The Effects of Single Doses of Pilocarpine and of Histamine upon the Granules of Oxyntic Cells of Rats , with Special Reference to their Phospholipine Content

1. New data are presented on the morphology and cytochemistry of the granules of the oxyntic cells of the rat's stomach in continuation of work previously reported (Menzies, 1949). The effects of single injections of pilocarpine and of histamine on the granules were investigated, with particular reference to their phospholipine content as shown by Baker's acid haematein method. 2. Pilocarpine causes a marked enlargement of the granules with loss of phospholipine from the central part of many of the larger granules, and complete loss of phospholipine from others. The granules that have lost their phospholipine probably still contain lipoid as shown by sudan black. Pilocarpine also causes marked aggregation of the granules. 3. Histamine causes a less marked increase in granule size and no observable loss of phospholipine, but some of the granules became elongated, an effect that can be seen with the phase-contrast microscope, and there is a tendency for them to recede to the peripheral parts of the cells associated with an enlargement of the intracellular canals. 4. Both pilocarpine and histamine result in some enlargement of the oxyntic cells, the effect being more marked with pilocarpine. 5. Neither pilocarpine nor histamine alters the size or shape of the non-lipoid moiety of the granules. 6. Supravital colouring with neutral red shows a few droplets in oxyntic cells in the bases of the gastric glands. These enlarge slightly after histamine and greatly after pilocarpine, and they are always spherical. It has not yet been possible to decide as to their exact nature.