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Neuronal ensembles sufficient for recovery sleep and the sedative actions of α2 adrenergic agonists.

Zhang Z, Ferretti V, Güntan İ, Moro A, Steinberg EA, Ye Z, Zecharia AY, Yu X, Vyssotski AL, Brickley SG, Yustos R, Pillidge ZE, Harding EC, Wisden W, Franks NP - Nat. Neurosci. (2015)

Bottom Line: For the α2 adrenergic receptor agonist dexmedetomidine, we found that sedation and LORR were in fact distinct states, requiring different brain areas: the preoptic hypothalamic area and locus coeruleus (LC), respectively.Instead, we found that dexmedetomidine-induced sedation resembled the deep recovery sleep that follows sleep deprivation.Thus, α2 adrenergic receptor-induced sedation and recovery sleep share hypothalamic circuitry sufficient for producing these behavioral states.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Imperial College London, South Kensington, UK.

ABSTRACT
Do sedatives engage natural sleep pathways? It is usually assumed that anesthetic-induced sedation and loss of righting reflex (LORR) arise by influencing the same circuitry to lesser or greater extents. For the α2 adrenergic receptor agonist dexmedetomidine, we found that sedation and LORR were in fact distinct states, requiring different brain areas: the preoptic hypothalamic area and locus coeruleus (LC), respectively. Selective knockdown of α2A adrenergic receptors from the LC abolished dexmedetomidine-induced LORR, but not sedation. Instead, we found that dexmedetomidine-induced sedation resembled the deep recovery sleep that follows sleep deprivation. We used TetTag pharmacogenetics in mice to functionally mark neurons activated in the preoptic hypothalamus during dexmedetomidine-induced sedation or recovery sleep. The neuronal ensembles could then be selectively reactivated. In both cases, non-rapid eye movement sleep, with the accompanying drop in body temperature, was recapitulated. Thus, α2 adrenergic receptor-induced sedation and recovery sleep share hypothalamic circuitry sufficient for producing these behavioral states.

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Serial re-activation of genetically tagged neuronal ensembles following dexmedetomidine-induced sedation and recovery sleep. (a) Percentage NREM sleep after dexmedetomidine. Both LPO-TetTag-hM3Dq (n=6) and MnPO-TetTag-hM3Dq (n=6) mice showed sustained NREM, significantly greater than control (P<0.0001). Data shown are for LPO-TetTag-hM3Dq mice. (b) Speed in an open field 30 min after dexmedetomidine. Data shown are for LPO-TetTag-hM3Dq mice (n=7). (c) NREM sleep after CNO injection, four days after dexmedetomidine sedation. Filled circles: LPO-TetTag-hM3Dq mice (n=7; P<0.0001, compared to control) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=6; P<0.001, compared to control) mice after CNO injection. Open circles: LPO-TetTag-hM3Dq (n=9) mice after control CNO injection without prior sedation or recovery sleep. (d) Speed in an open field 30 min after CNO injection, four days after dexmedetomidine sedation. Filled circles: after CNO injection for LPO-TetTag-hM3Dq mice. Filled triangles: after CNO injection for MnPO-TetTag-hM3Dq mice. Open circles: after control CNO injection without prior sedation or recovery sleep. CNO recapitulated the effects of dexmedetomidine in LPO-TetTag-hM3Dq (n=8; P<0.0001) but not in MnPO-TetTag-hM3Dq mice (n=6; P=0.1) compared to control (n=7). (e) NREM after 4 hours sleep deprivation (SD) (n=6). (f) Speed in an open field 30 min during recovery sleep (n=8). (g) NREM sleep after CNO injection, four days after sleep deprivation/recovery sleep. Filled circles: LPO-TetTag-hM3Dq mice (n=8; P<0.0001, compared to baseline) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=7; P<0.0001, two-way ANOVA compared to baseline) mice after CNO injection. (h) Speed in open field 30 min after CNO injection, four days after recovery sleep. CNO recapitulated the effects of recovery sleep in both LPO-TetTag-hM3Dq (n=8; P<0.0001) and in MnPO-TetTag-hM3Dq mice (n=7; P<0.0001, two-way ANOVA) compared to baseline (n=7). For all panels the error bars represent s.e.m and the statistical tests were two-way ANOVA.
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Figure 4: Serial re-activation of genetically tagged neuronal ensembles following dexmedetomidine-induced sedation and recovery sleep. (a) Percentage NREM sleep after dexmedetomidine. Both LPO-TetTag-hM3Dq (n=6) and MnPO-TetTag-hM3Dq (n=6) mice showed sustained NREM, significantly greater than control (P<0.0001). Data shown are for LPO-TetTag-hM3Dq mice. (b) Speed in an open field 30 min after dexmedetomidine. Data shown are for LPO-TetTag-hM3Dq mice (n=7). (c) NREM sleep after CNO injection, four days after dexmedetomidine sedation. Filled circles: LPO-TetTag-hM3Dq mice (n=7; P<0.0001, compared to control) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=6; P<0.001, compared to control) mice after CNO injection. Open circles: LPO-TetTag-hM3Dq (n=9) mice after control CNO injection without prior sedation or recovery sleep. (d) Speed in an open field 30 min after CNO injection, four days after dexmedetomidine sedation. Filled circles: after CNO injection for LPO-TetTag-hM3Dq mice. Filled triangles: after CNO injection for MnPO-TetTag-hM3Dq mice. Open circles: after control CNO injection without prior sedation or recovery sleep. CNO recapitulated the effects of dexmedetomidine in LPO-TetTag-hM3Dq (n=8; P<0.0001) but not in MnPO-TetTag-hM3Dq mice (n=6; P=0.1) compared to control (n=7). (e) NREM after 4 hours sleep deprivation (SD) (n=6). (f) Speed in an open field 30 min during recovery sleep (n=8). (g) NREM sleep after CNO injection, four days after sleep deprivation/recovery sleep. Filled circles: LPO-TetTag-hM3Dq mice (n=8; P<0.0001, compared to baseline) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=7; P<0.0001, two-way ANOVA compared to baseline) mice after CNO injection. (h) Speed in open field 30 min after CNO injection, four days after recovery sleep. CNO recapitulated the effects of recovery sleep in both LPO-TetTag-hM3Dq (n=8; P<0.0001) and in MnPO-TetTag-hM3Dq mice (n=7; P<0.0001, two-way ANOVA) compared to baseline (n=7). For all panels the error bars represent s.e.m and the statistical tests were two-way ANOVA.

Mentions: The following sequence of results is illustrated with LPO-TetTag-hM3Dq and MnPO-TetTag-hM3Dq mice first undergoing dexmedetomidine-induced sedation, followed by CNO treatment, then after a one month gap, 4 hours sleep deprivation and recovery sleep followed by CNO treatment (Figs. 4 and 5). Approximately five minutes after dexmedetomidine injection, the EEG of both LPO-TetTag-hM3Dq and MnPO-TetTag-hM3Dq mice exhibited prominent and sustained NREM which lasted ~90 minutes relative to the mice given only saline (Figs. 4a and 5a). All dexmedetomidine-injected mice became immobile (Fig. 4b), but still had a righting reflex. Mice were then put back on the doxycycline diet for 4 days to repress the induction of further TetTag-hM3Dq receptors, and after this injected i.p. with CNO or saline and their EEG and behavioral responses recorded (Figs. 4c,d and 5b). (The mice used in our study exhibited maximal periods of NREM sleep during the “lights on” part of the cycle (Supplementary Fig. 7a,b). All CNO injections were therefore carried out during this period when the mice were most active.)


Neuronal ensembles sufficient for recovery sleep and the sedative actions of α2 adrenergic agonists.

Zhang Z, Ferretti V, Güntan İ, Moro A, Steinberg EA, Ye Z, Zecharia AY, Yu X, Vyssotski AL, Brickley SG, Yustos R, Pillidge ZE, Harding EC, Wisden W, Franks NP - Nat. Neurosci. (2015)

Serial re-activation of genetically tagged neuronal ensembles following dexmedetomidine-induced sedation and recovery sleep. (a) Percentage NREM sleep after dexmedetomidine. Both LPO-TetTag-hM3Dq (n=6) and MnPO-TetTag-hM3Dq (n=6) mice showed sustained NREM, significantly greater than control (P<0.0001). Data shown are for LPO-TetTag-hM3Dq mice. (b) Speed in an open field 30 min after dexmedetomidine. Data shown are for LPO-TetTag-hM3Dq mice (n=7). (c) NREM sleep after CNO injection, four days after dexmedetomidine sedation. Filled circles: LPO-TetTag-hM3Dq mice (n=7; P<0.0001, compared to control) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=6; P<0.001, compared to control) mice after CNO injection. Open circles: LPO-TetTag-hM3Dq (n=9) mice after control CNO injection without prior sedation or recovery sleep. (d) Speed in an open field 30 min after CNO injection, four days after dexmedetomidine sedation. Filled circles: after CNO injection for LPO-TetTag-hM3Dq mice. Filled triangles: after CNO injection for MnPO-TetTag-hM3Dq mice. Open circles: after control CNO injection without prior sedation or recovery sleep. CNO recapitulated the effects of dexmedetomidine in LPO-TetTag-hM3Dq (n=8; P<0.0001) but not in MnPO-TetTag-hM3Dq mice (n=6; P=0.1) compared to control (n=7). (e) NREM after 4 hours sleep deprivation (SD) (n=6). (f) Speed in an open field 30 min during recovery sleep (n=8). (g) NREM sleep after CNO injection, four days after sleep deprivation/recovery sleep. Filled circles: LPO-TetTag-hM3Dq mice (n=8; P<0.0001, compared to baseline) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=7; P<0.0001, two-way ANOVA compared to baseline) mice after CNO injection. (h) Speed in open field 30 min after CNO injection, four days after recovery sleep. CNO recapitulated the effects of recovery sleep in both LPO-TetTag-hM3Dq (n=8; P<0.0001) and in MnPO-TetTag-hM3Dq mice (n=7; P<0.0001, two-way ANOVA) compared to baseline (n=7). For all panels the error bars represent s.e.m and the statistical tests were two-way ANOVA.
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Figure 4: Serial re-activation of genetically tagged neuronal ensembles following dexmedetomidine-induced sedation and recovery sleep. (a) Percentage NREM sleep after dexmedetomidine. Both LPO-TetTag-hM3Dq (n=6) and MnPO-TetTag-hM3Dq (n=6) mice showed sustained NREM, significantly greater than control (P<0.0001). Data shown are for LPO-TetTag-hM3Dq mice. (b) Speed in an open field 30 min after dexmedetomidine. Data shown are for LPO-TetTag-hM3Dq mice (n=7). (c) NREM sleep after CNO injection, four days after dexmedetomidine sedation. Filled circles: LPO-TetTag-hM3Dq mice (n=7; P<0.0001, compared to control) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=6; P<0.001, compared to control) mice after CNO injection. Open circles: LPO-TetTag-hM3Dq (n=9) mice after control CNO injection without prior sedation or recovery sleep. (d) Speed in an open field 30 min after CNO injection, four days after dexmedetomidine sedation. Filled circles: after CNO injection for LPO-TetTag-hM3Dq mice. Filled triangles: after CNO injection for MnPO-TetTag-hM3Dq mice. Open circles: after control CNO injection without prior sedation or recovery sleep. CNO recapitulated the effects of dexmedetomidine in LPO-TetTag-hM3Dq (n=8; P<0.0001) but not in MnPO-TetTag-hM3Dq mice (n=6; P=0.1) compared to control (n=7). (e) NREM after 4 hours sleep deprivation (SD) (n=6). (f) Speed in an open field 30 min during recovery sleep (n=8). (g) NREM sleep after CNO injection, four days after sleep deprivation/recovery sleep. Filled circles: LPO-TetTag-hM3Dq mice (n=8; P<0.0001, compared to baseline) after CNO injection. Filled triangles: MnPO-TetTag-hM3Dq (n=7; P<0.0001, two-way ANOVA compared to baseline) mice after CNO injection. (h) Speed in open field 30 min after CNO injection, four days after recovery sleep. CNO recapitulated the effects of recovery sleep in both LPO-TetTag-hM3Dq (n=8; P<0.0001) and in MnPO-TetTag-hM3Dq mice (n=7; P<0.0001, two-way ANOVA) compared to baseline (n=7). For all panels the error bars represent s.e.m and the statistical tests were two-way ANOVA.
Mentions: The following sequence of results is illustrated with LPO-TetTag-hM3Dq and MnPO-TetTag-hM3Dq mice first undergoing dexmedetomidine-induced sedation, followed by CNO treatment, then after a one month gap, 4 hours sleep deprivation and recovery sleep followed by CNO treatment (Figs. 4 and 5). Approximately five minutes after dexmedetomidine injection, the EEG of both LPO-TetTag-hM3Dq and MnPO-TetTag-hM3Dq mice exhibited prominent and sustained NREM which lasted ~90 minutes relative to the mice given only saline (Figs. 4a and 5a). All dexmedetomidine-injected mice became immobile (Fig. 4b), but still had a righting reflex. Mice were then put back on the doxycycline diet for 4 days to repress the induction of further TetTag-hM3Dq receptors, and after this injected i.p. with CNO or saline and their EEG and behavioral responses recorded (Figs. 4c,d and 5b). (The mice used in our study exhibited maximal periods of NREM sleep during the “lights on” part of the cycle (Supplementary Fig. 7a,b). All CNO injections were therefore carried out during this period when the mice were most active.)

Bottom Line: For the α2 adrenergic receptor agonist dexmedetomidine, we found that sedation and LORR were in fact distinct states, requiring different brain areas: the preoptic hypothalamic area and locus coeruleus (LC), respectively.Instead, we found that dexmedetomidine-induced sedation resembled the deep recovery sleep that follows sleep deprivation.Thus, α2 adrenergic receptor-induced sedation and recovery sleep share hypothalamic circuitry sufficient for producing these behavioral states.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Imperial College London, South Kensington, UK.

ABSTRACT
Do sedatives engage natural sleep pathways? It is usually assumed that anesthetic-induced sedation and loss of righting reflex (LORR) arise by influencing the same circuitry to lesser or greater extents. For the α2 adrenergic receptor agonist dexmedetomidine, we found that sedation and LORR were in fact distinct states, requiring different brain areas: the preoptic hypothalamic area and locus coeruleus (LC), respectively. Selective knockdown of α2A adrenergic receptors from the LC abolished dexmedetomidine-induced LORR, but not sedation. Instead, we found that dexmedetomidine-induced sedation resembled the deep recovery sleep that follows sleep deprivation. We used TetTag pharmacogenetics in mice to functionally mark neurons activated in the preoptic hypothalamus during dexmedetomidine-induced sedation or recovery sleep. The neuronal ensembles could then be selectively reactivated. In both cases, non-rapid eye movement sleep, with the accompanying drop in body temperature, was recapitulated. Thus, α2 adrenergic receptor-induced sedation and recovery sleep share hypothalamic circuitry sufficient for producing these behavioral states.

Show MeSH