ISSN:0897-7151    

DOI:10.1089/neu.1991.8.1

年代:1991

数据来源: MAL

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.3

年代:1991

数据来源: MAL

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.9

年代:1991

数据来源: MAL

摘要:

ABSTRACTThe excessive generation of free radicals is thought to be one of the major mechanisms leading to tissue injury in various pathological conditions, including ischemia, inflammation, and trauma. Conversion of xanthine dehydrogenase (XDH) to xanthine oxidase (XO) contributes to the formation of superoxide, an oxygen radical. We measured XDH and XO activity using a newly developed fluorometric assay in an experimental spinal cord injury model in rats. XO activity increased by more than 100% 4 h after spinal cord trauma. Total (XDH + XO) activity also increased by 96% during the same period. Allopurinol, an inhibitor of XO (100 mg/kg/day × 2 days, i.p.), completely inhibited plasma and spinal cord XO activity but did not affect posttraumatic edema determined by water content or polymorphonuclear (PMN) cell infiltration reflected by myeloperoxidase (MPO) activity in traumatized spinal cord. These results indicate that XDH conversion to XO may not be the major mechanism of oxygen radical formation in the pathogenesis of vasogenic edema or inflammatory response in this experimental spinal cord injury model in rats

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.11

年代:1991

数据来源: MAL

摘要:

ABSTRACTPlatelet-activating factor (PAF) receptor antagonists reportedly improve early postischemic neurological recovery and cerebral blood flow in selected experimental models. Their effects on posttraumatic cerebral edema have, however, not been examined. In a rat model of right hemispheric percussive cerebral trauma, we examined the effects of two PAF receptor antagonists on posttraumatic edema formation. Two groups of rats received either BN 52021 (n= 14) or WEB 2086 (n= 11), 10 mg/kg i.v. at 15 min posttrauma. Two other groups treated with the BN 52021 (n= 17) and WEB 2086 (n= 10) vehicles served as controls. Hemispheric percent brain water was determined at 24 h. Edema occurred in all groups. Neither PAF receptor antagonist significantly reduced right hemispheric percent brain water (81.08 ± 0.25 and 81.04 ± 0.15 in Bn 52021 and WEB 2086-treated rats, respectively, versus 81.31 ± 0.23 and 81.14 ± 0.17% brain water in BN 52021 vehicle and WEB 2086 vehicle-treated rats). Mortality was not statistically different between groups. These data do not support a major role for PAF in the development of posttraumatic cerebral ed

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.19

年代:1991

数据来源: MAL

摘要:

ABSTRACTThe relative safety and efficacy of direct versus indirect methods of spinal cord stimulation for the production of descending motor-evoked responses was studied in pentobarbital-anesthetized rats (n= 39). Electrical stimuli were delivered for 1 h, either directly to the cord dorsum using silver ball electrodes or indirectly through jeweler's screws implanted in the intact laminae. Compound muscle action potentials (CMAPs) were recorded differentially in the quadriceps and evaluated for their morphology and reproducibility. The traumatic effects of stimulation were assessed using intraoperative somatosensory-evoked potentials, blinded neurological examinations for 2 weeks postoperatively, and histopathological and neurochemical analyses in postmortem spinal tissues. In separate experiments, the neural substrates of the muscle-evoked response to indirect cord stimulation were examined. Direct, epidural stimulation of the spinal cord at intensities sufficient to elicit reproducible CMAPs consistently resulted in mild behavioral deficits (13 of 18 animals) that were accompanied by postmortem changes in spinal histology and chemistry. Some of these behavioral deficits (5 of 13 animals) were resolved at 2 weeks. There was rarely an early sign of motor or sensory conduction derangement in these animals. In 2 animals with severe behavioral dysfunction, the somatosensory-evoked response was abolished immediately after spinal stimulation. However, CMAP responses were unaltered. Examination of the strength–duration relationship for the production of threshold responses to translaminar constant current stimulation, as well as experiments using selective transection of the dorsal columns, revealed the CMAP responses to be neurally mediated and conducted through the cord independent of the ascending sensory tracts that mediate the rat's somatosensory-evoked response. Data are discussed in terms of the potential experimental usefulness of CMAPs elicited by indirect dorsal spinal stimulatio

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.27

年代:1991

数据来源: MAL

摘要:

ABSTRACTThe effects of distraction injury to the spinal cord on serotonin (5HT) content and metabolism in a rat model of scoliosis were studied. Previous studies in this laboratory (Salzman et al., 1987a) have identified the 5HT response as a major component of the posttraumatic progression of spinal injury after impact trauma in the rabbit. The present study was designed to determine the universality of this response by examining a different model of injury in a different species. The results demonstrate that distraction trauma in the rat, like impact injury in the rabbit, is associated with a rapid and robust increase in the local spinal cord content and metabolism of 5HT and a long-term depletion of 5HT below the site of injury. The roles of the blood platelet and the raphe-spinal tract in the acute response and the disruption of axoplasmic transport during the chronic phase of injury are discussed.

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.45

年代:1991

数据来源: MAL

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.55

年代:1991

数据来源: MAL

ISSN:0897-7151    

DOI:10.1089/neu.1991.8.75

年代:1991

数据来源: MAL