<title>Real-time imaging of the living kidney juxtaglomerular apparatus with multiphoton microscopy</title>

Abstract

The process of glomerular filtrate formation and regulation of renal hemodynamics, including the tubuloglomerular feedback (TGF) mechanism from the macula densa (MD) and renin release, involves the complex interaction of a number of different cell types of the juxtaglomerular apparatus (JGA). It has been difficult to study these cellular interactions in living preparations given the constraints of existing technologies. Recently, two photon confocal laser microscopy has been developed that offers a tremendous increase in optical resolution versus conventional confocal microscopy. Importantly it can optically section through an entire glomerulus (glomerular diameter approximately equals 100 micrometers ). Thus, it provides the ability to directly study structures and cellular components that lie deep within the glomerulus. This new technology was used in our studies. We now report high-resolution images of various glomerular and JGA cells using the membrane-marker TMA-DPH and the calcium fluorophore indo-1. Time-series images show how alterations in tubular fluid composition cause striking changes in single cell volume of the macula densa tubular epithelium in situ and how it also affects glomerular filtration through alterations in associated structures within the JGA. Multi-photon excitation fluorescence microscopy in combination with isolated perfused JGA offers a powerful new tool to investigate the structural and cellular components that regulate the process of glomerular filtrate formation and renal hemodynamics.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.