Elevated levels of gamma amino butyric acid (GABA) in the thymus gland during the immune response.

Innervation of the mammalian thymus gland by both cholinergic and catecholaminergic neuronal projections has been documented. The present results reveal that the inhibitory neurotransmitter, gamma amino butyric acid is also present in the mouse thymus and that it is significantly elevated following challenge with a T-cell dependent antigen. A possible immunomodulatory role for the neurotransmitter is discussed.