Calcium levels are tightly regulated inside the cell

calcium levels are tightly regulated inside the cell These neurons are unusual in that they continuously generate rhythmic electrical activity. Ion channels in Gardens cell membranes that are opened by this innate pacemaking allow a constant flow of calcium ions into the cells. Calcium enters most types of cell only in short bursts.

Because calcium levels are tightly regulated inside the cell, the ions must be forced out again — a process that requires energy. James Surmeier, a neurophysiologist at Northwestern University in Chicago, Illinois, and a co-author of the study, wondered whether this was placing the Parkinson's-affected neurons under extra stress.

To test the idea, Surmeier and his colleagues engineered mice to express a fluorescent protein Gardens that is sensitive to the oxidation state of a cell. They expressed the protein in the mitochondria of dopamine-producing neurons.