The neurotransmitter gamma-aminobutiric acid (GABA) regulates Tcell proliferation

DIONISIO L; DE ROSA MJ; BOUZAT C; ESANDI MC

Buenos Aires, Argentina

Congreso; III Iberoamerican Congress on Neuroimmunomodulation; 2009

GABA is an ubiquitous neurotransmitter in the central nervous system. The goal of this study was to determine if components of the GABAergic system are expressed in lymphocytes and whether their presence had any functional significance. Using RT-PCR we analyzed expression of mRNA of different components of this system in resting and activated lymphocytes (PHA 10 mg/ml): i) GAD67, an isoform of the enzyme that synthetizes GABA; ii) VIAAT, the vesicular protein involved in GABA store; iii) GABA transporters (GAT1-2); iv) GABA-T, the enzyme that catabolizes GABA; v) alpha subunits (a1-6) of GABAA receptor; and vi) rho2 subunit of the GABAC receptor. The functionality of the transporters was evaluated by measuring uptake of radioactive GABA. The results demonstrated that the uptake of GABA is significantly higher in activated lymphocytes than in resting ones. Finally, using [3H] thymidine incorporation, we established that GABA is able to modulate lymphocyte proliferation. Our results revealed that lymphocytes have most of the essential components needed to constitute a non-neuronal GABAergic system. Pharmacological modulation of this system may provide new approaches for regulation of T cell response. Furthermore, elucidation of its function will contribute to clarify the interactions between the nervous and immune systems.