State-dependent bidirectional modification of somatic inhibition in neocortical pyramidal cells.
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.
Kurotani
Tohru
T
Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan. kurotani@brain.riken.jp
Yamada
Kazumasa
K
Yoshimura
Yumiko
Y
Crair
Michael C
MC
Komatsu
Yukio
Y
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000031:analogs & derivatives / Q000494:pharmacology; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009433:Neural Inhibition / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D017966:Pyramidal Cells / Q000166:cytology*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013111:Spider Venoms / Q000494:pharmacology; D014793:Visual Cortex / Q000166:cytology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D011810:Quinoxalines; C115521:SNX 482; D013111:Spider Venoms; C017069:bicuculline methiodide; D005680:gamma-Aminobutyric Acid; C056723:FG 9041; D015763:2-Amino-5-phosphonovalerate; D001640:Bicuculline