A potent non-monoaminergic paradoxical sleep inhibitory system: a reverse microdialysis and single-unit recording study.
Using reverse microdialysis and polygraphic recordings in freely moving cats, we investigated the effects on sleep-waking states of application of excitatory and inhibitory amino acid agonists, cholinergic agonist and monoamines to the periaqueductal grey and adjacent mesopontine tegmentum. Single-unit recordings during behavioural states were further used to determine the neuronal characteristics of these structures. We found that muscimol, a GABAA receptor agonist, induced a significant increase in paradoxical sleep (PS) only when applied to a dorsocaudal central tegmental field (dcFTC) located just beneath the ventrolateral periaqueductal grey. In this structure, both kainic and N-methyl-aspartic acids caused a dose-dependent increase in wakefulness (W) and decrease in both slow-wave sleep (SWS) and PS. Norepinephrine and epinephrine, and to a lesser extent histamine, also increased W and decreased SWS and PS, whereas serotonin, dopamine and carbachol, a cholinergic agonist, had no effect. Two types of neurones were recorded in this structure, those exhibiting a higher rate of tonic discharge during both W and PS compared with during SWS, and those showing a phasic increase in firing rate during both active W and PS. Both types of neurones showed a gradual increase in unit activity during PS. Our study demonstrated for the first time that the ventrolateral periaqueductal grey and dcFTC play different roles in behavioural state control, that the dcFTC neurones are critically involved in the inhibitory mechanisms of PS generation, playing a central part in its maintenance, and that these neurones are under the control of GABAergic, glutamatergic, adrenergic and histaminergic systems.
Crochet
Sylvain
S
Laboratory of Sensory Processing, Brain and Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL-SV-BMI-AAB105, Bât AAB, Station 15, CH-1015 Lausanne, Switzerland. sylvain.crochet@epfl.ch
Onoe
Hirotaka
H
Sakai
Kazuya
K
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D015306:Biogenic Monoamines / Q000494:pharmacology; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology*; D002217:Carbachol / Q000494:pharmacology; D002415:Cats; D018679:Cholinergic Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018755:GABA Agonists / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D009118:Muscimol / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D010487:Periaqueductal Gray / Q000187:drug effects; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology*; D013681:Tegmentum Mesencephali / Q000166:cytology / Q000187:drug effects*; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology
D015306:Biogenic Monoamines; D018679:Cholinergic Agonists; D018690:Excitatory Amino Acid Agonists; D018755:GABA Agonists; D009118:Muscimol; D016202:N-Methylaspartate; D002217:Carbachol; D007608:Kainic Acid