Molecular level investigation of exocytosis in cultured human pheochromocytoma cells : insights from high resolution scanning electron microscopy combined with autoradiogram and cytochemistry  

作　　者：李英雄 周云英 

出　　处：《Chinese Medical Journal》1998年第4期8-14,共7页中华医学杂志（英文版）

摘　　要：Abstract Cardiovascular Department, Electron Microscopy Center, Chang Gung Memorial Hospital, Graduate Institute of Clinic Medicine, College of Medicine, Chang Gung University, Taipei, Taiwan, China (Lee YS and Chou YY) Reprint requests to: Dr. Ying Shiung Lee, Cardiovascular Department, Chang Gung Memorial Hospital, 199 Tung Hwa North Road, Taipei, Taiwan, China This work was supported by grants from Chang Gung Memorial Hospital Research Program, CMRP 419, Taiwan, China. Objective To investigate molecular events of exocytosis in cultured human pheochromocytoma cells with stimulation. Methods The cultured pheochromocytoma cells prepared from human adrenal pheochromocytoma tumor were stimulated for the release of catecholamines by depolarization with the administration of 50 mmol/L KCl. Transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HR SEM) combined with autoradiography and cytochemistry were used to observe molecular mechanisms of exocytotic release of catecholamines from the stimulated cells labelled with 3H noradrenaline and the filipin treated cells. Results TEM and HR SEM observations of the stimulated cells labelled with 3H noradrenaline revealed that the initial exocytotic fusion pores even less than 10 nm in diameter in human pheochromocytoma cells can be clearly observed in a single lipid bilayer. Furthermore, HR SEM examinations of the filipin treated cells showed that the derangement of the particles of the filipin sterol complexes (FSCs) in the fused membranes of granule and plasma membranes occurred as the exocytotic fusion pores opened. In addition, the aggreates of the FSCs particles were consistently demonstrated around the openings of the differently sized closing exocytotic pores. Conclusions Based on our results, it is suggested that the rearrangement of the sterol molecules in the fused membranes of granule and plasma membranes plays an important role in the opening and closing mechanisms of exocytotic fusion poresAbstract Cardiovascular Department, Electron Microscopy Center, Chang Gung Memorial Hospital, Graduate Institute of Clinic Medicine, College of Medicine, Chang Gung University, Taipei, Taiwan, China (Lee YS and Chou YY) Reprint requests to: Dr. Ying Shiung Lee, Cardiovascular Department, Chang Gung Memorial Hospital, 199 Tung Hwa North Road, Taipei, Taiwan, China This work was supported by grants from Chang Gung Memorial Hospital Research Program, CMRP 419, Taiwan, China. Objective To investigate molecular events of exocytosis in cultured human pheochromocytoma cells with stimulation. Methods The cultured pheochromocytoma cells prepared from human adrenal pheochromocytoma tumor were stimulated for the release of catecholamines by depolarization with the administration of 50 mmol/L KCl. Transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HR SEM) combined with autoradiography and cytochemistry were used to observe molecular mechanisms of exocytotic release of catecholamines from the stimulated cells labelled with 3H noradrenaline and the filipin treated cells. Results TEM and HR SEM observations of the stimulated cells labelled with 3H noradrenaline revealed that the initial exocytotic fusion pores even less than 10 nm in diameter in human pheochromocytoma cells can be clearly observed in a single lipid bilayer. Furthermore, HR SEM examinations of the filipin treated cells showed that the derangement of the particles of the filipin sterol complexes (FSCs) in the fused membranes of granule and plasma membranes occurred as the exocytotic fusion pores opened. In addition, the aggreates of the FSCs particles were consistently demonstrated around the openings of the differently sized closing exocytotic pores. Conclusions Based on our results, it is suggested that the rearrangement of the sterol molecules in the fused membranes of granule and plasma membranes plays an important role in the opening and closing mechanisms of exocytotic fusion pores

分 类 号：R73-3[医药卫生—肿瘤]