Nitric oxide modulation of tonic and phasic responses mediated by GABA-A receptors in CA1 hippocampal pyramidal neurons.

JAVIER GASULLA; DANIEL J. CALVO

Huerta Grande, Córdoba.

Congreso; XXVIII Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2013

Sociedad Argentina de Investigación en Neurociencias

Nitric Oxide (NO) is a gas messenger that can modulate the activity of neurotransmitter receptors. NO is produced by the nitric oxide synthase (NOS) in hippocampal pyramidal neurons at the postsynaptic active zones of both GABAergic and glutamatergic synapses (1). NO was shown to modulate GABaergic synaptic transmission during early development (1) and to increase frequency of spontaneous IPSC in cultured hippocampal cells (2). In the present study, we examined if endogenously produced, or exogenously applied, NO can modulate tonic (bicuculline-sensitive holding currents) and phasic responses (puff-evoked) mediated by GABA-A receptors in CA1 cells of acute hippocampal slices. L-NAME, a NOS inhibitor which blocks endogenous NO synthesis, produced a significant potentiation of both tonic and phasic current responses evoked by GABA. These results indicate that endogenous NO levels can modulate the activity of GABA-A receptors in the mouse hippocampus. 1. E. Szabadits et al., NMDA receptors in hippocampal GABAergic synapses and their role in nitric oxide signaling, J Neurosci 31, 5893?5904 (2011). 2. S. Zanelli, M. Naylor, J. Kapur, Nitric oxide alters GABAergic synaptic transmission in cultured hippocampal neurons, Brain Res 1297, 23?31 (2009).