Figure 1

Immunocytochemical staining of myenteric neurons cultured in absence (A) or presence (B-F) of peritoneal mast cells. A. Neurons grown for 6 days and stained with PGP9.5. The cultured neurons survive well; they group into ganglion-like structures and grow a prominent arborizing network of nerve terminals. B. Neurons co-cultured with mast cells (arrows) stained with antibodies against PGP9.5 and histamine, respectively. In the neuronal cultures to which mast cells have been added the number of neurons markedly decreases and the terminal network is disintegrated. C and D. show mast cells grown in co-culture and stained with histamine antibodies. The mast cells are well settled within the cultures and they contain a high number of cytoplasmic granules. C. illustrates a cultured mast cell with numerous granules in the central, perinuclear, portion of the cell. D. shows a mast cell exhibiting piece meal degranulation. E and F. illustrate the morphological relationship of cultured neurons and mast cells. E. shows mast cells (arrowheads) in close contact with nerve terminals from nearby myenteric neurons (arrows). F. a mast cell and a nerve cell body in close proximity. In order to perceive the morphological arrangement of mast cells and neurons both PGP9.5- and histamine- immunoreactive cells are visualised by FITC conjugated antibodies. Neurons and mast cells are distinguished by their morphological characteristics. Bar in A 100 μm represents also B, bar in C 40 μm represents also D, bar in E 50 μm represents also F.