GABA(A) receptors mediate inhibition of T cell responses

We describe the presence of functional GABA(A) receptors on T cells. GABA i nhibited anti-CDS and antigen-specific T cell proliferation in vitro in a d ose-dependent manner that was 1) mimicked by the GABA(A), receptor agonist muscimol (but not the GABA(B) receptor agonist baclofen), 2) blocked by GAB A(A) receptor antagonists and a GABA, receptor Cl- channel blocker (picroto xin) and 3) enhanced by pentobarbital. These data suggest that GABA(A) rece ptors mediate this immune inhibition and that these receptors can be modula ted in a similar fashion to their neuronal counterparts. Finally, GABA inhi bited DTH responses in vivo. Thus, pharmacological modulation of GABA(A) re ceptors may provide new approaches to modulate T cell responses in inflamma tion and autoimmune disease. (C) 1999 Elsevier Science B.V. All nights rese rved.