GABA A receptors mediate inhibition of T cell responses

We describe the presence of functional GABA A receptors on T cells. GABA inhibited anti-CD3 and antigen-specific T cell proliferation in vitro in a dose-dependent manner that was 1) mimicked by the GABA A receptor agonist muscimol (but not the GABA B receptor agonist baclofen), 2) blocked by GABA A receptor antagonists and a GABA A receptor Cl − channel blocker (picrotoxin) and 3) enhanced by pentobarbital. These data suggest that GABA A receptors mediate this immune inhibition and that these receptors can be modulated in a similar fashion to their neuronal counterparts. Finally, GABA inhibited DTH responses in vivo. Thus, pharmacological modulation of GABA A receptors may provide new approaches to modulate T cell responses in inflammation and autoimmune disease.