Progress in neuro-psychopharmacology & biological psychiatry
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Prog. Neuropsychopharmacol. Biol. Psychiatry · Aug 2012
A novel trigeminal neuropathic pain model: compression of the trigeminal nerve root produces prolonged nociception in rats.
We demonstrate the establishment of a novel animal model for trigeminal neuropathic pain following compression of the trigeminal nerve root, which produces prolonged nociceptive behavior and demyelination of the trigeminal nerve root. Under anesthesia, male Sprague-Dawley rats (200-230 g) were mounted onto a stereotaxic frame and injections of a 4% agar solution (10 μl) were given to achieve compression of the trigeminal nerve root. A sham operation was performed using identical procedures but without agar injections. ⋯ In the medullary dorsal horn, phospho-p38 (p-p38) mitogen-activated protein kinase (MAPK) was found to be exclusively expressed in the microglia on POD 14. Furthermore, intraperitoneal administration of carbamazepine (50mg/kg) significantly blocked mechanical allodynia and reduced p38 MAPK activation induced by the compression of the trigeminal nerve root. Our findings suggest that prolonged nociceptive behavior following compression of the trigeminal nerve root may mimic trigeminal neuralgia in this animal model and that the activation of p38 MAPK in the microglia contributes to pain hypersensitivity in rats that have undergone compression of the trigeminal nerve root.
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Prog. Neuropsychopharmacol. Biol. Psychiatry · Aug 2012
Tobacco smoking produces greater striatal dopamine release in G-allele carriers with mu opioid receptor A118G polymorphism.
To determine if carriers of the allelic expression of the G variant of the human mu opioid receptor (OPRM1) A118G polymorphism have greater increases in striatal dopamine (DA) release after tobacco smoking. ⋯ This preliminary study indicates a difference in both brain striatal DA release and plasma cortisol in A118G polymorphic male tobacco smokers.
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Prog. Neuropsychopharmacol. Biol. Psychiatry · Aug 2012
The anxiolytic-like effect of an essential oil derived from Spiranthera odoratissima A. St. Hil. leaves and its major component, β-caryophyllene, in male mice.
Spiranthera odoratissima A. St. Hil. (manacá) is used in folk medicine to treat renal and hepatic diseases, stomachache, headaches and rheumatism. ⋯ The anxiolytic-like effects of β-caryophyllene were not blocked by either NAN-190 or flumazenil (P>0.05). In conclusion, these results suggest that the essential oil derived from S. odoratissima produces an anxiolytic-like effect without altering motor performance and that this effect is mediated by 5-HT(1A) but not via benzodiazepine receptors. In addition, the major component, β-caryophyllene, also has an anxiolytic-like effect that may contribute to the effects of EO, but this effect does not seem to be mediated via 5-HT(1A) or benzodiazepine receptors.