Distribution of calcitonin gene-related peptide-containing fibers in the urinary bladder of the rat and their origin |
| |
Authors: | Kiyoshi Yokokawa Dr. Masaya Tohyama Sadao Shiosaka Yahe Shiotani Takao Sonoda Piers C. Emson Calmer V. Hillyard Samia Girgis Iain MacIntyre |
| |
Affiliation: | (1) Department of Anatomy, Kagawa Medical School, Kagawa, Japan;(2) Department of Anatomy, Kagawa Medical School, Miki, 761-07 Kagawa, Japan |
| |
Abstract: | Summary Using horseradish peroxidase (HRP) as a tracer, we have investigated if the so-called apical tubules (AT) in the kidney proximal tubule cells are directly involved in the endocytic process by carrying the tracer into the cells, or if they are derived from the intracellular membrane compartments. Rat kidney was fixed by vascular perfusion at different time intervals after intravenous injection of HRP and prepared for electron microscopy. An analysis revealed that 0.5 min after injection, invaginations of the plasma membrane and small apical endocytic vesicles, including coated vesicles, were labelled with reaction product, whereas almost all large apical endocytic vacuoles and the AT were negative. The endocytic vacuoles and about 18% of the AT were labelled 1 min after injection. The reaction product in the large endocytic vacuoles was usually seen along the luminal surface of the vacuoles. The AT with reaction product appeared as a branched network, and were frequently connected with the labelled endocytic vacuoles. Three min after injection, reaction product was detected in about 38% of the AT, and thereafter, the percentage increased to about 74% after 7 min. No reaction product was detected in the Golgi complex at any time after HRP-injection. These findings indicate that the AT are probably formed by budding off from the large endocytic vacuoles, rather than being directly involved in the endocytic process. |
| |
Keywords: | Endocytosis Absorptive cells Kidney (proximal tubule cells) Apical tubules Membrane recycling Rat |
本文献已被 SpringerLink 等数据库收录! |
|