Age-related changes in the modulatory action of gastrin-releasing peptide,neuropeptide Y and sulfated cholecystokinin octapeptide in the proliferation of murine lymphocytes

Several investigations have suggested that the interactions between the ner vous and immune systems are modified with age. The aim of the present work was to study the effect in vitro of three neuropeptides: gastrin-releasing peptide (GRP), neuropeptide Y (NPY) and sulfated cholecystokinin octapeptid e (CCK-8s) on the spontaneous, as well as on the response to mitogen (conca navalin A), proliferative activity of spleen, thymus and axillary node leuk ocytes from adult (24 +/- 2 weeks), mature (50 +/- 2 weeks) and old (72 +/- 2 weeks) BALB/c male mice. In control samples, in the absence of neuropept ide, we observed a decreased lymphoproliferation in mature and old mice wit h respect to the adults in response to mitogen in the three organs studied. As regards, the effect of the neuropeptides, they stimulate the spontaneou s proliferation of leukocytes from all locations, in adult animals, an effe ct that is decreased with ageing tin both mature and old animals). The prol iferation in response to mitogen was significantly decreased by the neurope ptides in adults, this effect being progressively reduced with age.