Figure 5.

Serous cells of parotid gland exposed to isoprenaline for 10 min and used for the immunogold localisation of melatonin. Melatonin reactivity (transparent arrows) was observed in the lumen (L) and in omega exocytosis profiles (*). Reactivity was also observed in membranes (arrowhead) and in the matrix of persisting granules (black arrows), as well as in the rough endoplasmic reticulum (white arrowhead) and in the nucleus (white arrows). Compared with the unstimulated contralateral gland, the isoprenaline‐stimulated gland had lost 25% of its content of acinar secretory granules. N, nucleus. Scale bar: 1 μm.