Lidocaine and procaine alter rat brain amines

Area of Science:

• Neuroscience
• Pharmacology
• Biochemistry

Background:

• Lidocaine and procaine are local anesthetics with known effects on neuronal excitability.
• Their precise impact on central neurotransmitter systems, particularly serotonin, norepinephrine, and dopamine, requires further elucidation.

Purpose of the Study:

• To investigate the effects of lidocaine hydrochloride and procaine hydrochloride on the levels of key monoamine neurotransmitters in specific rat brain regions.
• To determine the regional specificity and dose-dependency of these neurochemical alterations.

Main Methods:

• Adult rats received intraperitoneal injections of lidocaine HCl (100 mg/kg) or procaine HCl (240 mg/kg).
• Brain tissues from six distinct regions were collected at intervals from 0 to 12 minutes post-injection.
• Concentrations of serotonin, norepinephrine, and dopamine were quantified using biochemical assays.

Main Results:

• Lidocaine HCl induced region-specific alterations, including depletion and elevation of serotonin and dopamine, and a consistent increase in norepinephrine levels.
• Procaine HCl resulted in widespread elevations of serotonin and dopamine across all analyzed brain regions, with a more limited increase in norepinephrine.
• The observed neurochemical changes varied significantly across different brain regions and were time-dependent within the 12-minute observation window.

Conclusions:

• Both lidocaine and procaine significantly impact central monoamine neurotransmitter systems in the rat brain.
• The differential effects suggest distinct mechanisms of action or regional vulnerabilities to these anesthetic agents.
• These findings contribute to understanding the neurochemical consequences of local anesthetic administration in the central nervous system.