IN-VIVO MICROSCOPY OF THE EXOCRINE PANCREAS

Light microscopic studies of the living acinar pancreas, although limi ted in number, have revealed valuable information concerning dynamic a spects of microvascular and parenchymal structure and function. For ex ample, it has been found that: 1) the living organ in anesthetized ani mals can be imaged with a resolution approaching the limit of the ligh t microscope; 2) blood flow through individual capillaries in the exoc rine pancreas is intermittent; 3) blood flow through these capillaries is regulated locally by smooth muscle precapillary sphincters and wit hin individual capillaries by endothelial cells which are spontaneousl y contractile as well as responsive to vasoactive substances; and 4) t ile formation and release of zymogen granules occurs within 45-90 minu tes in acinar cells stimulated with pancreozymin. This paper reviews t hese studies and some of the methods used to obtain them. (C) 1997 Wil ey-Liss, Inc.