Dopaminergic insufficiency reflecting cerebral ageing: value of a dopaminergic agonist, piribedil.

Amongst the various disturbances of neurotransmission accompanying cerebral ageing, dopaminergic insufficiency is undoubtedly the most constant, the earliest and the most severe. It affects the three ascending dopaminergic systems and may explain many of the motor, emotional, affective and cognitive disorders associated with cerebral ageing. In particular, the psychobehavioural syndrome of cerebral ageing is marked by disorders affecting the capacities for abstraction, conceptualization, reasoning, elaboration of strategies and problem-solving and therefore analogous to those of frontal symptomatology. They probably reflect disafferentation of the frontal lobe, deprived of effective dopaminergic innervation. This hypothesis is supported by the beneficial effects of the dopaminergic agonist piribedil on symptoms of cerebral ageing, particularly on the psycho-behavioural changes.