International Journal of Comparative Psychology

The present review is concerned with the biological role(s) exerted by Growth Factor (GF) protein molecules in adult rodents. In fact, despite the increasing amount of papers published in the last two-three decades about the physiological roles played by Nerve GF and Epidermal GF (as well as by related polypeptide molecules) on the ontogenesis of rodent peripheral and central nervous systems, very little attention has been given to adult regulations involving these two factors. We here report about our studies concerning the biological significance of the huge quantity of NGF stored in the submaxillary salivary glands of the adult male mouse. When released into the bloodstream as a result of psychosocial stress, salivary NGF affects peripheral nervous structures (chromaffine cells and ganglia) and peritoneal mast-cells. Following psychosocial stress, NGF production is enhanced in specific hypothalamic zones. Adult regulations regarding the concomitant EGF release from salivaries are also discussed.