Theoretical considerations on the nature of the pineal 'ageing clock'.

The models developed in our laboratory demonstrate that ageing initiates and progresses in the pineal gland. However, the ageing postponing effects of pineal grafting into older recipients cannot be explained by a simple maintenance and/or normalization of the night melatonin synthesis and release. We propose here that the pineal gland monitors and regulates, via its control of neuroendocrine function, the maintenance of 'self-identity' and the capacity of the immune system to recognize and react against any noxious, endogenous or exogenous agent. Senescence is characterized by the extinction of this central pineal function. The progressive decline of the self-recognition capacity distinguishes the typical diseases of ageing expressed as emergence of peripheral desynchronization and autoimmune, anaplastic, neoplastic and degenerative processes. Our approaches aim at a prevention and/or restoration of central pineal functions.