Treatment with L-dopa in early life restored pituitary-adrenocortical response to emotional stress in adult rats with inherited arterial hypertension.

This study investigates the function of the hypothalamic-pituitary-adrenocortical system (HPAS) in adult rats with inherited stress-induced arterial hypertension (ISIAH rats) whose arterial blood pressure was lowered by the dopamine precursor L-DOPA treatment during early development (on days 21-25 of life). The response of the HPAS induced by emotional stress was significantly lower in intact ISIAH rats than in normotensive Wistar animals. Injections of L-DOPA on days 21-23 or 21-25 of postnatal life were followed by a long-lasting complete restoration of the emotional stress response in adult ISIAH rats. The restoring effect of L-DOPA was produced through enhancement of synthesis of the brain noradrenaline and, perhaps, adrenaline. The effect was associated with a normalization of the response of the brain adrenergic system to noradrenaline and did not relate to an increase of the plasma corticosterone level after L-DOPA administration in early ontogeny.