Spinal and cortical spreading depression enhance spinal cord activity.

Cortical spreading depression (CSD) has been suggested to underlie some neurological disorders such as migraine. Despite the intensity with which many investigators have studied SD in the brain, only a few studies have aimed to identify SD in the spinal cord. Here we described the main characteristic features of SD in the spinal cord induced by different methods including various spinal cord injury models and demonstrated that SD enhances the spinal cord activity following a transient suppressive period.

Spinal glutamate receptor antagonists differentiate primary and secondary mechanical hyperalgesia caused by incision.

Secondary mechanical hyperalgesia has been demonstrated in postoperative patients indicating that central sensitization occurs after surgery. However, the underlying mechanisms are unknown. Here, we studied the role of spinal N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)/kainate receptors for pain behaviors indicating secondary hyperalgesia caused by gastrocnemius incision in the rat.

Degeneration of myelinated efferent fibers induces spontaneous activity in uninjured C-fiber afferents.

We demonstrated recently that uninjured C-fiber nociceptors in the L4 spinal nerve develop spontaneous activity after transection of the L5 spinal nerve. We postulated that Wallerian degeneration leads to an alteration in the properties of the neighboring, uninjured afferents from adjacent spinal nerves. To explore the role of degeneration of myelinated versus unmyelinated fibers, we investigated the effects of an L5 ventral rhizotomy in rat.

Persistent secondary hyperalgesia after gastrocnemius incision in the rat.

Secondary hyperalgesia, an exaggerated response to stimuli applied to undamaged tissue surrounding an injury, is a common consequence of tissue injury and inflammation. It is well established that the etiology of secondary hyperalgesia is sensitization of central neurons but the exact mechanism and its role in certain clinical pain states is unclear. In the present experiments, we studied responses to punctate and non-punctate mechanical stimuli and to heat applied to the plantar aspect of the hindpaw remote to an incision in the gastrocnemius region of the rat hindlimb.

Effect of plantar local anesthetic injection on dorsal horn neuron activity and pain behaviors caused by incision.

Hypersensitivity after tissue injury is an expression of neuronal plasticity in the central nervous system. This has been explored most extensively using in vitro preparations and animal models of inflammatory pain and chemical irritation. For pain after surgery, a similar process has been proposed.

Role of the rostral medial medulla in the development of primary and secondary hyperalgesia after incision in the rat.

Background: Descending influences from the rostral medial medulla (RMM) contribute to secondary hyperalgesia in persistent inflammatory, neuropathic, and visceral pain models. The current study examined if descending inhibition or facilitation from the RMM modulates primary and secondary hyperalgesia after incision in the rat hind limb.

Methods: Bilateral RMM lesions were produced using the soma-selective neurotoxin ibotenic acid, and the effect of RMM lesion was examined on primary and secondary hyperalgesia 5 days after a plantar or gastrocnemius incision, respectively.

Characterization of Adelta- and C-fibers innervating the plantar rat hindpaw one day after an incision.

Primary hyperalgesia after tissue injury is suggested to result from sensitization of primary afferent fibers, but sensitization to mechanical stimuli has been difficult to demonstrate. In the companion study, sensitization of mechano-responsive Adelta- and C-fibers did not explain pain behaviors 45 min after an incision in the rat hindpaw. In the present study, we examined mechanical response properties of Adelta- and C-fibers innervating the glabrous skin of the plantar hindpaw in rats 1 day after an incision or sham procedure.

Effect of pretreatment with intrathecal excitatory amino acid receptor antagonists on the development of pain behavior caused by plantar incision.

Background: Drugs that block spinal excitatory amino acid receptor activation may prevent pain after surgery. The authors previously studied the effect of excitatory amino acid receptor antagonists after incision. In the present study, we examined the role of N-methyl-d-aspartate (NMDA), non-NMDA, and metabotropic glutamate receptors (mGluRs) on the development of pain behavior after plantar incision.

Lumbar catheterization of the subarachnoid space with a 32-gauge polyurethane catheter in the rat.

Chronic catheterization of the subarachnoid space of rats is an important tool for intrathecal drug delivery in pharmacologic investigations of pain. We describe a technique using direct lumbar insertion of a small 32-gauge polyurethane (PU) catheter without extensive surgery. Location of the catheter was confirmed with 2% lidocaine injection 1 day later, and methylene blue injection after 7-14 days.

Experimental arthritis in the rat does not alter the analgesic potency of intrathecal or intraarticular morphine.

Unlabelled: To explore further the role of inflammatory processing on peripheral opioid pharmacology, we examined whether the potency of intraarticular (i.a.) or intrathecal (i.

Epidural analgesia with local anesthetics after abdominal surgery: earlier motor recovery with 0.2% ropivacaine than 0.175% bupivacaine.

Unlabelled: The aim of this prospective, randomized, double-blinded study was to compare pain relief, side effects, and ability to ambulate during epidural anesthesia with ropivacaine 0.2% plus sufentanil versus bupivacaine 0.175% plus sufentanil after major gastrointestinal surgery.

A multimodal approach to control postoperative pathophysiology and rehabilitation in patients undergoing abdominothoracic esophagectomy.

Unlabelled: This two-armed study was designed to determine whether recovery after esophageal resection may be improved by introducing a new multimodal approach. For 8 mo after the new approach was introduced, all patients undergoing abdominothoracic esophageal resection were studied (Group 2; n = 42). For comparison, a retrospective analysis was also conducted using the data of all patients who had undergone this operation in the 8 mo before the introduction of the new regimen, when the traditional therapy was still in use (Group 1; n = 49).

[A modern concept of postoperative pain therapy].

Pain relief should be considered part of a multimodal postoperative approach. Combining patient-controlled pain therapy with other measures i.e.

[Quality control in multimodal postoperative therapy].

Effects of anaesthesia and analgesia on postoperative morbidity and mortality remain controversial. Numerous studies have demonstrated that epidural anaesthesia and pain relief by epidural analgesia reduces perioperative stress responses and thus may reduce postoperative morbidity and mortality. In patients undergoing vascular surgery, epidural anaesthesia diminished postoperative hypercoagulability.

[Patient-controlled postoperative epidural analgesia. Prospective study of 1799 patients].

Unlabelled: Side effects of postoperative epidural analgesia can be controlled by two strategies: Insertion of catheters into the center of the affected spinal segments and coadministration of local anesthetics and opioids. Both techniques will reduce single drug dosage. Additionally synergistic effects will result in excellent analgesia and the risk of side effects and complications will be minimized.