*2.2. Chemicals*

The following drugs were used: levo-[ring-2,5,6-3H]-noradrenaline, specific activity 44.8 Ci/mmol (DuPont NEN, I.L.C., Lisboa, Portugal); the scintillation mixture used was from OptiPhase 'Hisafe' 3, PerkinElmer, I.L.C. (Lisboa, Portugal); desipramine hydrochloride purchased from Sigma-Aldrich (Sintra, Portugal). Entellan (mounting medium), Orcein, Masson's trichrome and haematoxylin/eosin from Merck (Darmstadt, Germany). The following antibodies were used: mouse monoclonal anti-tyrosine hydroxylase antibody (ab137869), from Abcam, London, UK) and Alexa Fluor 488 goat anti-mouse IgG (H+L) antibody, highly cross-adsorbed (Invitrogen, Life Technologies, SA, Madrid, Spain); vectashield mounting medium with DAPI (Vector Laboratories, London, UK). Stock solutions were made up in ultrapure water and diluted in superfusion medium immediately before use.

#### *2.3. Haemodynamic Parameters Measurement*

Haemodynamic parameters were determined as previously described [49]. Briefly, the rats were anesthetized (37.5 mg/kg Ketamine hydrochloride and 0.25 mg/kg Medetomidine hydrochloride i.p.). Thereafter, a cannula was inserted into the right iliac artery and connected to a Pressure transducer (Statham, Harvard Apparatus GmbH, Berlin, Germany). The blood pressure wave was recorded on a PC computer, using the data acquisition with the PowerLab system (ADInstruments) for 60 min and systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured in the final portion of the recorded trace.
