Ionic mechanism of GABAA biphasic synaptic potentials in gustatory nucleus of the solitary tract.

ABSTRACT

Gamma-aminobutyric acid (GABA) is the principal neurotransmitter of synaptic inhibition in the gustatory nucleus of the solitary tract (rNST). High-frequency activation of GABA neurons in the rNST results in biphasic inhibitory postsynaptic potentials (IPSPs) that are initially hyperpolarizing but then became depolarizing. Our results indicate that high-frequency stimulation evokes redistribution of Cl- and K+ ions that shifts IPSP reversal potential in a more positive direction, which produces a biphasic or depolarizing IPSP.