EN
Even if it is suggested that stress does not directly induce cancer there is plenty of evidence that shows that stress represents an important factor facilitating cancer progression, however the exact mechanisms and pathways are not known in details. Because the autonomic nervous system plays an important role in the elaboration of stress response, we investigated the effect of the disruption of the sympathetic or parasympathetic system on the survival of tumor bearing rats. We used male Wistar rats in which we performed either chemical sympathectomy induced by intraperitoneal application of 6-OH dopamine or subdiaphragmatic vagotomy by surgical dissection of the vagus nerve. After a regeneration period we administered intraperitoneally to sympathectomized, vagotomized and sham operated rats Yoshida ascites cells. We have found that whereas chemical sympathectomy signifi cantly reduced the survival of tumor bearing rats, subdiaphragmatic vagotomy had only a slight effect on reducing the survival of rats implanted by Yoshida cells. Our fi ndings suggest that the autonomic nervous system, especially its sympathetic division, plays an important role in the regulation of the development of Yoshida ascites tumor cells in rats. We suggest that whereas long lasting sympathetic activation as a consequence of exposure to chronic stress might have a promoting effect on cancer growth, the sympathetic system might have, during basal conditions, a modulatory effect on tumor progression.