An ultrastructural study of salivary gland radiosensitivity after alpha-adrenergic stimulation.

The submandibular glands in 32 rats were exposed to either fractionated irradiation comparable to 50 Gy or a single fraction of 50 Gy. Prior to irradiation half the rats were given cyclocytidine, an alpha-adrenergic agonist which depletes serous cell granules. The results suggest that irradiation causes a significant, irreversible destruction of serous cells. Visible morphological changes were: intracytoplasmic vacuoles, destroyed mitochondria with disrupted cristae and derangement of the endoplasmic reticulum. Animals treated with cyclocytidine had diminished radiation injury. This drug may act as radioprotector, depleting secretory heavy metal granules, reducing radiation damage in the submandibular salivary glands.