Neuroscience letters
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Neuroscience letters · Apr 2006
Acetyl-L-carnitine prevents and reduces paclitaxel-induced painful peripheral neuropathy.
This study examines the potential efficacy of acetyl-L-carnitine (ALC) to prevent and treat paclitaxel-induced pain. Rats received four intraperitoneal (i.p.) injections of 2 mg/kg paclitaxel on alternate days which, following a short delay induced marked mechanical hypersensitivity. Daily administration of ALC (50 mg/kg and 100 mg/kg; p.o.; concurrently with paclitaxel and for 14 days afterwards) prevented the development of paclitaxel-induced pain. ⋯ In a separate experiment, daily administration of ALC (100 mg/kg; p.o.; for 10 days) to rats with established paclitaxel-induced pain produced an analgesic effect. This effect dissipated shortly after ALC treatment was withdrawn. We conclude that ALC may be useful in the prevention and treatment of chemotherapy-induced painful peripheral neuropathy.
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Neuroscience letters · Apr 2006
Role of the basolateral nucleus of the amygdala in endocannabinoid-mediated stress-induced analgesia.
Recent work in our laboratories has demonstrated that an opioid-independent form of stress-induced analgesia (SIA) is mediated by endogenous ligands for cannabinoid receptors-anandamide and 2-arachidonoylglycerol (2-AG) [A. G. Hohmann, R. ⋯ To examine the contribution of endocannabinoids in the BLA to SIA, we used selective pharmacological inhibitors of the anandamide-degrading enzyme fatty-acid amide hydrolase (FAAH) and the 2-arachidonoylglycerol-degrading enzyme monoacylglycerol lipase (MGL). The FAAH inhibitor URB597 and MGL inhibitor URB602, at doses that enhanced SIA following microinjection in the midbrain periaqueductal gray, did not alter SIA relative to control conditions. Our findings suggest that CB1 receptors in the BLA but not the CeA contribute to SIA, but pharmacological inhibition of endocannabinoid degradation at these sites does not affect the expression of stress antinociception.
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Neuroscience letters · Apr 2006
NSAID zaltoprofen possesses novel anti-nociceptive mechanism through blockage of B2-type bradykinin receptor in nerve endings.
Zaltoprofen, a propionic acid derivative of non-steroidal anti-inflammatory drugs (NSAIDs), was shown to have more powerful inhibitory effects to bradykinin (BK)-nociception than other NSAIDs. However, the molecular mechanisms underlying this potent analgesia are not yet fully understood. Here we attempted to clarify the molecular mechanism underlying zaltoprofen-induced analgesia on BK-induced nociception by a novel algogenic-induced paw flexion (APF) test in mice. ⋯ Zaltoprofen also inhibited the nociception induced by [Tyr8]-BK, a specific agonist of B2-type BK receptor, but did not affect the nociception by [Lys-des-Arg9]-BK, a specific agonist of B1-type BK receptor. However, zaltoprofen did not affect the substance P-induced nociception, which is mediated by common post-receptor signaling through nociceptive fibers with BK-ones. All these results suggest that NSAID zaltoprofen possesses novel anti-nociceptive mechanism, which inhibits B2-type BK receptor function in nerve endings.
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Neuroscience letters · Apr 2006
Comparative StudyOptical coherence tomography reveals in vivo cortical plasticity of adult mice in response to peripheral neuropathic pain.
We examined neural plasticity in mice in vivo using optical coherence tomography (OCT) of primary somatosensory (S1) and motor (M1) cortices of mice under the influence of sciatic nerve chronic constriction injury (CCI), a model of neuropathic pain widely utilized in rats. The OCT system used in this study provided cross-sectional images of the cortical tissue of mice up to a depth of about 1mm with longitudinal resolution up to 11 microm. This is the first study to evaluate neural plasticity in vivo using OCT. ⋯ Synapses and mitochondria are believed to have high light scattering coefficients, since they contain remarkably high concentrations of proteins and complicated membrane structure. Number densities of mitochondria and synapses are known to increase in parallel with increases in neural activity. Our findings thus suggest that neuropathic pain gives rise to neural plasticity within the hind paw area of S1 and M1 contralateral to the ligated sciatic nerve.