Dopamine Disorganizes the Rhythm of Protein Synthesis Disrupting Self-Organization of Hepatocytes In Vitro

We studied dense 24-hour cultures of rat hepatocytes in serum-free medium on collagencoated slides. As before, a circahoralian rhythm of protein synthesis was observed in control cultures in a fresh medium. No rhythm was found after addition of 1-10 mu M dopamine to the medium containing such cultures. The rhythm was observed after addition of 0.3 mu M ganglioside to pretreated-dopamine cultures. Dopamine is likely to influence the conditioning of intercellular medium with gangliosides. Deficit of this endogenous synchronizing factor in the intercellular medium blocks self-organization of the protein synthesis rhythm. Thus, in contrast to previously studied norepinephrine and serotonin, as well as gangliosides, which organized the population rhythm of protein synthesis, dopamine disorganized the rhythm, impairing direct intercellular interactions.