Lidocaine and procaine alter rat brain amines.

Lidocaine HCl (100 mg/kg i.p.) or procaine HCl (240 mg/kg i.p.) was injected into rats, which were killed after zero to 12 min. Six brain parts were analyzed for serotonin, norepinephrine, and dopamine. Lidocaine induced depletion of serotonin and of dopamine in some regions and elevation in others; however, it produced elevated levels of norepinephrine. Not all brain regions showed a significant change of amines. Procaine induced elevations of serotonin, norepinephrine, and dopamine; norepinephrine elevation occurred in a few brain parts, whereas serotonin and dopamine levels were elevated in all brain regions.