Effects of L-3,4-dihydroxyphenylalanine (L-Dopa) Treatment in the Neuroendocrine Response to Stress

Abstract Stressful stimuli evoke a complex response mediated by two systems: the Sympathetic-Adreno-Medullar (SAM) axis and Hypothalamus-Pituitary-Adrenal (HPA) axis. Among factors involved in stress, glucocorticoids catecholamines secreted from adrenal glands sympathetic nerves are main effectors of physiological adaptations to stressors. Besides these, prolactin (PRL) is another hormone under stress conditions. Catecholamines synthesized hydroxylated precursor L-Dopa. This agent commonly used for treatment Parkinson’s disease it would act as neurotransmitter per se. On other hand, has been suggested that HPA dysregulation potential risk factor development depression. In line with this, several studies reported L-Dopa may alter serum levels ACTH, PRL, parkinsonian patients animal models. present study, we determined whether chronic altered inducing depressive-like behaviours. Adult male Wistar rats were treated orally during 24 days LEBOCAR® - commercial formulation (75 mg/day) Carbidopa (7.5 drinking water. Animals stressed immobilization last 9 behaviours assessed sucrose intake forced swimming tests. Behavioural tests showed no signs LEBOCAR®-treated and/or rats. We next explored SAM reactivity. Circulating noradrenaline adrenaline increased (p<0.05; HPLC). Also, adrenals animals higher content (p<0.05). Then, studied activity. Chronically displayed lower ACTH secretion (ELISA) downregulation POMC expression (qPCR) anterior pituitary addition, induced reduction As expected, corticosterone enhanced an effect was inhibited Finally, PRL gene downregulated more pronounced when also Our results suggest alters neuroendocrine enhancing reactivity reducing activity expression.