Nitric oxide mediates long-term potentiation in rat superior cervical ganglion

Long-term potentiation (LTP) of the nicotinic pathway of the superior cervical ganglion (SCG) is remarkably similar to that of the hippocampus which has been shown to involve nitric oxide (NO). We investigated a similar possible involvement of NO in the LTP of the SCG of the rat. Treatment of ganglia with the NO-synthase inhibitor N^G-nitro-l-arginine (l-NOARG, 10 μM) blocked LTP at the maintenance phase. © 1997 Elsevier Science B.V. All rights reserved.     

Agonist desensitisation of α1 adrenoceptors and endothelin-1 receptors coupled to phosphatidylinositol metabolism

Summary— Agonist desensitisation of responses coupled to phosphatidylinositol metabolism were studied. Responses mediated by two different agonists, endothelin-1 and noradrenaline were investigated. In vivo pressor responses were examined in conscious male New Zealand white rabbits, while effects on inositol phosphate formation were studied in rings of freshly isolated aorta and in cultured aortic vascular smooth muscle cells. No desensitisation of responses to noradrenaline were observed in vivo despite a 10-day infusion under conditions which cause desensitisation of α₂ and β-adrenoceptor mediated responses. In contrast, responses to endothelin-1 were attenuated within 5 min of commencing endothelin-1 infusions. No reduction in noradrenaline stimulated inositol phosphate was observed in cultured vascular smooth muscle cells after pre-incubation with noradrenaline up to 10⁻⁴M, whereas with endothelin-1 pre-incubation a dose and time-related reduction in endothelin-1 stimulated inositol phosphate formation was observed. Thus, differences in the pattern of desensitisation of both pressor responses and phosphatidylinositol metabolism were observed for noradrenaline and endothelin-1 suggesting that the nature of the 2nd messenger involved in signal transduction is not the only determinant of agonist desensitisation. In addition, differences in the rate of desensitisation and sensitivity to endothelin-1, but not noradrenaline, were observed when responses in cultured cells were compared with in vivo responses or responses to freshly isolated tissues. These differences are discussed in relation to possible modifications of the endothelin receptor or its coupling to phosphatidylinositol metabolism during culture.     

查耳酮类化合物对过敏性慢反应物质拮抗作用的构效关系

查耳酮类化合物对过敏性慢反应物质拮抗作用的构效关系何克勤，程桂芳，奚凤德，郭宗儒，朱秀媛（中国医学科学院，中国协和医科大学药物研究所，北京１０００５０）过敏性慢反应物质（ＳＲＳＡ），主要含白三烯Ｃ４（ＬＴＣ４）、白三烯Ｄ４（ＬＴＤ４）和白三烯Ｅ４（Ｌ...     

Survey of seven plasma protein polymorphisms in the Amhara and Oromo populations of Ethiopia

The Ethiopian population is very difficult to specify due to a very high degree of intermixing among different peoples. The two groups of the present study, the Amhara and Oromo, constitute 38% and 35% of the population, respectively. In order to investigate the genetic composition of the Amhara and Oromo, genetic polymorphisms of seven plasma proteins (F13A, F13B, ORM1, AHSG, C6, C7, and APOC2), already identified as useful anthropological markers, were studied. No statistically relevant differences were found between the two groups for all of the systems examined. ORM1 and F13A showed frequencies in the range observed in other populations of Caucasoid and Negroid origin. F13B, AHSG, and C6 displayed gene frequencies and a number of variant alleles that seem particular to these two groups. No variation was observed for C7 and APOC2. Correspondence and distance analyses were used to interpret and compare the gene frequencies of the Amhara and Oromo with those of other related populations. These methods locate Ethiopians in an intermediate position between African Blacks and a group of Caucasoid populations, confirming cultural and historical data. © 1994 Wiley-Liss, Inc.     

Adventitial cystic disease of the popliteal artery

Adventitial cystic disease of the popliteal artery is an unusual condition of uncertain etiology in which a mucin-containing cyst forms in the wall of the popliteal artery and causes symptoms of intermittent claudication, typically in young adults whose arteries are otherwise normal. Arteriography characteristically shows a smooth-walled, curvilinear narrowing. In the case described, a combination of findings from arteriography, computed tomography, and ultrasound resulted in a highly specific preoperative diagnosis.