苯丙胺诱发小鼠激怒反应及其机制

苯丙胺15mg/kg ip能诱发小鼠激怒反应,使小鼠出现攻击和殴斗行为。强安定药、弱安定药和利血平有明显拮抗效果。镇静剂如巴比妥类、抗胆碱药及抗肾上腺素药均无拮抗作用。金刚胺、左旋多巴和阿扑吗啡均能增强苯丙胺的激怒效应。因苯丙胺激怒小鼠的方法简便易行,可作为筛选抗精神病药的动物模型。苯丙胺产生激怒作用的机制与增强多巴胺能神经的功能有关,推测可能是促进边缘系统多巴胺释放的结果。     

Nordihydroguaiaretic acid inhibits voltage-activated Ca2+ currents independently of lipoxygenase inhibition

The effects of nordihydroguaiaretic acid (NDGA), a widely used lipoxygenase inhibitor, were examined on voltage-activated Ca2+ channel currents in GH3 and AtT-20 pituitary cells. NDGA (10-100 microM) produced a reversible, dose-dependent inhibition of Ca2+ channel currents, with half-maximal inhibition occurring at 18.6 microM. Inhibition by NDGA developed relatively slowly, did not exhibit use dependence or voltage dependence, and did not require access of NDGA to the extracellular domain of the Ca2+ channel. The maximum inhibition of macroscopic currents by 30 microM NDGA was equivalent in the presence of 5 and 50 mM extracellular Ca2+ and 5 mM Ba2+. NDGA inhibited Ca2+ channel currents in excised, outside-out patches, in the absence of intra- and extracellular Ca2+ (with Ba2+ as the charge carrier), and following preincubation of the cells with the phospholipase A2 inhibitor 4-bromophenacylbromide. Of five other lipoxygenase inhibitors tested, only one inhibited Ca2+ currents. These results suggest that NDGA inhibits Ca2+ channel currents by a mechanism distinct from that of other known Ca2+ channel antagonists and that, when influx of Ca2+ through voltage-gated channels is involved, inhibition of Ca2(+)-dependent cell functions by NDGA (greater than 10 microM) may be independent of effects on arachidonic acid metabolism.     

Clinical evaluation of a new epidural pressure monitor

Summary Comparative measuring of epidural pressure using the Spiegelberg probe 1 and ventricular fluid pressure was carried out in 15 neurosurgical intensive-care patients. Deviations in both directions were established, with a trend toward overestimating ventricular pressure in epidural pressure measuring (r=0.77). Individual pulsations, spontaneous wave courses and therapy-induced pressure changes were reflected without delays. There were no complications observed with probe implantation periods for up to 6 days. The system has been shown to be mechanically stable and easy to implant. We believe the device to be fit for trend monitoring of intracranial pressure. As with other epidural pressure monitoring systems, false assessments of ventricular pressure may lead to wrong decisions as to the required therapy.     

Patellofemoral joint: kinematic MR imaging to assess tracking abnormalities

The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0 degrees to 32 degrees of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationship of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities.