银杏叶制剂和丹参对急性肾衰兔肾皮质局部血流量的影响

目的探讨急性肾功能衰竭(acute renal failure,ARF)兔肾皮质局部血流量(regional renalblood flow,rRBF)与血液流变学的关系,以及银杏叶制剂(Ginkgo Bilobal Extraction,GbE)、丹参对其的影响.方法用50%的甘油10 ml/kg行兔后肢肌肉加压注射,建立ARF动物模型,观察血液流变学、rRBF的变化,并给予GbE、丹参注射液对比观察.结果 ARF组血液流变学指标明显异常,rRBF明显下降.ηb、ηb、EAI、HCT等与rRBF呈明显负相关(P均＜0.05).GbE组、丹参组动物血液流变学、rRBF等指标明显改善.结论 ARF时血液流变特性恶化和肾局部微循环障碍可能是造成rRBF下降的直接原因之一.GbE、丹参对甘油所致ARF家兔的血液流变特性及肾组织缺血性损害有明显的保护作用.     

Fibre type specific expression of Leu19-antigen and N-CAM in skeletal muscle in various stages after experimental denervation

Leu-19 antigen, which seems to be identical with neural cell adhesion molecule (N-CAM), plays a major role in the innervation of muscle cells, and in adult muscle appears after denervation and during regeneration of muscle fibres, where it acts as part of a signalling system increasing the probability of re-innervation. This combined enzyme-histochemical and immunohistochemical study examined whether this signalling process was regulated in a uniform or differential pattern for type 1 and type 2 muscle fibres. The subscapular nerve of 18 rabbits was transsected with subsequent complete denervation of the supraspinatus muscle. Leu19 and N-CAM immunohistochemistry was performed 2 to 64 days after surgery. Whereas in normal muscle there are virtually no Leu-19/N-CAM positive muscle fibres; from day 2 after denervation an increasing proportion of fibres expressed Leu-19/N-CAM, prior to any neurogenic atrophy. In the early stage of denervation Leul9/N-CAM expression was confined to type 1 fibres. After 11 days nearly all fibres were Leul9/N-CAM positive irrespective of their fibre type. Sixty-four days after denervation type 1 fibres became Leu19/N-CAM negative, while atrophic type 2 fibres showed intensive staining. Thus, expression of Leu-19 antigenity is differently regulated in both fibre types.     

含辛伐他汀药物血清对兔血管平滑肌细胞增殖的直接作用及意义

目的 :探讨辛伐他汀对体外培养兔血管平滑肌细胞增殖的影响及意义。方法 :16只雄性新西兰兔随机分为血清对照组和三个不同剂量的辛伐他汀亚组 (每日分别给予辛伐他汀 5mg/kg、10mg/kg、15mg/kg) ,7天后采血并混合每组 4只兔血 ,无菌分离制备三亚组的辛伐他汀含药血清。采用内皮素 1(ET 1)刺激正常喂饲原代培养兔主动脉血管平滑肌细胞的方法 ,建立血管平滑肌细胞增殖模型。采用MTT及3H TdR法检测各组辛伐他汀含药血清对血管平滑肌细胞增殖的作用。结果 :与不含药的正常对照组相比 ,不同亚组辛伐他汀含药血清呈剂量依赖性抑制血管平滑肌细胞增殖 (P <0 .0 1～0 .0 5 )。结论 :兔口服辛伐他汀后的血清具有抑制血管平滑肌细胞增殖的作用     

Fatty acid synthesis in the arrested rabbit heart during ischemia

In rabbit hearts arrested by a carnosine-buffered cardioplegic solution the incorporation of [1-¹⁴C]acetate into lipids was investigated. After 10–20 and 60 min of ischemia the radioactivities of phospholipids, mono-, di-, and triacylglycerols, acyl-CoA, acylcarnitine, and free fatty acids were determined. In the first period of ischemia mainly acylcarnitine was labelled (ca. 50%) and only 25% of [¹⁴C]-activity was found in phospholipids which showed the lowest specific activity of all lipid classes. After 60 min of ischemia the percentage of total radioactivity of acylcarnitine and phospholipids was decreased, whereas that of neutral lipids was increased to more than 50%. During the increase of total radioactivity the relative specific activity of all lipids decreased except that of triacylglycerols. Only fatty acids up to chain lengths of 16 carbon atoms were labelled. Lauric and myristic acid had high specific activities. These results indicated de novo synthesis of fatty acids accumulating in triacylglycerols during ischemia of the arrested heart.     

Intracellular recordings from isolated rabbit retinal Müller (glial) cells

Müller (glial) cells were isolated from rabbit retinae by papaine and mechanical dissociation. The cells were fixed on a gelatine-covered glass slide by means of concanavalin A, and the slide was mounted in a perfusion chamber under a light microscope with modified optics. Besides the recording microelectrode, two other micropipettes could be adjusted with their tips near the cell. These micropipettes were used for application of test solutions into the environment of the cells. On application of high K⁺ solutions, the cell depolarized strongly but during prolonged application there was a marked repolarization. After the end of high K⁺ application the cells showed a hyperpolarization which was enhanced in both amplitude and duration with prolongation of the K⁺ exposure. Both repolarization and afterhyper-polarization disappeared under ouabain. Ouabain application itself caused a small reversible depolarization. Na⁺ free solution caused hyperpolarization. The results suggest the existence of an active membrane pump mechanism in our cells. This pump seems to be electrogenic under our experimental conditions and seems to be activated even in the absence of sodium. The cell membrane is demonstrated to contain a significant Na⁺ conductance.     

The membrane potential of vascular smooth muscle appears to modulate uptake2 of 3H-isoprenaline

Summary Segments of the rabbit main pulmonary artery and of its two branches were exposed for 10 min to 50 nmol/l ³H-(±)-isoprenaline, and the accumulation of tritium in the tissue was determined; COMT was inhibited in all experiments. 1. The accumulation of the tritium label was sensitive to 3-O-methyl-isoprenaline (OMI), showing that this vascular smooth muscle possesses uptake₂. 2. In the presence of 0.01 to 1 mol/l (–)-noradrenaline, the accumulation of tritium was depressed (in a concentration-dependent manner). This decline involved the OMI-sensitive accumulation of ³H-isoprenaline. 3. The presence of any one of three selective alpha₁-adrenoceptor antagonists (1 gmol/l prazosin, 1 mol/l WB4101, 10 gmol/l corynanthine) prevented the effect of 1 mol/l (–)-noradrenaline on the accumulation of tritium. However, in the absence of (–)-noradrenaline, the three antagonists failed to affect the accumulation of tritium. 4. 10 mol/l nicorandil caused the accumulation of tritium to increase. 5. As stimulation of alpha₁-adrenoceptors is known to result in depolarization, and as nicorandil is known to hyperpolarize this smooth muscle, it is concluded that the resting membrane potential modulates uptake₂. Send offprint requests to U. Trendelenburg at the above address     

Polymyxin B,a selective inhibitor of protein kinase C,diminishes the release of noradrenaline and the enhancement of release caused by phorbol 12,13-dibutyrate

Summary Slices of the rabbit hippocampus were labelled with ³H-noradrenaline, superfused continuously with a modified Krebs-Henseleit medium containing the uptake inhibitor cocaine and stimulated electrically (2 ms, 3 Hz, 24 mA, 5 V/cm). Phorbol 12,13-dibutyrate (PDB), a potent activator of protein kinase C (PKC), strongly enhanced the electrically-evoked overflow of tritium. In contrast, polymyxin B, a relatively selective inhibitor of PKC, diminished the evoked tritium overflow in a time-and concentration-dependent manner. The enhancement of the evoked overflow of tritium caused by PDB was strongly reduced in the presence of polymyxin B (100 mol/l). These results suggest 1. that PKC may be involved in the physiological mechanism of action-potential-induced noradrenaline release from noradrenergic nerve terminals and 2. that the PDB-induced enhancement of noradrenaline release may be due to a direct activation of PKC.Abbreviations PKC protein kinase C - PDB phorbol 12,13-dibutyrate - TPA 12-O-tetradecanoyl 13-acetate     

Facilitating interaction between rauwolscine and angiotensin in the mesenteric artery of the rabbit

Summary The interaction between rauwolscine and angiotensin II was investigated in the isolated mesenteric artery of the rabbit. Rauwolscine, known as an antagonist at ₂-adrenoceptors, did not induce contraction itself but interacted with angiotensin to produce a facilitated response of the vascular tissue. In the presence of rauwolscine, the contractile response of the tissue to angiotensin was markedly enhanced. The degree of facilitation appeared to be dependent on the rauwolscine concentration used rather than that of angiotensin. Moreover, rauwolscine induced a concentration-dependent increase in tension (pD₂=6.8) in the presence of even subcontractile concentrations of angiotensin (10^–10 mol/l). This effect was not attributable to an indirect action involving presynaptic catecholamines, as revealed by the use of tissue strips from animals pretreated with reserpine or after chemical sympathectomy. Furthermore, an interaction via the prostaglandin system was excluded by negative results obtained with indomethacin. The agonistic effect of rauwolscine was significantly attenuated by phentolamine (₁/₂) but not by prazosin (₁) or phenoxybenzamine when applied for only a short time. The ₂-antagonist BDF 6143 behaved like rauwolscine whereas the ₁-antagonist corynanthine, a stereoisomer of rauwolscine, did not. The results indicate that the rauwolscine effect is mediated by a receptor with ₂-characteristics. In general, angiotensin appears to interfere with some process which determines the expression of a drug's intrinsic effect.This study was supported by a grant of the Deutsche Forschungsgemeinschaft     

脉络宁对骨内高压血液流变学的影响

目的 观察脉络宁对骨内高压时血液流变学指标的影响。方法 将家兔一侧后肢于膝关节伸直接固定5周,造成固定侧胫骨上端骨内高压模型,测定血液流变学指标,与静脉注射脉络宁2周后血液流变学指标进行比较。结果 骨内高压时全身静脉血和骨髓血粘度均明显升高;给予脉络宁治疗2周后,其静脉血和骨髓血粘度明显降低,同正常组相比差异无显著性（P＞0．05）。同时,骨内压明显下降。结论 脉络宁可通过改善全身和局部血液流变学指标,纠正骨内循环动力异常,降低骨内高压。     

酸血症对有机磷农药中毒家兔模型阿托品化量影响的实验研究

目的：探讨酸中毒对有机磷农药中毒病人阿托品化量的影响。方法：采用家兔80只,随机分为两组,一组制造酸血症模型,另一组对照,两组均注射公斤体重相同剂量的有机磷农药,制造有机磷农药中毒模型,而后用阿托品解救,并达到阿托品化状态,比较两组阿托品的用量。结果：酸血症组阿托品用量明显高于对照组。结论：有机磷中毒病人合并酸中毒时,阿托品化量,高于正常。及时纠正酸中毒, 有利于有机磷中毒患者的治疗。