远曲小管闰细胞和入球微动脉的直接接触：小鼠肾脏数字化三维重建.docVIP

  Direct Physical Contact between Intercalated Cells in Distal Convoluted Tubule and the Afferent Arteriole in Mice# REN Hao, Xiaoyue Zhai* 5 10 15 20 25 30 35 40 (china medical university, histology and embryology) Abstract: IDirect physical contact between the distal tubule and the afferent arteriole has been reported in rats and rabbits. The existence of a feedback mechanism termed cross-talk similar to that at macular densa has been proposed, which has significant impact on the control of systemic acid-base and electrolytes status. In the present study, we applied computer assisted 3D nephron tracing combined with immunohistochemistry to investigate such contacts in mice. With tracing, it became possible to determine whether the tubule and the contacting arteriole were associated to the same parent nephron or not. We investigated a total of 168 nephrons from 3 mouse kidneys. The majority of the nephrons (approximately 90% of the short-loop and 75% of the long-loop nephrons) had direct physical contact between their own afferent arteriole and distal tubule. These contacts always occurred at the last 10% of the distal convoluted tubule. Type nonA-nonB intercalated cells were always found in the tubular wall at the contact site. In conclusion, the present work demonstrated the existence of direct tubule-arteriole contact in mice. The close association of intercalated cells in the distal convoluted tubule suggests that these contacts may be the morphological basis for a cross-talk mechanism, which is potentially involved in the post-macula densa humeral pH and electrolyte regulation in the kidney. Key words: histology and embryology; 3D digital reconstruction; mouse kidney 0 Introduction One classical mechanism for control of the glomerular filtration rate (GFR) is the tubuloglomerular feedback mechanism at the macula densa (MD). Upon increases in tubular NaCl concentration at the MD, the afferent arteriole (Af-Art) constricts resulting in a rapid decrease in GF