snx-482 and bicuculline-methiodide

Cortical pyramidal neurons alter their responses to input signals depending on behavioral state. We investigated whether changes in somatic inhibition contribute to these alterations. In layer 5 pyramidal neurons of rat visual cortex, repetitive firing from a depolarized membrane potential, which typically occurs during arousal, produced long-lasting depression of somatic inhibition. In contrast, slow membrane oscillations with firing in the depolarized phase, which typically occurs during slow-wave sleep, produced long-lasting potentiation. The depression is mediated by L-type Ca2+ channels and GABA(A) receptor endocytosis, whereas potentiation is mediated by R-type Ca2+ channels and receptor exocytosis. It is likely that the direction of modification is mainly dependent on the ratio of R- and L-type Ca2+ channel activation. Furthermore, somatic inhibition was stronger in slices prepared from rats during slow-wave sleep than arousal. This bidirectional modification of somatic inhibition may alter pyramidal neuron responsiveness in accordance with behavioral state.

Topics: 2-Amino-5-phosphonovalerate; Action Potentials; Animals; Animals, Newborn; Bicuculline; Dendrites; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Electric Stimulation; Excitatory Amino Acid Antagonists; GABA Antagonists; gamma-Aminobutyric Acid; Inhibitory Postsynaptic Potentials; Neural Inhibition; Patch-Clamp Techniques; Pyramidal Cells; Quinoxalines; Rats; Rats, Sprague-Dawley; Spider Venoms; Visual Cortex