Stress induced analgesia (SIA) is well known, but the reverse phenomenon, hyperalgesia is poorly documented. This study investigated the role of the histaminergic system in restraint stress hyperalgesia in rats, using thermal stimulation method (hot plate and tail flick tests). Paw licking and tail withdrawal latencies were taken before and after restraint for about one hour. Significant decrea...

The ability of allergens to induce hyperalgesia in immunoglobulin E (IgE)-sensitized rats was investigated. The left hind paws of Wistar rats were sensitized with intraplantar injections of IgE anti-dinitrophenylated bovine serum albumin monoclonal antibody, and challenged with dinitrophenylated bovine serum albumin 24 h later. Allergen challenge yielded rapid thermal hyperalgesia and oedema fo...

The enaminone methyl 4-(4'-bromophenyl)aminocyclohex-3-en-6-methyl-2-oxo-1-oate (E139) has anticonvulsant activities. It has been reported to have a better safety profile than some anticonvulsant drugs. Since some anticonvulsant drugs are used in the management of neuropathic pain, we evaluated the effects of E139 in rodent models of acute pain and paclitaxel-induced neuropathic pain. The react...

Noradrenaline (NA), a key neurotransmitter of the endogenous pain inhibitory system, acutely inhibits nociceptive transmission (including that mediated by substance P), potentiates opioid analgesia, and underlies part of the antinociceptive effects of the widely prescribed tricyclic antidepressants. Lesions of noradrenergic neurons, however, result in either normal or reduced pain behavior and ...

Problem statement: The objective of this study was to evaluate pain sensitisation in rats following the induction of an intracerebral hemorrhage by injecting a collagenase solution in the caudoputamen nucleus of the right basal ganglia and to evaluate gabapentin as an analgesic for central pain. Approach: Thirty male Sprague-Dawley rats weighing between 175-300 g were used. In a first experimen...

BACKGROUND AND THE PURPOSE OF THE STUDY Pentoxifylline (PTX) is a non-specific cytokite pain in several animal models and humans. However, long-term therapeutic effects of PTX on neuropathic pain in a rat model of chronic constriction injury (CCI) are not completely clear. This study was conducted to examine the effect of long-term administration of PTX on neuropathic pain in rats. METHODS Ne...

Background: The endocannabinoid system interacts with the vanilloid and opioid systems. The current study aims to investigate the effects of the extract obtained from the heated Cannabis Sativa female flower base either with capsaicin at the spinal cord level or naloxone at the systemic level on the intensity of chemical and thermal pain sensation. Methods: This experimental study was performe...

Primarily opioidergic and adenosine mechanisms are considered to be involved in the antinociceptive effects of antidepressants. This study was designed to determine the efficacy of acute venlafaxine administration in alleviating symptoms of neuropathic pain and the role of endogenous adenosine and opioid systems in this effect of venlafaxine. We have evaluated the effect of caffeine, a non-sele...

Melatonin (MT) is a neurohormone synthesized and secreted by the pineal gland. MT plays an important role in the regulation of physiological and neuroendocrine functions. The purpose of this study was to assess the overall effect of melatonin on neuropathic pain, the type of melatonin receptor involved, and potential role of the opioid system and GABA(A) receptors. The experiments were conducte...

BACKGROUND Clonidine can effectively reduce pain and/or hypersensitivity. However, the antihypersensitivity effects of clonidine topically applied in cream (CC) have not been investigated. The authors evaluated effects of topical application of CC on pain behaviors and spinal Fos-like immunoreactivity in rats with hypersensitivity. METHODS Clonidine (30, 100, and 300 microg/g) was prepared in...