Electron Microscope Studies on the Gastric Chief Cells of Hibernating Bats (<i>Rhinolophus ferrum-equinum nippon</i>)

Abstract

Thanks to recent progress of electron microscopy and efforts of many investigators, the fine structure of the gastric mucosa has been gradually elucidated. Later and HELANDER (1964) made experimental observations on the gastric gland in unfed and refed rats and mice. Most of the previous studies, however, were performed chiefly to elucidate the fine structure of the parietal cell under normal and experimental conditions, whereas the chief cells, which are considered to secrete pepsin, were studied only peripherally in the course of work on the gastric mucosa as a whole. The present work was carried out on the bat gastric mucosa to resolve some unanswered problems concerning the fine structure of the chief cell in the hibernating period. I. Materials and Methods.Bats (Rhinolophus ferrum-equinum nippon) of both sexes, weighing between 10-20g, were used in the present study. They were all captured in the same area of Gunma Prefecture during their hibernating period, killed by sudden decapitation without anesthesia; after immediate opening of the abdomen, a small amount of cold fixative was dropped into it, and the whole stomach taken out. It was cut open along the greater curvature and dipped into the fixative: a 1% osmium tetroxide solution adjusted to pH 7.4 with veronal-acetate buffer and rendered isotonic by adding sucrose according to CAULFIELD's method (1957). A small portion of the gastric mucosa was promptly cut off along the lesser curvature at a short distance from the pylorus, and then cut into many smaller pieces with razor blades in the fixative. These were kept in a small bottle of the fixative in a refrigerator for about 90 minutes at about 389