L norepinephrine hydrochloride

L-norepinephrine hydrochloride, (±)−dopamine hydrochloride, serotonin hydrochloride, epinephrine hydrochloride, tryptamine, (±)−octopamine hydrochloride, (±)−synephrine, tyramine hydrochloride, β-phenethylamine, D,L-metanephrine hydrochloride, adenine riboside, 4-aminobutyric acid, L-tyrosine, L-tryptophan, L-tryptophan-d5 (TRP-D5) and 4-aminobutyric acid-2,2,3,3,4,4-d6 (GABA-D6) were purchased from Sigma-Aldrich Corporation (Milan, Italy). The deuterated internal standards, (±)−norepinephrine-2,5,6,α,β,β-d₆ HCl (NE-D6), 2-(3,4-dihydroxyphenyl)ethyl-1,1,2,2-d₄-amine (DA-D4), serotonin-α,α,β,β-d₄ creatinine sulfate complex (5HT-D4), (±)−epinephrine-2,5,6,α,β,β-d₆ (E-D6), tryptamine-α,α,β,β-d₄ HCl (TRY-D4), (±)−p-octopamine-α,β,β-d₃ HCl (OCT-D3), 2-(4-hydroxyphenyl)ethyl-1,1,2,2-d₄-amine HCl (TYRA-D4), and 2-phenyl-d₅-ethylamine (β-PEA-D5) were obtained from CDN Isotopes (Pointe-Claire, Quebec, Canada). The L-tyrosine-ring-d4 (TYRO-D4) was from Cambridge Isotope Laboratories, Inc. (Tewksbury, MA, USA). The purity of all analytes and labeled internal standards was ≥98%.
Water was purified with a Milli-Q Elix purification system (Millipore, Bedford, MA, USA). High-purity MS-grade solvents (formic acid, methanol, and acetonitrile) were obtained from Fluka (Milan, Italy) and used without further purification.

All experimental groups were compared to a vehicle micro-infused control group. For the first experiment, intra insular propranolol (S(-)-Propranolol hydrochloride, Santa Cruz Biotechnology Inc., Dallas, TX, USA) was administered into the insular cortex at 1, 5 and 10 μg/0.5 μl dissolved in sterile saline. In the second experiment, an intra-insular microinfusion of 1 μg/0, 5 μl of NE (L-Norepinephrine hydrochloride, Sigma-aldrich, St. Louis, MO, USA) was performed. For the third experiment, systemic (oral) propranolol (Laboratorio Chile, subsidiary of TEVA, Chile) was administered dissolved in tap water for 1 h before taste presentation at a dose of 13.3 mg/kg, combined with an intra-insular microinfusion of NE at a dose of 1 μg/0.5 μl, 10 min prior to the neophobia test. For the fourth experiment, systemic epinephrine ((±) Epinephrine hydrochloride, Santa Cruz Biotechnology Inc., Dallas, TX, USA) was dissolved in sterile saline and administered i.p. 30 min before taste presentation using doses of 0.001, 0.01, 0.1 and 1 mg/kg. In the last experiment, systemic epinephrine (0.1 mg/kg) was followed by intra-insular microinjection of propranolol (1, 5 and 10 μg/0.5 μl).