Catharanthine is derived from the Catharanthus roseus plant and is an analog to ibogaine, a drug that reduces opioid and alcohol withdrawal symptoms and decreases drug self-administration in both animals and humans. Catharanthine has promise to be an alternative pharmacological treatment for addiction without the adverse side effects associated with ibogaine. The objective of this study was to evaluate catharanthine’s effects on dopamine (DA) transmission in the mesolimbic DA system as well as determine its effects on both ethanol withdrawal induced anxiety and drug-seeking behaviors in mice. We hypothesized that catharanthine would inhibit evoked DA release in the nucleus accumbens (NAc) while also reducing anxiety and drug seeking behaviors in mice. We found that superfusion of catharanthine (1-100 µM) to mouse brain slices significantly inhibits evoked DA release in the NAc of the striatum in a dose dependent manner, while also slowing DA reuptake through inhibition of the dopamine transporter (DAT), measured using fast-scan cyclic voltammetry (FSCV). We also found that intraperitoneal administration of catharanthine in live mice significantly increases extracellular DA, measured via microdialysis with electrochemical detection. Catharanthine inhibition of evoked DA release was significantly reduced by the non-selective nAChR antagonist mecamylamine, the α4 nAChR antagonist dihydro-β-erythroidine hydrobromide (DhβE) and the α6 nAChR antagonist α-conotoxin MII, suggesting that catharanthine inhibits α4 and α6 nAChRs in the NAc. Iontophoresis and in-vivo data indicates that catharanthine slows DA reuptake and increases extracellular DA in the NAc through partial inhibition of DATs. Catharanthine also blocked increases in anxiety-like behavior during ethanol withdrawal in mice in the elevated plus maze. Lastly, preliminary data suggests that catharanthine increases both water and ethanol drinking in a 24-hour two-bottle choice drinking paradigm, which was contrary to our hypothesis.
College and Department
BYU ScholarsArchive Citation
Williams, Benjamin M., "Catharanthine Modulates Mesolimbic Dopamine Transmission: A Potential Treatment for Alcohol Use Disorder" (2022). Theses and Dissertations. 9656.
addiction, catharanthine, 18-methoxycoronaridine, dopamine, alcohol, withdrawal, anxiety, voltammetry, nucleus accumbens, nicotinic acetylcholine receptor, dopamine transporter