Neuroscience letters
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Neuroscience letters · Mar 1995
Contribution of the sciatic and saphenous nerve to the ventrobasal thalamic neuronal responses to pinch in rats with a chronic sciatic nerve constriction: a study using anesthetic blocks and nerve section.
To extend the study on the respective contribution of the sciatic and saphenous nerve in abnormal nociceptive responses observed in rats with a loose constriction of one sciatic nerve, neuronal responses to pinch applied to the territory of the injured nerve, recorded in the ventrobasal complex of the thalamus have been studied. Eleven neurones recorded in 11 rats with a nerve constriction since 15-19 days and clear abnormal pain-related behaviour to mechanical stimulus, were tested before and during an anesthetic block of the saphenous and/or of the sciatic nerve, and/or after the saphenous nerve section. Only the sciatic nerve block depressed significantly the pinch responses.
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Neuroscience letters · Mar 1995
Galanin is contained in GABAergic neurons in the rat spinal dorsal horn.
In order to determine which types of neuron in laminae I-III of the rat spinal dorsal horn contain the peptide galanin, pre-embedding immunocytochemistry with antiserum to galanin was combined with post-embedding detection of GABA- and glycine-like immunoreactivities. Sixty-eight galanin immunoreactive neurons in laminae I-III selected from four rats were examined, and in each case semi-thin sections through the cell body were tested with a monoclonal antibody to GABA and an antiserum to glycine. All of the 68 galanin-immunoreactive neurons tested were GABA-immunoreactive, while only one of them (in lamina III) was glycine-immunoreactive. This suggests that galanin is contained in inhibitory interneurons, and that (like enkephalin, neuropeptide Y and thyrotropin-releasing hormone) it is mainly restricted to GABAergic neurons which do not use glycine as a co-transmitter.
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Neuroscience letters · Feb 1995
Quantitative evaluation of calcitonin gene-related peptide and substance P levels in rat spinal cord following peripheral nerve injury.
Levels of calcitonin gene-related peptide immunoreactivity (CGRP-ir) and substance P immunoreactivity (SP-ir) in the lumbar dorsal spinal cord of rats with either sciatic nerve transection or chronic constriction injury (CCI) were measured using radioimmunoassay. Significant decreases in CGRP-ir and SP-ir occurred in the ipsilateral spinal cord at 10 and 31 days after nerve transection. ⋯ Transection of the sciatic nerve produced greater decreases in peptide levels than did the CCI. Changes in spinal levels of these peptides may be involved in the appearance of neuropathic signs associated with nerve injury.
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Neuroscience letters · Feb 1995
Etomidate potentiation of GABAA receptor gated current depends on the subunit composition.
The role of the gamma 2 subunit in etomidate potentiation of GABAA receptor-gated chloride current was studied by whole cell patch clamp experiments on H293 cells expressing GABAA receptors. The GABAA receptor subunits alpha 1 beta 1 with or without the gamma 2 subunit expressed well, with an overall peak current of 157 +/- 42 pA/pF. ⋯ This gamma 2 subunit-dependent prolongation of the current time course was not blocked by the benzodiazepine receptor antagonist flumazenil. These results show that etomidate, an imidazole general anesthetic, interacts with the GABAA receptor in a gamma 2 subunit-dependent manner.
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Neuroscience letters · Sep 1994
Substance P binding sites on intestinal lymphoid aggregates and blood vessels in inflammatory bowel disease correspond to authentic NK-1 receptors.
Previous reports have described the ectopic expression of substance P binding sites on lymphoid aggregates and small blood vessels in inflammatory bowel disease. In this report, three non-peptide NK-1 receptor antagonists, CP-96,345, RP-67,580, and L-703,606 abolished saturable 125I-Bolton-Hunter substance P binding to the ectopically expressed receptors in frozen sections of surgically resected bowel from five patients with either Crohn's disease or ulcerative colitis. The rank order of affinity was approximately substance P approximately CP-96,345 approximately L-703,606 > RP-67,580. These results suggest that: (i) the ectopically expressed substance P binding sites in inflammatory bowel disease are authentic NK-1 receptors, (ii) all ectopically expressed receptors on small blood vessels, and lymphoid aggregates as well as normally expressed receptors on the bowel circular muscle have similar receptor affinities and specificities for substance P and the non-peptide antagonists, and (iii) non-peptide antagonists may be therapeutically beneficial in inflammatory bowel disease by inhibiting the pro-inflammatory effects of substance P acting via the NK-1 receptor.