laterally recumbent. Naloxone administration was continued as a constant rate infusion (0.02 mg kg(-1) hour(-1), IV) until approximately 280 minutes post-meperidine injection, at which time the dog suddenly sat up. Occasional twitches of the leg and trunk muscles were observed during the night. The dog was discharged the next day appearing clinically normal. CONCLUSIONS: Given that the CNS excitatory effects of normeperidine are not a mu opioid receptor effect, the use of naloxone should be considered carefully when normeperidine excitotoxicity is suspected. Benzodiazepines may be beneficial in ameliorating clinical signs of normeperidine excitotoxicity.

Additives in intravenous anesthesia modulate pulmonary inflammation in a model of LPS-induced respiratory distress.

BACKGROUND: It has been suggested that propofol with ethylenediaminetetraacetic acid (EDTA) can modulate the systemic inflammatory response. Prolonged higher levels of pulmonary inflammation are associated with poor outcome of patients with acute lung injury. In the present study, we hypothesized that pulmonary inflammation could be modulated by propofol with EDTA compared with propofol with sulfite. METHODS: Respiratory distress was induced in rats (n=25) by intratracheal nebulization of lipopolysaccharide (LPS). After 24 h, animals were randomized to either propofol with EDTA (Propofol(EDTA)), propofol with sulfite (Propofol(sulfite)) or ketamine/midazolam (Ket/Mid); control animals received saline (n=30). Animals were ventilated for 4 h and blood gases were measured hourly. Bronchoalveolar lavage (BAL) was performed for cytokine analysis of: tumor necrosis factor (TNF), interleukin (IL)-6 and macrophage inflammatory protein (MIP)-2. RESULTS: LPS led to increased pulmonary inflammation in all groups compared with the control groups. Gas exchange deteriorated over time only in the LPS Propofol(sulfite) group and was significantly lower than the Ket/Mid group. Only IL-6 was significantly higher in the LPS Propofol(sulfite) group compared with both the Ket/Mid group and the Propofol(EDTA) group. CONCLUSION: Pulmonary IL-6 can be modulated by additives in systemic anesthesia. IMPLICATION STATEMENT: This study demonstrates that pulmonary inflammation caused by direct lung injury can be modulated by intravenous anesthesia used in critically ill patients.

Use of bulleyaconitine A as an adjuvant for prolonged cutaneous analgesia in the rat.

BACKGROUND: Bulleyaconitine A (BLA) is an analgesic and antiinflammatory drug isolated from Aconitum plants. BLA has several potential targets, including voltage-gated Na+ channels. We tested whether BLA elicited long-lasting cutaneous analgesia, when co-injected with lidocaine and epinephrine, as a model for prolonged infiltration anesthesia. METHODS: The local anesthetic properties of BLA were assessed by the patch-clamp technique in HEK293t cells expressing Nav1.7 and Nav1.8 neuronal Na+ channels, both crucial for nociception. Drug solutions (0.6 mL) were injected subcutaneously via rat shaved dorsal skin. Inhibition of the cutaneous trunci muscle reflex was evaluated by pinpricks. Skin cross-sections were stained with hematoxylin and eosin or with antibodies against PGP9.5. RESULTS: BLA at 10 microM interacted minimally with resting or inactivated Nav1.7 and Nav1.8 Na+ channels when infrequently stimulated to +50 mV for 3 ms. However, when stimulated at 2 Hz for 1000 pulses, their peak Na+ currents were >90% reduced by BLA. This use-dependent inhibition was not significantly reversed after 15-min washing. Complete nociceptive blockade after injection of lidocaine (0.5%)/epinephrine (1:200,000) lasted for approximately 1 h in rats; full recovery occurred after approximately 6 h. Co-injection of 0.125 mM BLA with lidocaine/epinephrine increased the duration of complete nociceptive blockade to 24 h. Full recovery occurred after approximately 6 days. Skin histology including peripheral nerve fibers appeared unaffected by BLA. CONCLUSIONS: BLA inhibits Nav1.7 and Nav1.8 Na+ currents in a use-dependent manner. Co-injection of BLA at

Systematic assessment of gamma hydroxybutyrate (GHB) effects during and after acute intoxication.

We adapted and tested a previously published questionnaire battery eliciting sensory and cognitive symptoms during (acute) and immediately after (post-acute) GHB intoxication. Studying 125 GHB users, we assessed the instrument's internal consistency using Cronbach's alpha (CA) and responsiveness to change comparing acute and post-acute symptoms. The final 14-item battery demonstrated good internal consistency (CA >or= 0.85, both acute and post-acute). The median symptom score (possible range 0-64) was 30 (acute) and 6 (post-acute; difference p < 0.001). This modified substance-specific symptom battery, which is easily administered, demonstrated excellent performance characteristics. It can be used to study GHB and, potentially, related drugs of abuse.

Early Exposure to General Anesthesia Disrupts Spatial Organization of Presynaptic Vesicles in Nerve Terminals of the Developing Rat Subiculum.

Exposure to general anesthesia (GA) during critical stages of brain development induces widespread neuronal apoptosis and causes long-lasting behavioral deficits in numerous animal species. Although several studies have focused on the morphological fate of neurons dying acutely by GA-induced developmental neuroapoptosis, the effects of an early exposure to GA on the surviving synapses remain unclear. The aim of this study is to study whether exposure to GA disrupts the fine regulation of the dynamic spatial organization and trafficking of synaptic vesicles in presynaptic terminals. We exposed postnatal day 7 (PND7) rat pups to a clinically relevant anesthetic combination of midazolam, nitrous oxide, and isoflurane and performed a detailed ultrastructural analysis of the synaptic vesicle architecture at presynaptic terminals in the subiculum of rats at PND 12. In addition to a significant decrease in the density of presynaptic vesicles, we observed a reduction of docked vesicles, as well as a reduction of vesicles located within 100 nm from the active zone, in animals 5 days after an initial exposure to GA. We also found that the synaptic vesicles of animals exposed to GA are located more distally with respect to the plasma membrane than those of sham control animals and that the distance between presynaptic vesicles is increased in GA-exposed animals compared to sham controls. We report that exposure of immature rats to GA during critical stages of brain development causes significant disruption of the strategic topography of presynaptic vesicles within the nerve terminals of the subiculum.

Memory enhancement mediated by the steroid sulfatase inhibitor (p-O-sulfamoyl)-N-tetradecanoyl tyramine.

The intent of this study was to determine whether altering the metabolism of neurosteroids via blockade of the enzyme, steroid sulfatase, could enhance memory retention in rats. The steroid sulfatase inhibitor p-O-(sulfamoyl)-N-tetradecanoyl tyramine (DU-14) was administered alone and in combination with the neurosteroid dehydroepiandrosterone sulfate (DHEAS) to rats which were then tested for the reversal of scopolamine-induced amnesia. A single 30 mg/kg IP dose of DU-14 produced a significant inhibition of steroid sulfatase activity in both brain (14.8%), and liver (85.2%) tissues, 24 hours following administration. In a passive avoidance test, DU-14 enhanced the reversal of amnesia by DHEAS. These results suggest that steroid sulfatase inhibition can potentiate the memory enhancing properties of DHEAS.

Lycium barbarum polysaccharides prevent memory and neurogenesis impairments in scopolamine-treated rats.

Lycium barbarum is used both as a food additive and as a medicinal herb in many countries, and L. barbarum polysaccharides (LBPs), a major cell component, are reported to have a wide range of beneficial effects including neuroprotection, anti-aging and anticancer properties, and immune modulation. The effects of LBPs on neuronal function, neurogenesis, and drug-induced learning and memory deficits have not been assessed. We report the therapeutic effects of LBPs on learning and memory and neurogenesis in scopolamine (SCO)-treated rats. LBPs were administered via gastric perfusion for 2 weeks before the onset of subcutaneous SCO treatment for a further 4 weeks. As expected, SCO impaired performance in novel object and object location recognition tasks, and Morris water maze. However, dual SCO- and LBP-treated rats spent significantly more time exploring the novel object or location in the recognition tasks and had significant shorter escape latency in the water maze. SCO administration led to a decrease in Ki67- or DCX-immunoreactive cells in the dentate gyrus and damage of dendritic development of the new neurons; LBP prevented these SCO-induced reductions in cell proliferation and neuroblast differentiation. LBP also protected SCO-induced loss of neuronal processes in DCX-immunoreactive neurons. Biochemical investigation indicated that LBP decreased the SCO-induced oxidative stress in hippocampus and reversed the ratio Bax/Bcl-2 that exhibited increase after SCO treatment. However, decrease of BDNF and increase of AChE induced by SCO showed no response to LBP administration. These results suggest that LBPs can prevent SCO-induced cognitive and memory deficits and reductions in cell proliferation and neuroblast differentiation. Suppression of oxidative stress and apoptosis may be involved in the above effects of LBPs that may be a promising candidate to restore memory functions and neurogenesis.