Katarzyna Jodko-Piórecka

Dopamine – a neurotransmitter with antioxidant activity

Katarzyna Jodko-Piórecka, UW
Supervisor: dr hab. Grzegorz Litwinienko (UW)

Dopamine plays a crucial role in a receptor-related signal transduction in mammalian central and peripheral nervous systems. Moreover, this molecule might behave as endogenous phenolic antioxidant protecting the neuronal tissue from deleterious effects of oxidative stress.
Weak interactions between dopamine and neuronal membranes have been suggested to modulate synaptic transmission and may be crucial for the antioxidant activity of dopamine. However, the strength of these interactions has not been provided so far. Herein, we employed Isothermal Titration Calorimetry and Differential Titration Calorimetry for the detailed characterization of dopamine binding to lipid membranes and its impact on the lipid phase behavior. The calorimetric studies were performed on unilamellar phosphatidylcholine vesicles with varied surface charge. Our calorimetric studies gave a complete thermodynamic picture of dopamine interaction with lipid membranes. A simple model for the binding of dopamine to lipid membranes is proposed, indicating that dopamine-membrane interactions have a dominant electrostatic component, thus, negative membrane charge is crucial for the coulombic attraction of dopamine.
The ability of dopamine to inhibit peroxidation of tested lipid systems was verified in phosphatidylcholine / methyl linoleate mixed unilamellar vesicles with varied surface charge. Obtained results are physiologically relevant since biological membranes contain a large fraction of negatively charged lipids (in synapses even 20% of lipids is anionic) and give a full picture of antioxidant activity of dopamine in relation to its interaction with lipid membranes.

Mrs. Chairwoman - prof. Magdalena Rakowska-Boguta

His Magnificence Rector of Warsaw University of Technology - prof. Jan Szmidt - Guest of the Symposium

Discussion