Whole-cell recordings of spontaneous synaptic currents in medial preoptic neurons from rat hypothalamic slices: mediation by amino acid neurotransmitters

Whole-cell recordings in hypothalamic slices from immature rats were used to test the hypothesis that inhibitory and excitatory amino acid neurotransmitters mediate fast synaptic currents in the medial preoptic area (MPOA). Bicuculline methiodide reversibly blocked spontaneous inhibitory postsynaptic currents (IPSCs), and 6-cyano-2,3-dihydroxy-7-nitroquinoxaline (CNOX) blocked spontaneous excitatory postsynaptic currents (EPSCs). These competitive antagonists act at γ-aminobutyric acid (GABA)_A and (NMDA) glutamate receptors, respectively, thus supporting the hypothesis that these amino acid receptors activate most if not all fast synaptic currents in the MPOA.