摘要:

CARRAGEENAN was used to study inflammation-induced changes in spinal nociception and its brain stem modulation in the pentobarbitone-anesthetized rat. Carrageenan was administered intraplantarly into one hindpaw 2 h before the start of electrophysiological single unit recordings of wide-dynamic range (WDR) neurons of the spinal dorsal horn. Carrageenan produced a significant leftward shift in the stimulus–response function for mechanical stimuli, whereas that for noxious heat stimuli was short of statistical significance. Conditioning electrical stimulation in the rostroventromedial medulla (RVM) significantly attenuated noxious heat-evoked, but not mechanically evoked, responses to spinal dorsal horn WDR neurons in the control (contralateral) side. However, in the carrageenan-treated side RVM stimulation had no significant effect on mechanically or noxious heat-evoked responses. Following direct spinal administration of neuropeptide FF (NPFF), noxious heat-evoked responses, but not mechanically evoked responses, were attenuated by RVM-stimulation also in the carrageenan-treated side. This selective NPFF-induced enhancement of brain stem–spinal inhibition was not reversed by naloxone. The results indicate that carrageenan-induced inflammation significantly changes the response properties of spinal nociceptive neurons and their brain stem-spinal modulation. During inflammation, NPFF in the spinal cord produces a submodality-selective potentiation of the antinociceptive effect induced by brain stem–spinal pathways, independent of naloxone-sensitive opioid receptors.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

TO clarify the differential effects on spinal circuitry caused by physicalvsfunctional disconnection from the periphery, we compared changes produced by 3-, 7-or 14-day unilateral sciatic axotomy or tetrodotoxin (TTX) nerve blockade on the abundance or activity of NADPH diaphorase (NDP), cytochrome oxidase (CO) and acid phosphatase (AP) in the spinal cord. Following axotomy, AP and NDP were decreased in the dorsal horn and increased in large cells in the dorsolateral motor nuclei while CO was decreased in ventral horn neuropil. TTX induced a decrease of CO in the ventral horn and NDP in the dorsal horn. This suggests that physicalvsfunctional disconnection causes modulation of distinct intra-cellular pathways in sensory afferents, dorsal horn neurons and motoneurons.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID