Comparative effects of levobupivacaine and racemic bupivacaine on excitotoxic neuronal death in culture and N-methyl-d-aspartate-induced seizures in mice

Ultrasound-guided Bilateral Erector Spinae Plane Block for Postoperative Analgesia in Laparoscopic Cholecystectomy: A Randomized Controlled Trial

BACKGROUND

Laparoscopic cholecystectomy (LC) is associated with moderate-to-severe pain in immediate postoperative period. Some patients even suffer from prolonged pain long after surgery.

AIMS

The aim of present study is to determine the efficacy of ultrasound-guided bilateral erector spinae plane block (ESPB) in patients undergoing LC, time to ambulation after surgery, and incidence of prolonged pain up to 6 months later.

SETTINGS AND DESIGN

This was a double-blinded prospective randomized controlled trial.

MATERIALS AND METHODS

Eighty-five adults posted for elective LC were randomized to receive bilateral ESPB at T7 level with either 20 mL of 0.375% ropivacaine or 20 mL normal saline. Postoperative static and dynamic pain score as per the visual analog scale (VAS), intraoperative requirement of fentanyl, postoperative use of diclofenac, time to ambulation after surgery, and presence of any pain after surgery were noted.

STATISTICAL ANALYSIS

Independent t-test and Mann-Whitney U-test were used for quantitative data, while Chi-square test was used for comparing qualitative data.

RESULTS

Static and dynamic VAS scores were significantly lower in ESPB group (P < 0.05). Intraoperative fentanyl requirement (165 ± 30.72 - ESPB, 180.95 ± 29.12 - controls, P = 0.020) and number of patients requiring diclofenac (28/42 - ESPB, 37/42 - controls, P = 0.019) were lower, while number of patients ambulating by 4 hours (20/42 - ESPB, 9/42 - control, P = 0.012) were higher in ESPB group. Patients suffering from pain at 1 week (22/42 - ESPB and 34/42 - control, P = 0.005) and 1 month (9/42 - ESPB and 13/42 - control, P = 0.207) were lower in ESPB group.

CONCLUSION

ESPB provides effective analgesia and early ambulation after LC. The benefit extends to 1 week thereafter.

Role of Phosphatidylinositol-3 Kinase Pathway in NMDA Preconditioning: Different Mechanisms for Seizures and Hippocampal Neuronal Degeneration Induced by Quinolinic Acid

N-methyl D-aspartate (NMDA) preconditioning is evoked by the administration of a subtoxic dose of NMDA and is protective against neuronal excitotoxicity. This effect may involve a diversity of targets and cell signaling cascades associated to neuroprotection. Phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt) and mitogen-activated protein kinases (MAPKs) such as extracellular regulated protein kinase 1/2 (ERK1/2) and p38^MAPK pathways play a major role in neuroprotective mechanisms. However, their involvement in NMDA preconditioning was not yet fully investigated. The present study aimed to evaluate the effect of NMDA preconditioning on PI3K/Akt, ERK1/2, and p38^MAPK pathways in the hippocampus of mice and characterize the involvement of PI3K on NMDA preconditioning-evoked prevention of seizures and hippocampal cell damage induced by quinolinic acid (QA). Thus, mice received wortmannin (a PI3K inhibitor) and 15 min later a subconvulsant dose of NMDA (preconditioning) or saline. After 24 h of this treatment, an intracerebroventricular QA infusion was administered. Phosphorylation levels and total content of Akt, glycogen synthase protein kinase-3β (GSK-3β), ERK1/2, and p38^MAPK were not altered after 24 h of NMDA preconditioning with or without wortmmanin pretreatment. Moreover, after QA administration, behavioral seizures, hippocampal neuronal degeneration, and Akt activation were evaluated. Inhibition of PI3K pathway was effective in abolishing the protective effect of NMDA preconditioning against QA-induced seizures, but did not modify neuronal protection promoted by preconditioning as evaluated by Fluoro-Jade B staining. The study confirms that PI3K participates in the mechanism of protection induced by NMDA preconditioning against QA-induced seizures. Conversely, NMDA preconditioning-evoked protection against neuronal degeneration is not altered by PI3K signaling pathway inhibition. These results point to differential mechanisms regarding protection against a behavioral and cellular manifestation of neural damage.

Evaluation of the effects of ketamine on spinal anesthesia with levobupivacaine or ropivacaine

Spinal anesthesia or regional anesthesia is a potent anesthetic procedure. Additional modalities have been sought to increase the duration of block in spinal anesthesia. Ketamine is an N-methyl-D-aspartate (NMDA) receptor blocker that has an anesthetic effect when injected intrathecally and has a synergic effect with bupivacaine. Ketamine also has potent analgesic properties. The present study investigated the effect of intrathecally administered ketamine on spinal anesthesia with levobupivacaine or ropivacaine. Sprague-Dawley rats at post-natal day 21 were exposed to spinal anesthesia with 0.5% levobupivacaine or 0.5% ropivacaine. Separate groups of rats were treated with intrathecal ketamine at a 5 or 10 mg/kg bodyweight dose along with ropivacaine or levobupivacaine. The thermal and mechanical withdrawal latencies of the animals were determined using hot plate and von Frey filaments, respectively. A rotarod apparatus was employed to assess the capacity of the rats to rotate the spindle at 24 h following anesthesia. The gait of the rat pups was also assessed. Intrathecal administration of ketamine resulted in dense blocks and extended the duration of spinal blocks as evidenced by thermal latencies and responses to von Frey filaments. The latency to fall was shorter in rats exposed to ketamine along with ropivacaine or levobupivacaine spinal anesthesia. The gait parameters were also more disturbed upon ketamine administration. In conclusion, ketamine administration with ropivacaine or levobupivacaine increased the intensity and duration of spinal blockade, thereby increasing the anesthetic effects.

EEG Radiotelemetry in Small Laboratory Rodents: A Powerful State-of-the Art Approach in Neuropsychiatric, Neurodegenerative, and Epilepsy Research

EEG radiotelemetry plays an important role in the neurological characterization of transgenic mouse models of neuropsychiatric and neurodegenerative diseases as well as epilepsies providing valuable insights into underlying pathophysiological mechanisms and thereby facilitating the development of new translational approaches. We elaborate on the major advantages of nonrestraining EEG radiotelemetry in contrast to restraining procedures such as tethered systems or jacket systems containing recorders. Whereas a main disadvantage of the latter is their unphysiological, restraining character, telemetric EEG recording overcomes these disadvantages. It allows precise and highly sensitive measurement under various physiological and pathophysiological conditions. Here we present a detailed description of a straightforward successful, quick, and efficient technique for intraperitoneal as well as subcutaneous pouch implantation of a standard radiofrequency transmitter in mice and rats. We further present computerized 3D-stereotaxic placement of both epidural and deep intracerebral electrodes. Preoperative preparation of mice and rats, suitable anaesthesia, and postoperative treatment and pain management are described in detail. A special focus is on fields of application, technical and experimental pitfalls, and technical connections of commercially available radiotelemetry systems with other electrophysiological setups.

Aloysia gratissima prevents cellular damage induced by glutamatergic excitotoxicity

Objectives

Aloysia gratissima aqueous extract (AE) was investigated as a putative protective agent against quinolinic acid (QA)-induced seizures in mice and hippocampal cell damage. Additionally, AE and ferulic acid (FA), the major compound of AE, were tested against neurotoxicity evoked by glutamate or its N-methyl-D-aspartate receptor (NMDAR) agonist, QA on hippocampal slices, in vitro.

Methods

Mice were treated with AE before QA infusion (36.8 nmol/site) and seizures were analysed. Cellular viability and modulation of excitatory amino acid transport were verified in hippocampal slices. In-vitro AE or FA was tested against neurotoxicity induced by glutamate or QA.

Key findings

AE did not prevent QA-induced seizures; however, it prevented cellular death and disruption of excitatory amino acid transport. In-vitro AE (0.1 or 1.0 mg/ml) or FA (1 or 10 μm), improved cell viability against citotoxicity exerted by glutamate or QA, respectively. Both AE and FA have protective effects depending on activation of the phosphatidylinositol-3 kinase (PI3K) signalling pathway.

Conclusions

AE attenuated QA-induced cell damage possibly involving the glutamate transport modulation through NMDAR interaction. FA shows a similar profile of neuroprotection promoted by AE. Therefore, AE treatment might be a useful strategy in preventing brain damage caused by exacerbation of glutamatergic toxicity in nervous system disorders.

Comparative study related to cardiovascular safety between bupivacaine (S75-R25) and ropivacaine in brachial plexus block

BACKGROUND AND OBJECTIVES

Bupivacaine is a first choice for regional anesthesia considering its effectiveness, long duration and less motor blockade. Bupivacaine (S75-R25) is a mixture of optical isomers containing 75% levobupivacaine (S-) and 25% dextrobupivacaine (R+) created by a Brazilian pharmaceutical company. This investigation compared cardiac safety and efficacy of bupivacaine S75-R25 with vasoconstrictor and ropivacaine for brachial plexus blockade.

METHODS

Patients were randomized to receive brachial plexus anesthesia with either bupivacaine S75-R25 with epinephrine 1:200,000 (bupi) or ropivacaine (ropi), both at 0.50%, in 30 mL solution. We registered a continuous Holter ECG throughout the procedure, as well as the Lovett scale of force in addition to monitoring (heart rate, pulse oximetry and non-invasive blood pressure). The incidence of adverse events was compared with the chi-square or Fisher test.

RESULTS

We allocated forty-four patients into two groups. They did not show any difference related to age, weight or height, gender, as well as for surgical duration. Supraventricular arrhythmias were not different before or after the plexus blockade, independent of the local anesthetic chosen. Loss of sensitivity was faster for the bupivacaine group (23.1 ± 11.7 min) compared to the ropivacaine one (26.8 ± 11.5 min), though not significant (p = 0.205, Student t). There was a reduction in the cardiac rate, observed during the twenty-four-hour Holter monitoring.

CONCLUSIONS

This study showed similar efficacy between bupivacaine S75-R25 for brachial plexus blockade and ropivacaine, with similar incidences of supraventricular arrhythmias.

Comparative study related to cardiovascular safety between bupivacaine (S75-R25) and ropivacaine in brachial plexus block

BACKGROUND AND OBJECTIVES

Bupivacaine is a fi rst choice for regional anesthesia considering its effectiveness, long duration and less motor blockade. Bupivacaine (S75-R25) is a mixture of optical isomers containing 75% levobupivacaine (S-) and 25% dextrobupivacaine (R+) created by a Brazilian pharmaceutical company. This investigation compared cardiac safety and efficacy of bupivacaine S75-R25 with vasoconstrictor and ropivacaine for brachial plexus blockade.

METHODS

Patients were randomized to receive brachial plexus anesthesia with either bupivacaine S75-R25 with epinephrine 1:200,000 (bupi) or ropivacaine (ropi), both at 0.50%, in 30 mL solution.We registered a continuous Holter ECG throughout the procedure, as well as the Lovett scale of force in addition to monitoring (heart rate, pulse oximetry and non-invasive blood pressure). The incidence of adverse events was compared with the chi-square or Fisher test.

RESULTS

We allocated forty-four patients into two groups. They did not show any difference related to age, weight or height, gender, as well as for surgical duration. Supraventricular arrhythmias were not different before or after the plexus blockade, independent of the local anestheticchosen. Loss of sensitivity was faster for the bupivacaine group (23.1 ± 11.7 min) compared to the ropivacaine one (26.8 ± 11.5 min), though not significant (p = 0.205, Student t). There was a reduction in the cardiac rate, observed during the twenty-four-hour Holter monitoring.

CONCLUSIONS

This study showed similar efficacy between bupivacaine S75-R25 for brachial plexus blockade and ropivacaine, with similar incidences of supraventricular arrhythmias.

NMDA preconditioning attenuates cortical and hippocampal seizures induced by intracerebroventricular quinolinic acid infusion

Searching for new therapeutic strategies through modulation of glutamatergic transmission using effective neuroprotective agents is essential. Glutamatergic excitotoxicity is a common factor to neurodegenerative diseases and acute events such as cerebral ischemia, traumatic brain injury, and epilepsy. This study aimed to evaluate behavioral and electroencephalographic (EEG) responses of mice cerebral cortex and hippocampus to subconvulsant and convulsant application of NMDA and quinolinic acid (QA), respectively. Moreover, it aimed to evaluate if EEG responses may be related to the neuroprotective effects of NMDA. Mice were preconditioned with NMDA (75 mg/kg, i.p.) and EEG recordings were performed for 30 min. One day later, QA was injected (36.8 nmol/site) and EEG recordings were performed during 10 min. EEG analysis demonstrated NMDA preconditioning promotes spike-wave discharges (SWDs), but it does not display behavioral manifestation of seizures. Animals that were protected by NMDA preconditioning against QA-induced behavioral seizures, presented higher number of SWD after NMDA administration, in comparison to animals preconditioned with NMDA that did display behavioral seizures after QA infusion. No differences were observed in latency for the first seizure or duration of seizures. EEG recordings after QA infusion demonstrated there were no differences in the number of SWD, latency for the first seizure or duration of seizures in animals pretreated with saline or in animals preconditioned by NMDA that received QA. A negative correlation was identified between the number of NMDA-induced SWD and QA-induced seizures severity. These results suggest a higher activation during NMDA preconditioning diminishes mice probability to display behavioral seizures after QA infusion.

Lipophilicity but not stereospecificity is a major determinant of local anaesthetic-induced cytotoxicity in human T-lymphoma cells

BACKGROUND AND OBJECTIVES

Local neurotoxicity of local anaesthetics is a well known phenomenon which is determined by lipophilicity. Recent reports have indicated the relevance of local anaesthetic-induced cytotoxicity also in nonneuronal tissues. This study re-evaluates the role of lipophilicity in local anaesthetic cytotoxicity in nonneuronal cells. In addition, the toxicities of pipecoloxylidine S(-) enantiomers were investigated.

METHODS

Local anaesthetic-induced cytotoxicity was investigated in vitro in T-lymphoma cells (Jurkat). Cells were incubated with each of eight different local anaesthetics, two esters and six amides. Annexin V-fluorescein isothiocyanate and 7-aminoactinomycin D double staining followed by flow cytometry were used to investigate the fraction of early apoptotic cells as well as the overall cell death. The concentrations leading to 50% cell death (LC50) were calculated and compared. In a second step, we compared the toxicities of S(-) bupivacaine and the racemate as well as R(+) and S(-) ropivacaine.

RESULTS

Concentration-dependent cytotoxicity was observed for all investigated local anaesthetics. Apoptosis was seen at low concentrations, whereas necrosis was observed at higher concentrations. LC50 values of the different local anaesthetics yielded the following decreasing order of toxicity: tetracaine, bupivacaine, ropivacaine, prilocaine, procaine, lidocaine, articaine and mepivacaine. Toxicity correlated with octanol/buffer partition coefficients, but was independent of the ester or amide linkage. There was no effect of stereoisomerism on apoptosis and necrosis.

CONCLUSION

Moderate correlations for cytotoxicity with lipophilicity and clinical potency of local anaesthetics can be found in nonneuronal cells that are less than those reported previously with neuronal cells. Structural factors such as ester or amide linkage or stereospecificity do not have any influence on cytotoxicity. Although S(-) enantiomers may be advantageous with regard to systemic toxicity, they have no advantage in respect of local cytotoxicity in vitro.

Long-acting local anesthetics and perioperative pain management

Although the use of long-acting local anesthetics has become a useful therapeutic approach for managing peri- and postoperative pain, recent evidence reveals unexpected outcomes. This article reviews the clinical use of long-acting local anesthetics, presents current clinical research findings, and makes recommendations for their use.

Transient neurological symptoms after spinal anaesthesia with levobupivacaine 5 mg/ml or lidocaine 20 mg/ml

BACKGROUND

Transient neurological symptoms (TNS) after spinal anaesthesia have been reported most commonly in association with lidocaine, but have been observed with other local anaesthetics. The aim of this prospective, randomized, double-blind study was to investigate the incidence of TNS after spinal anaesthesia with either levobupivacaine or lidocaine.

METHODS

Patients undergoing inguinal hernia, appendectomy, varicose vein or minor orthopaedic operations were included in the study (60 patients; 47 male, 13 female, overall mean age 30 years). All patients had an American Society of Anesthesiologists score of I or II. The patients were randomly assigned to receive spinal anaesthesia with either 20 mg isobaric levobupivacaine (5 mg/ml) or 80 mg isobaric lidocaine (20 mg/ml). Onset of sensory and motor block and side effects were recorded. On post-operative days 1, 2, and 3, patients were interviewed by an investigator blinded to the spinal anaesthetic used. The patients were classified as having TNS if, following recovery from anaesthesia, there was pain in the buttocks, thighs and/or lower limbs.

RESULTS

In the levobupivacaine group, one patient (3.33%) experienced TNS, whereas in the lidocaine group, eight (26.6%) experienced TNS (P=0.002). Maximum times to arrival of sensory blocks were shorter with lidocaine (P<0.001). The levobupivacaine and lidocaine groups did not differ significantly in terms of the highest dermatome included in sensory block or motor block grade.

CONCLUSION

After spinal anaesthesia with levobupivacaine, the incidence of TNS was much less than after lidocaine. However, it appears that TNS may occur in association with levobupivacaine.

Hippocampal Seizure Resistance and Reduced Neuronal Excitotoxicity in Mice Lacking the Cav2.3 E/R-Type Voltage-Gated Calcium Channel

Voltage-gated calcium channels are key components in the etiology and pathogenesis of epilepsies. Former studies mainly focused on P/Q-type Cav2.1 and T-type Cav3.2 Ca2+ channels involved in absence epileptogenesis, but recent findings also point to an intriguing role of the Cav2.3 E/R-type Ca2+ channel in ictogenesis and seizure propagation. Based on the observation that Cav2.3 is thought to induce plateau potentials in CA1 pyramidal cells, which can trigger epileptiform activity, our recent investigation revealed reduced PTZ-seizure susceptibility and altered seizure architecture in Cav2.3−/− mice compared with controls. In the present study we tested hippocampal seizure susceptibility in Cav2.3-deficient mice using surface and deep intrahippocampal telemetric EEG recordings as well as phenotypic seizure video analysis. Administration of kainic acid (30 mg/kg ip) revealed clear alteration in behavioral seizure architecture and dramatic resistance to limbic seizures in Cav2.3−/− mice compared with controls, whereas no difference in hippocampal EEG seizure activity between both genotypes could be detected at this suprathreshold dosage. The same tendency was observed for NMDA seizure susceptibility (150 mg/kg ip) approaching the level of significance. In addition, histochemical analysis within the hippocampus revealed that excitotoxic effects after kainic acid administration are absent in Cav2.3−/− mice, whereas Cav2.3+/+ animals exhibited clear and typical signs of excitotoxic cell death. These findings clearly indicate that the Cav2.3 voltage-gated calcium channel plays a crucial role in both hippocampal ictogenesis and seizure generalization and is of central importance in neuronal degeneration after excitotoxic events.

LAS24/KOG1, a component of the TOR complex 1 (TORC1), is needed for resistance to local anesthetic tetracaine and normal distribution of actin cytoskeleton in yeast

It is known that some local anesthetics inhibit the growth of budding yeast cells. To investigate the pathway of local anesthetics' action, we isolated and characterized mutants that were hyper-sensitive to tetracaine, and at the same time, temperature-sensitive for growth. They were collectively called las (local anesthetic sensitive) mutants. One of the LAS genes, LAS24, was found to be identical to KOG1, which had been independently discovered as a member of the TOR complex 1 (TORC1). Las24p/Kog1p is a widely conserved TOR binding protein containing the NRC domain, HEAT repeats and WD-40 repeats, but its function remains unknown. Like the tor mutants, the las24 mutants were found to have a defect in cell wall integrity and to show sensitivity to rapamycin. Furthermore, Las24p is required not only in TORC1-mediated (rapamycin-sensitive) pathways such as translation initiation control and phosphorylation of Npr1p and Gln3p, but also for the normal distribution of the actin cytoskeleton, which has been regarded as a TORC2-mediated event. Intriguingly, the temperature-sensitivity of the las24 mutant was suppressed by either activation of Tap42/PPase or by down-regulation of the RAS/cAMP pathway. Suppressors of the temperature-sensitivity of the las24-1 mutant were found not to be effective for suppression of the tetracaine-sensitivity of the same mutant. These observations along with the facts that tetracaine and high temperature differentially affected the las24-1 mutant suggest that Las24p/Kog1p is not a target of tetracaine and that the tetracaine-sensitive step may be one of downstream branches of the TORC1 pathway. Consistent with the broad cellular functions exerted by the TOR pathway, we found that Las24p was associated with membranes and was localized at vacuoles, the plasma membrane and small vesicles.