过度训练:不同发展阶段的神经内分泌变化

综述了关于过度训练状态下机体神经内分泌方面的变化,并对其中一些矛盾的结果提出了可能的解释。     

Role of bombesin-related peptides in the mediation or integration of the stress response

In addition to the relatively well established role of corticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP) in the mediation of the stress response, there is reason to believe that bombesin-like peptides (BN-LPs) may also contribute to the mediation or integration of these responses and thus might be considered as putative 'stress peptides'. This review provides evidence supporting this contention by showing that (i) BN-LPs are present at brain sites known to be activated by stressors, (ii) stressor exposure alters utilization of BN-related peptides, (iii) exogenous BN administration mimics the endocrine, autonomic and/or behavioral effects elicited by stressors, and (iv) antagonism of BN action attenuates the behavioral and/or neurochemical effects of stressors or of exogenously administered peptide. The evidence presented also suggests that BN-LPs mediate their stress-relevant effects through activation of CRH and/or AVP neurons. Several hypothetical mechanisms for such peptidergic interactions are discussed as to the implications of considering BN-LPs as 'stress peptides'. Received 16 July 2001; received after revision 27 August 2001; accepted 28 August 2001     

Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin. More than one-third of MCC patients will die from this cancer, making it twice as lethal as malignant melanoma. Despite the fact that MCC is still a very rare tumor, its incidence is rapidly increasing; the American Cancer Society estimates for 2008 almost 1 500 new cases in the USA. These clinical observations are especially disturbing as the pathogenesis of MCC is not yet fully understood; however, a number of recent reports contribute to a better understanding of its pathogenesis. Here we describe findings regarding the role of Wnt, MAPK and Akt signaling as well as possible aberrations in the p14ARF/p53/RB tumor suppressor network in MCC. Most important, and possibly with high impact on future therapeutic approaches is the demonstration that a polyomavirus has frequently integrated in the genome of the MCC cells prior to tumor development. Received 12 August 2008; received after revision 06 October 2008; accepted 22 October 2008     

新西兰家兔上唇皮肤麦克尔细胞的光镜和电镜观察

通过对成年新西兰免上唇皮肤麦克尔细胞(Merkel cell)及其与神经终末的光镜和电镜观察发现,麦克尔细胞多以成群分布在皮肤触盘上皮基底面和触须毛囊外根鞘,光镜下表现为明细胞,细胞长轴与表皮表面平行。电镜下这种细胞以胞质内存在特殊的直径80～200nm 的膜包致密核心颗粒为特征,核常分叶。胞体与周围角质形成细胞构成桥粒。神经纤维大量分布于毛囊外周和真皮,还见穿过基膜到达表皮和毛囊上皮鞘,与麦克尔细胞构成突触样结构。麦克尔细胞质内的特殊颗粒多集中在此结构附近。此外,可见兼有角质形成细胞和麦克尔细胞某些特征的过渡细胞,其胞质既含有麦克尔颗粒,又含有粗的张力丝。实验结果提示麦克尔细胞可能是一种神经内分泌细胞,可能由上皮内角质形成细胞发育而来。