Catecholamines in Macrophages Background |
The discovery
of catecholamines in several types of immune cells has
opened a new area of investigation to determine how these
cells acquire and use catecholamines. Students working with Dr. Jennifer
Stewart in VCU’s Department of Biology contributed
to the evidence that cells of the immune system
synthesize catecholamines: |
Catecholamines include norepinephrine,
epinephrine, and dopamine. These monoamines are synthesized from
the amino acid tyrosine in the brain, adrenal medulla, and the
sympathetic nervous system.
n, Jessica Freeman and undergraduate
Carolene Lewis used in situ hybridization and a
radioenzymatic assay to further characterize the location
and activity of this enzyme in spleen and thymus. These
findings are important because epinephrine is the most
potent naturally occurring molecule that binds to the
beta-2 adrenergic receptor found on many immune cells.
Also, graduate student Jessica Freeman demonstrated that murine bone marrow derived mast cells
synthesize and release large quantities of dopamine. This
study further showed that dopamine promotes programmed
cell death (apoptosis) in mast cells and may function as
an autocrine inhibitor of mast cell proliferation.