Histamine Increased the Uptake of Rhodamine 123 in Mitochondria of Living Parietal Cells in Cultured Gastric Glands from Starved Guinea Pigs

Abstract

We previously found that parietal cells in guinea pigs starved for a few days contained giant mitochondria while the cells of animals starved and then injected with histamine mostly did not. To test whether mitochondria change their size and activity according to energy demands for acid secretion, we examined the dynamics of mitochondria stained by rhodamine 123 in living parietal cells in gastric glands under a confocal microscope. The glands were isolated from guinea pigs starved for 60-72 hr. Because mitochondria were closely packed in the cytoplasm, we failed to observe the morphological changes of each mitochondrion in parietal cells. However, we successfully observed that 10-5 M histamine induced an increase in the fluorescence intensity (the concentration of rhodamine 123) in mitochondria in subpopulations of parietal cells; the fluorescence intensity increased sharply within minutes after the histamine administration in some cells, while it gradually increased from just after the administration in other cells. We also found that a subpopulation of mitochondria within a parietal cell responded to the secretagogue. The findings suggest that parietal cells exist as a heterogeneous population in gastric glands and contain heterogeneous mitochondria in terms of their mitochondrial response to histamine.