Effect of aging on the modulation of macrophage functions by neuropeptides

The existence of a functional connection between the nervous and the immune system is supported by increasing recent evidence. In previous work we hav e shown that peptides from the nervous system, such as gastrin-releasing pe ptide (GRP), neuropeptide Y (NPY) and sulfated cholecystokinin octapeptide (CCK-8s), have modulatory effects on the immune functions in adult animals. Since the immunodepression found in aging organisms may be related to chan ges in the neuroimmune network, the aim of the present work was to study th e changes with aging in the effect of CCK-8s, GRP and NPY on peritoneal mac rophage functions (adherence to tissues, mobility, ingestion of foreign par ticles and superoxide anion production) from BALB/c mice of three different ages: adult (24+/-2 weeks old), mature (50+/-2 weeks old) and old (72+/-2 weeks old). The results show that the increase in adherence capacity produc ed by neuropeptides in cells from adult and mature animals disappears in ol d mice. The stimulatory effect of GRP and NPY on mobility, ingestion and su peroxide production in macrophages from adult mice disappears (GRP) or chan ges to inhibition (NPY) in cells from old animals. The decrease of these fu nctions caused by CCK-8s in adult or mature animals continues in old mice. These data suggest that the modulation by neuropeptides of the macrophage f unction changes with the age of animals, (C) 2000 Elsevier Science Inc. All rights reserved.