Experimental neurology
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Experimental neurology · Jun 2011
Protection against oxaliplatin-induced mechanical hyperalgesia and intraepidermal nerve fiber loss by minocycline.
Treatment with the chemotherapeutic agent oxaliplatin produces a robust painful neuropathy similar to various other neuropathic conditions which result in loss of nerve fibers innervating the skin. This loss of intraepidermal nerve fibers (IENFs) appears to play an important role in neuropathy, but has yet to be investigated in oxaliplatin-induced neuropathic pain. For this study, mechanical hyperalgesia and IENF density were measured in rats receiving oxaliplatin, given at a dosage of 2 mg/kg every other day for four injections. ⋯ Immunohistochemistry using the pan-neuronal marker PGP9.5 was used to investigate IENF densities in hind paw skin on Day 15 and Day 30. The results show that a robust mechanical sensitivity developed in oxaliplatin treated animals, as did a pronounced decrease in epidermal nerve fibers, and these outcomes were effectively prevented by minocycline treatment. This is the first study to show changes in IENF density in oxaliplatin treated animals, and confirm not only a relationship between IENF loss and hypersensitivity but also prevention of both with minocycline treatment.
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Experimental neurology · May 2011
Comparative StudyOlfactory ensheathing cells enhance Schwann cell-mediated anatomical and functional repair after sciatic nerve injury in adult rats.
Sciatic nerve injury results in axon damage, muscle degeneration, and loss of function. We compared the potential of Schwann cell (SC), olfactory ensheathing cell (OEC), or mixed SC/OEC transplants for anatomical and functional restoration after adult rat sciatic nerve transection. The cells were seeded into a 20mm long macroporous poly(dl-lactide-co-glycolide) acid conduit and grafted between the sciatic nerve stumps. ⋯ Our results revealed that OEC synergistically improve SC mediated sciatic nerve repair. The data emphasized the promise of SC/OEC transplants as artificial nerves for peripheral nerve repair. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair.
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Experimental neurology · Apr 2011
Lesion of cholinergic neurons in nucleus basalis enhances response to general anesthetics.
Acetylcholine in the brain has been associated with consciousness and general anesthesia effects. We tested the hypothesis that the integrity of the nucleus basalis magnocellularis (NBM) affects the response to general anesthetics. Cholinergic neurons in NBM were selectively lesioned by bilateral infusion of 192IgG-saporin in adult, male Long-Evans rats, and control rats were infused with saline. ⋯ However, the behavioral excitation, as indicated by horizontal movements, induced by halothane was reduced in lesioned as compared to control rats. Reversible inactivation of NBM with GABA(A) receptor agonist muscimol increased slow waves in the neocortex during awake immobility, and prolonged the duration of LORR and loss of tail-pinch response after propofol, pentobarbital and halothane. In summary, lesion of NBM cholinergic neurons or inactivation of the NBM prolonged the LORR response to general anesthetic drugs.
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Experimental neurology · Apr 2011
Comparative StudySex-related differences in descending norepinephrine and serotonin controls of spinal withdrawal reflex during intramuscular saline induced muscle nociception in rats.
Sex-associated differences in the perception and modulation of pain have widely been reported in humans as well as animals. The aim of the present study performed in conscious rats of both sexes was to systematically investigate the role of sex in endogenous descending controls of nociceptive paw withdrawal reflex during experimental muscle pain elicited by intramuscular (i.m.) injection with different doses (0.1-0.4 ml of 0.9-5.8%) of saline. Ipsilateral i.m. injection of 0.2-0.4 ml, but not 0.1 ml, isotonic (0.9%, IT) saline elicited long lasting (about 7d), secondary and contralateral mechanical hyperalgesia in female rats, whereas male rats exhibited a bilateral, short-term (less than 1d) mechanical hyperalgesia only during the exposure to 0.4 ml IT saline injection (P < 0.05). ⋯ In conclusion, sex-related differences are important in descending modulations of pain and anesthesia. Less noxious stimuli could activate descending inhibition in males but not females, whereas less noxious afferents may elicit descending facilitation in female, but not male rats. Central noradrenergic and serotonergic pathways are differently involved in the action of descending modulations of nociception in rats of both sexes.