Antinociceptive effects of systemic lidocaine: involvement of the spinal glycinergic system.

Beside their action on voltage-gated Na(+) channels, local anesthetics are known to exert a variety of effects via alternative mechanisms. The antinociceptive effect of lidocaine is well documented, yet the exact mechanism is not fully understood. Whether glycinergic mechanisms, which play a pivotal role in pain modulation, are involved in lidocaine-induced antinociception is hitherto unclear.

Racemic intrathecal mirtazapine but not its enantiomers acts anti-neuropathic after chronic constriction injury in rats.

The unique noradrenergic and specific serotonergic antidepressant mirtazapine acts antinociceptive. It is optically active and currently marketed as racemate. In an animal model of acute pain it has been shown that the enantiomers exhibit differential effects: the R(-)-enantiomer showed anti-, the S(+)-enantiomer pronociceptive properties while the racemate acted antinociceptive at low doses and profoundly pronociceptive after high-dose application.

Differential effects of spinally applied glycine transporter inhibitors on nociception in a rat model of neuropathic pain.

Changes in glycinergic neurotransmission in the spinal cord dorsal horn are critically involved in the development of pathological pain. Since the concentration of glycine in the synaptic cleft is controlled by specialized proteins, the glycine transporters GlyT1 and GlyT2, manipulation of this system might have significant effects on nociception. In the present study, we investigated the effects of the spinally applied glycine transporter inhibitors ALX 5407 (GlyT1) and ALX 1393 (GlyT2) on nociceptive behavior in the chronic constriction injury model of neuropathic pain in male Wistar rats.

Stimulating catheter as a tool to evaluate peripheral nerve function during hip rotationplasty.

Objective: Stimulating catheters have been introduced into clinical practice to confirm perineural localization of the catheters. The muscular twitch induced over the catheter may be used to evaluate nerve function intraoperatively. Therefore, the function of the sciatic nerve was evaluated during major cancer surgery of the femur.

Skin temperature after interscalene brachial plexus blockade.

Background And Objectives: In neuraxial anesthesia, increase of skin temperature is an early sign of successful block. Yet, during peripheral nerve block of the lower extremity, increase in skin temperature is a highly sensitive, but late sign of a successful block. We hypothesized that after interscalene brachial plexus block, a rise in skin temperature follows impairment of sensation during successful nerve block and occurs only distally, as observed in the lower extremity.

Lidocaine induces apoptosis via the mitochondrial pathway independently of death receptor signaling.

Background: Local anesthetics, especially lidocaine, can lead to persistent cauda equina syndrome after spinal anesthesia. Recently, lidocaine has been reported to trigger apoptosis, although the underlying mechanisms remain unknown. To elucidate the pathway of lidocaine-induced apoptosis, the authors used genetically modified cells with overexpression or deficiencies of key regulators of apoptosis.

Regeneration of baroafferents after implantation into different vessels.

Regeneration of peripheral nerves involves an essential contribution by surrounding tissues. This study focuses on the role of the target tissue on the regeneration of afferent peripheral nerves. We hypothesized that nerves implanted into the appropriate target tissue regain their function, whereas they degenerate when implanted into a different tissue.

A single intravenous dose of prednisolone induces phosphatidylserine externalization, loss of surface marker expression and a 24-h net increase in human peripheral blood lymphocytes ex vivo.

To understand how corticosteroids act; a characterization of their effects on lymphocytes is necessary. The effect of in vivo corticosteroids on lymphocyte subpopulations, their surface molecules and externalization of phosphatidylserine (apoptosis) is examined. In a crossover study, a single, intravenous dose of 2 mg/kg prednisolone or saline was given to six male adult human volunteers.

Does interscalene catheter placement with stimulating catheters improve postoperative pain or functional outcome after shoulder surgery? A prospective, randomized and double-blinded trial.

Background: In this prospective, randomized, double-blind trial we investigated the use of stimulating catheters in patients during and after shoulder surgery; functional improvement being the primary outcome measurement.

Methods: After eliciting an adequate muscular twitch at < or =0.5 mA nerve stimulation output, the perineural catheter was advanced either blindly (conventional catheter = CC group, n = 20) or guided by stimulation via the catheter (stimulating catheter = SC group, n = 20).

Uniform distribution of skin-temperature increase after different regional-anesthesia techniques of the lower extremity.

Background And Objectives: Skin-temperature increase is a reliable but late indicator of success during regional-anesthesia techniques. The goal of this study is to determine the distribution of skin-temperature changes during different regional techniques. Does skin temperature increase in the whole area innervated by the blocked neural structures or only in certain regions within this area with the capability to react preferentially to sympathetic block (i.

Increase in skin temperature after spinal anesthesia in infants.

Background And Objectives: The relatively stable hemodynamics during spinal anesthesia in infants have been attributed to a less active sympathetic nervous system in comparison with adults. Thus, the authors evaluated sympathetic block primarily by measurement of skin temperature and secondarily by determination of noninvasive blood pressure as an indirect sign of sympatholysis.

Methods: In 15 infants (postconceptual age: 45.

Assessment of somatosensory evoked potentials during resuscitation of a 15-year-old boy with Duchenne muscular dystrophy.

Patients with Duchenne muscular dystrophy (DMD) are likely to suffer from cardiac insufficiency. Subclinical cardiac insufficiency may decompensate intraoperatively. During spinal surgery, recording of somatosensory evoked potentials (SSEP) is the standard method of spinal cord monitoring.

Skin temperature during regional anesthesia of the lower extremity.

Increase in skin temperature (Ts) occurs early during neuraxial blocks. However, the reliability of Ts to predict successful peripheral block is unknown. Therefore, we investigated whether an increase in Ts more than 1 degrees C precedes or follows an impairment of sensation after combined femoral and sciatic nerve block as well as after epidural anesthesia.

Mirtazapine and its enantiomers differentially modulate acute thermal nociception in rats.

The antidepressant mirtazapine is an optically active drug and currently marketed as a racemic compound consisting of its S(+) and R(-)-enantiomers in a 50:50 mixture. As stereochemistry of antidepressants has become increasingly important to consider for the relevance of their analgesic properties, we investigated the effect of (+/-)-mirtazapine and its enantiomers in an animal model of acute thermal nociception. Wistar rats were injected intrathecal with either (+/-)-mirtazapine, R(-)-mirtazapine, S(+)-mirtazapine from 1 to 0.

PONV: a problem of inhalational anaesthesia?

Even nowadays every third or fourth patient suffers from postoperative nausea and vomiting (PONV) after general anaesthesia with volatile anaesthetics. There is now strong evidence that volatile anaesthetics are emetogenic and that there are no meaningful differences between halothane, enflurane, isoflurane, sevoflurane, and desflurane in this respect. However, when propofol is substituted for volatile anaesthetics the risk for PONV is reduced by only about one fifth, indicating that there are other even more important causes for PONV following general anaesthesia.

The spinal antinociceptive effect of nocistatin in neuropathic rats is blocked by D-serine.

Background: The neuropeptide nocistatin (NST) has been implicated in the modulation of nociceptive responses in the spinal cord. Depending on the dose, both pronociceptive and antinociceptive effects have repeatedly been reported. The pronociceptive effect is most likely attributable to inhibition of synaptic glycine and gamma-aminobutyric acid release and a subsequent reduction in the activation of inhibitory glycine and gamma-aminobutyric acid receptors, but the mechanisms of its antinociceptive action have hitherto remained elusive.

Muscle weakness and paresthesia associated with epidural analgesia in a patient with an intrathecal neurofibrolipoma as part of a tethered cord syndrome.

We report a case of a 75-yr-old female patient in whom motor deficits and paresthesias occurred after lumbar epidural analgesia. These symptoms were eventually found to be due to a tethered cord syndrome. An epidural catheter was inserted for analgesia after colon surgery.

A preoperative retrobulbar block in patients undergoing scleral buckling reduces pain, endogenous stress response, and improves vigilance.

Background And Objectives: This study aims to test postoperative analgesia by using retrobulbar block in patients with retinal detachment surgery.

Methods: Twenty-nine patients scheduled for scleral buckling were included in this double-blind, randomized, prospective study. After induction of general anesthesia and opening of the conjunctiva, patients received either 4 mL bupivacaine 0.

Facilitation of spinal NMDA receptor currents by spillover of synaptically released glycine.

In the mammalian CNS, N-methyl-D-aspartate (NMDA) receptors serve prominent roles in many physiological and pathophysiological processes including pain transmission. For full activation, NMDA receptors require the binding of glycine. It is not known whether the brain uses changes in extracellular glycine to modulate synaptic NMDA responses.

Preemptive analgesia: no relevant advantage of preoperative compared with postoperative intravenous administration of morphine, ketamine, and clonidine in patients undergoing transperitoneal tumor nephrectomy.

Background And Objectives: Preemptive analgesia often failed in the clinical arena because application of a single intravenously applied drug may not prevent nociceptive input and spinal pain processing sufficiently. We therefore used an intravenous (IV), multireceptor approach and tested the preemptive analgesic effect of the antinociceptive drugs morphine, ketamine, and clonidine given before or immediately after surgery.

Methods: A double-blind, randomized, prospective study was performed in 30 patients undergoing transperitoneal tumor nephrectomy (via median laparotomy).

Effect of pre- or post-traumatically applied i.v. lidocaine on primary and secondary hyperalgesia after experimental heat trauma in humans.

Hyperalgesia on intradermal capsaicin application can be attenuated by systemic application of local anesthetics. We tested whether low doses of local anesthetics applied pre- or post-traumatically can reduce heat trauma-induced primary and secondary hyperalgesia in humans. Six healthy volunteers consented to the randomized, double-blind, and cross-over designed study.