RESUMO
The neural formations of intact rabbit major arteries and nerves of the same arteries in rabbits with the II and IV stages of the malignant Brown--Pearce tumor have been studied. Periarterial neural fasciculi, fibers and terminal branches have been revealed. According to ultrastructure of their cytoplasmic matrix, they can be divided into adrenergic, cholinergic or sensitive. When the malignant tumor is growing, the arterial neural formations undergo certain distrophic-destructive changes; they are especially pronounced in the membranous structures of the neural elements. Their cytoplasmic and basal membranes are partly or completely destroyed. In mitochondria the matrix is altered, some of them are vacuolized. Neurotubules and vesicles change their form and size and are partly destroyed. Membranous structures of lemmocytes are altered. The electron microscopic investigation adds something new to our data on ultrastructural changes in the arterial neural formations under growth of the malignant tumor previously obtained by means of neurohistological and neurohistochemical methods.