RESUMO
We examined the effects of irradiation over the thorax of the rat on the mast cells, the neuropeptide-containing nerve fibers, and the expression of atrial natriuretic peptide in the heart and lung. The total doses were 20 to 36 Gy delivered as single doses or fractionated irradiation. Immunohistochemical and radioimmunoassay methods were used. The number of mast cells was much reduced in both the lung and heart in response to irradiation. A trend for lowering the atrial natriuretic peptide levels in plasma was noted both 1 day and 9 days after irradiation. In contrast to the situation in other organs (salivary and laryngeal glands, the intestine), no changes occurred in the immunohistochemical expression of neuropeptides. With these observations and those made in previous studies about the effects of radiotherapy on other organs, the functional significance and basis for further research in the fields are discussed.
