1. Neuronal basis of the slow (<1 Hz) oscillation in neurons of the nucleus reticularis thalami in vitro.
- Author
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Blethyn KL, Hughes SW, Tóth TI, Cope DW, and Crunelli V
- Subjects
- Action Potentials drug effects, Action Potentials radiation effects, Animals, Apamin pharmacology, Cadmium pharmacology, Cats, Computer Simulation, Cycloleucine analogs & derivatives, Cycloleucine pharmacology, Dose-Response Relationship, Radiation, Drug Interactions, Electric Capacitance, Electric Stimulation methods, Excitatory Amino Acid Antagonists pharmacology, GABA Antagonists pharmacology, In Vitro Techniques, Models, Neurological, Neural Pathways drug effects, Neural Pathways radiation effects, Neurons drug effects, Neurons radiation effects, Neuroprotective Agents pharmacology, Nickel pharmacology, Organophosphorus Compounds pharmacology, Pyridazines pharmacology, Pyrimidines pharmacology, Sodium Channel Blockers pharmacology, Tetrodotoxin pharmacology, Time Factors, Intralaminar Thalamic Nuclei cytology, Neurons physiology, Periodicity
- Abstract
During deep sleep and anesthesia, the EEG of humans and animals exhibits a distinctive slow (<1 Hz) rhythm. In inhibitory neurons of the nucleus reticularis thalami (NRT), this rhythm is reflected as a slow (<1 Hz) oscillation of the membrane potential comprising stereotypical, recurring "up" and "down" states. Here we show that reducing the leak current through the activation of group I metabotropic glutamate receptors (mGluRs) with either trans-ACPD [(+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid] (50-100 microM) or DHPG [(S)-3,5-dihydroxyphenylglycine] (100 microM) instates an intrinsic slow oscillation in NRT neurons in vitro that is qualitatively equivalent to that observed in vivo. A slow oscillation could also be evoked by synaptically activating mGluRs on NRT neurons via the tetanic stimulation of corticothalamic fibers. Through a combination of experiments and computational modeling we show that the up state of the slow oscillation is predominantly generated by the "window" component of the T-type Ca2+ current, with an additional supportive role for a Ca2+-activated nonselective cation current. The slow oscillation is also fundamentally reliant on an Ih current and is extensively shaped by both Ca2+- and Na+-activated K+ currents. In combination with previous work in thalamocortical neurons, this study suggests that the thalamus plays an important and active role in shaping the slow (<1 Hz) rhythm during deep sleep.
- Published
- 2006
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