Neuroscience letters
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Neuroscience letters · Jun 2000
Intracerebroventricular infusion of nerve growth factor induces pain-like response in rats.
New strategies have recently been developed where infusion of neurotrophic factors into the brain can rescue different neuronal populations. However, negative side effects have been observed in clinical trials infusing nerve growth factor (NGF) into the lateral ventricle in man, namely pain. Little is known about pain behavior in animals after intracerebroventricular (i.c.v.) neurotrophic injections. ⋯ The enhanced responses to mechanical and heat, but not to cold, stimulation were significantly reduced by CP-99994, a selective antagonist to tachykinin NK-1 receptors. When NGF was infused into the brain parenchyma (striatum, cortex and septum) no allodynic nor hyperalgesic responses could be detected. These results indicate that in rats i.c.v. but not intraparenchymal infusion of NGF induce mechanical and cold allodynia as well as heat hyperalgesia, which is mediated, at least in part, by activation of NK-1 receptors.
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Neuroscience letters · Jun 2000
Comparative StudyCo-existence of calcium-binding proteins in neurons of the medullary dorsal horn of the rat.
Double immunofluorescence histochemistry for calcium-binding proteins was performed in the caudal subnucleus of the rat spinal trigeminal nucleus; for calbindin D28k (CB) and calretinin (CR), for CB and parvalbumin (PV), and for CB and CR. CB-immunoreactive (-ir) neurons were seen 1.7 times more frequently than CR-ir neurons and 5.5 times more frequently than PV-ir neurons. About 70-90% of these neurons were distributed in substantia gelatinosa. ⋯ Co-existence of CB and PV was indicated in 1.0% of CB-ir and 5.5% of PV-ir neurons. Co-existence of CR and PV was indicated in 1.4% of CR-ir and 5.1% of PV-ir neurons. In these doubly immunostained neurons, 59.5-69.5% were observed in substantia gelatinosa, 5.9-17.8% in the marginal zone, and 12.7-31.0% in the magnocellular part.