We have previously shown that stimulation of peripheral opioid receptors by exogenous opiates counteracts the thermal hyperalgesia elicited by a tibial osteosarcoma due to intraosteal inoculation of NCTC 2472 cells to mice. Aiming to study whether pheripheral endogenous enkephalins could also counteract this painful symptom, we assayed in this model the effects of PL37, an orally active dual in...

Gabapentin and S-(+)-3-isobutylgaba are anticonvulsant agents that selectively interact with the alpha2delta subunit of voltage-dependent calcium channels. This report describes the activities of these two compounds in a rat model of postoperative pain. An incision of the plantaris muscle of a hind paw induced thermal hyperalgesia and tactile allodynia lasting at least 3 days. Postoperative tes...

BACKGROUND Plants rich in flavonoids, such as açaí (Euterpe oleraceae Mart.), can induce antinociception in experimental animals. Here, we tested an extract obtained from the stones of açaí fruits (açaí stone extract, ASE), a native plant from the Amazon region of Brazil, in models of acute/inflammatory and chronic pain. METHODS Antinociceptive effects of ASE were evaluated in the hot plate, ...

To clarify the role of peroxisome proliferator activated receptor gamma (PPARgamma) in neuropathic pain, we examined the effect of pioglitazone, a PPARgamma agonist, on tactile allodynia and thermal hyperalgesia in a neuropathic pain model. Mice were subjected to partial sciatic nerve ligation (PSL) and given pioglitazone (1 - 25 mg/kg, p.o.) once daily. PPARgamma was distributed in the neurons...

BACKGROUND Cannabinoid receptor agonists inhibit inflammatory hyperalgesia in animal models. Nonselective cannabinoid receptor agonists also produce central nervous system (CNS) side effects. Agonists selective for CB2 cannabinoid receptors, which are not found in the CNS, do not produce the CNS effects typical of nonselective cannabinoid receptor agonists but do inhibit acute nociception. The ...

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...

UNLABELLED The transient receptor potential cation channel subfamily M 8 (TRPM8) agonist L-menthol has been used traditionally for its topical counterirritant properties. Although the use of topical L-menthol for pain is casuistically established, evidence regarding its efficacy is negligible. This study aimed to characterize the effect of L-menthol as a counterirritant on cutaneous pain and hy...

Introduction: Peripheral and central nerve injuries cause chronic neuropathic pain in many injured people besides motor disability. Exercise, as a behavioral and non-pharmacological treatment, has beneficial effects on people’s general health both for healthy and sick people. Therefore, this study was conducted to examine the effects of exercise on neuropathic pain induced by chronic cons...

Hormone replacement remains one of the common therapies for menopause-related pain but is associated with risk of orofacial or back pain. Spinal endomorphin-2 (EM-2) is involved in varied pain and its release is steroid-dependent, but whether increasing spinal EM-2 can inhibit thermal hyperalgesia and inflammatory pain in ovariectomized (OVX) female rats, an animal model mimicking menopause, is...

Nootropic drug nefiracetam and related compounds are used in diseases with learning and memory deficits. Recent studies have implicated relationships between learning, memory, and chronic pain. Thus, in the present report, we have studied the effects of nootropic drug nefiracetam on the thermal and mechanical hyperalgesia induced by partial sciatic nerve ligation or streptozotocin treatment in ...