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

ORILLO, SANTIAGO JORDI; IMSEN, MERCEDES; LIZARRAGA, ALFONSINA; ROMERO, ANA CLARA; DE FINO, FERNANDA; PEÑA, M.; ABELEDO MACHADO, A I; FERRARIS, JIMENA; DÍAZ-TORGA, G; PISERA, DANIEL

Congreso; ENDO 2021; 2021

Stressful stimuli evoke a complex response mediated by twosystems: the Sympathetic-Adreno-Medullar (SAM) axis andthe Hypothalamus-Pituitary-Adrenal (HPA) axis. Among thefactors involved in stress, glucocorticoids and catecholaminessecreted from the adrenal glands and sympathetic nerves arethe main effectors of the physiological adaptations to stressors.Besides these, prolactin (PRL) is another hormone secretedunder stress conditions. Catecholamines are synthesized fromthe hydroxylated precursor L-Dopa. This agent is commonlyused for the treatment of Parkinson?s disease and it wouldact as a neurotransmitter per se. On the other hand, it hasbeen suggested that HPA axis dysregulation is a potentialrisk factor for the development of depression. In line withthis, several studies reported that L-Dopa treatment mayalter the serum levels of ACTH, PRL, and glucocorticoids inparkinsonian patients and Parkinson?s disease animal models.In the present study, we determined whether the chronictreatment with L-Dopa altered the stress response inducingdepressive-like behaviours. Adult male Wistar rats weretreated orally during 24 days with LEBOCAR® - commercialformulation of L-Dopa (75 mg/day) and Carbidopa (7.5 mg/day) - in drinking water. Animals were stressed by immobilization during the last 9 days of treatment and depressivelike behaviours were assessed by the sucrose intake andforced swimming tests. Behavioural tests showed no signs ofdepressive-like behaviours in the LEBOCAR®-treated and/or stressed rats. We next explored the SAM axis reactivity.Circulating noradrenaline and adrenaline increased in ratstreated with LEBOCAR® (p