Prostaglandin D2 modulates sleep-related and noradrenaline-induced activity of preoptic and basal forebrain neurons in the rat.
Prostaglandin D2 (PGD2) was applied by pressure through a multibarrel micropipette to sleep-related neurons in the preoptic and neighboring basal forebrain area in head-restrained unanesthetized rats. During wakefulness, PGD2 excited six of 13 sleep-active neurons, inhibited seven of 13 waking-active neurons, and did not affect the remaining neurons. During slow-wave sleep (SWS), however, PGD2 excited only three of 17 sleep-active neurons and inhibited two of 13 waking-active neurons. State-indifferent neurons, which lacked activity related to the sleep-waking state, were insensitive to PGD2 irrespective of wakefulness (n = 24) and SWS (n = 40). These results suggest that PGD2 promotes sleep by exciting sleep-active neurons and by inhibiting waking-active neurons. Furthermore, continuous administration of PGD2 attenuated activity changes associated with wakefulness of five sleep-active and three waking-active neurons tested. Because we had suggested the involvement of preoptic noradrenaline (NA) in arousal, we examined possible modulatory effects of PGD2 on NA-induced neuron responses. PGD2 attenuated NA-induced inhibitory responses in four of six sleep-active neurons and in one of 10 state-indifferent neurons. PGD2 also attenuated NA-induced excitation in four waking-active neurons tested. Accordingly, the modulatory action of PGD2 on sleep-related neurons is important in the mechanism of sleep.
Osaka Bioscience Institute, Suita, Japan.
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Osaka
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Hayaishi
D000818:Animals; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology*; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology*; D016548:Prosencephalon / Q000187:drug effects / Q000502:physiology*; D015230:Prostaglandin D2 / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000187:drug effects* / Q000502:physiology; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology
D015230:Prostaglandin D2; D009638:Norepinephrine