Effect of gabapentin and lamotrigine on mechanical allodynia-like behaviour in a rat model of trigeminal neuropathic pain.

Injury to the trigeminal nervous system may induce severe pain states. This study examined the antinociceptive effect of the novel anticonvulsants, gabapentin and lamotrigine, in a rat model of trigeminal neuropathic pain produced by chronic constriction of one infraorbital nerve. Responsiveness to von Frey filament stimulation of the vibrissal pad was evaluated 2 weeks post-operation.

Lack of cross-tolerance between the antinociceptive effects of systemic morphine and asimadoline, a peripherally-selective kappa-opioid agonist, in CCI-neuropathic rats.

The development of tolerance following repeated doses of morphine hinders the treatment of clinical pain. We have previously shown that morphine tolerance develops in neuropathic rats without cross-tolerance to a systemic kappa-opioid agonist; in the current work, using paw-pressure vocalization thresholds, we studied the antinociceptive effect of the peripherally-selective kappa (kappa)-opioid agonist, asimadoline, in both morphine-tolerant and opioid-naïve rats 2 weeks after sciatic nerve injury. In naïve rats, intraplantar (i.

Combined systemic administration of the glycine/NMDA receptor antagonist, (+)-HA966 and morphine attenuates pain-related behaviour in a rat model of trigeminal neuropathic pain.

Chronic constriction injury to the infraorbital nerve (CCI-ION) by loose ligatures may represent a useful model for some trigeminal neuropathic pain disorders. Activation of the N-methyl-D-aspartate (NMDA) receptor is involved in the induction and maintenance of neuropathic pain and may contribute to the poor opioid sensitivity of this syndrome. We evaluated the effect of combined systemic administration of the functional antagonist at the glycine site of the N-methyl-D-aspartate (NMDA) receptor complex, (+)-(1-Hydroxy-3-aminopyrrolodine-2-one) ((+)-HA966) with morphine on mechanical allodynia-like behaviour in CCI-ION rats.

Time-course of nociceptive disorders induced by chronic loose ligatures of the rat sciatic nerve and changes of the acetylcholinesterase transport along the ligated nerve.

Changes in the axonal transport of acetylcholinesterase (AChE) were studied in the painful mononeuropathy induced by setting 4 loose ligatures around the right sciatic nerve of the rat. Since changes in the axonal transport of AChE can be used to assess axonal degeneration/regeneration, we used this marker to investigate whether the time course of pain-related behavioral disorders observed following chronic constriction injury (CCI) to the sciatic nerve are related to the time course of the regeneration of the injured axons. In addition, a comparison was made between changes in AChE observed in this model of nerve injury and those observed after sciatic nerve crush.

Nociceptive responses in medial thalamus of the normal and arthritic rat.

Recordings were obtained from 773 neurons located in the medial thalamus of rats. 23 of the 46 rats studied had been rendered arthritic by prior inoculation with Freund's adjuvant. 262 of the neurons could be activated by peripheral stimulation.

The organization of spinal pathways to ventrobasal thalamus in an experimental model of pain (the arthritic rat). An electrophysiological study.

The spinal ascending pathways responsible for neuronal ventrobasal (VB) thalamic responses elicited by joint stimulation of the posterior paw were determined in arthritic rats used as a model of experimental pain. Responses of a same neurone to mechanical (movement--pressure--brushing) or thermal stimulation (50 degrees C) were analysed before and after discrete lesions in the white matter of the spinal cord. For 6 neurones responding exclusively to brushing applied on a small receptive field (RF) strictly contralateral to the recording site, responses were not altered as long as the contralateral dorsal column was intact.

Functional changes in ventrobasal thalamic neurones responsive to noxious and non-noxious cutaneous stimuli after chloralose treatment: new evidence for the presence of pre-existing "silent connections" in the adult nervous system?

Twenty-five neurones of the thalamic VB complex of the rat, first characterized under moderate volatile anaesthesia (1/3 oxygen - 2/3 nitrous oxide, 0.5% halothane) were subsequently studied under deep chloralose anaesthesia. As described in a previous study, neurones were classified during the control period as "noxious" (N) "non-noxious" (Nn), or "convergent" (NnN) according to their responsiveness to cutaneous mechanical stimulations.