Highlights Extracellular levels of norepinephrine display dynamic changes during NREM and REM sleep  Phasic activity of locus coeruleus neurons during NREM underlies slow norepinephrine oscillations  Spindles occur at norepinephrine troughs and are abolished by norepinephrine increases  Increased spindles prior to REM reflect the beginning of a long-lasting norepinephrine decline  REM episodes are characterized by a sub-threshold continuous norepinephrine decline  The responsiveness of astrocytic Ca 2+ to norepinephrine is reduced during sleep

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Thirty-five women whose breast cancer had been treated by radiation and 111 in whom it had not underwent unilateral breast reconstruction with the tissue expansion technique after modified radical mastectomy. Their records were reviewed and in a questionnaire the patients reported their own opinion on the results. The two groups differed significantly, because those patients who had been irradiated had a more painful course of expansion and a less over-expansion. Their reconstructed breasts were harder, had more deformities, and they required significantly more capsulotomies. The irradiated group also reported less satisfaction with the cosmetic results and more unfulfilled expectations. Tissue expansion cannot therefore be recommended as a routine procedure for breast reconstruction in patients after irradiation. However, our results do not show whether other methods are better for these patients.

SummaryWe normally regard sleep and wake as two distinct opposing brain states, where sleep requires silence of wake-promoting structures such as the locus coeruleus (LC)-norepinephrine (NE) system. We set out to investigate how cortical NE dynamics and NE-related astrocytic activity relates to LC population activity during sleep states.We show that LC displays regular phasic activity bouts during NREM sleep leading to a slow oscillatory pattern of prefrontal NE levels of which the majority of NE increases does not lead to awakening. NE troughs link to sleep spindles and continued NE decline transitions into REM sleep. Last, we show that prefrontal astrocytes have reduced sensitivity towards NE during sleep.Our results suggest that dynamic changes in the activity of wake-promoting systems during sleep create alternation between crucial sleep processes and broadening of sensitivity towards incoming sensory input.HighlightsExtracellular levels of norepinephrine display dynamic changes during NREM and REM sleepPhasic activity of locus coeruleus neurons during NREM underlies slow norepinephrine oscillationsSpindles occur at norepinephrine troughs and are abolished by norepinephrine increasesIncreased spindles prior to REM reflect the beginning of a long-lasting norepinephrine declineREM episodes are characterized by a sub-threshold continuous norepinephrine declineThe responsiveness of astrocytic Ca2+ to norepinephrine is reduced during sleep

Information transfer within neuronal circuits depends on the balance and recurrent activity of excitatory and inhibitory neurotransmission. Chloride (Cl−) is the major central nervous system (CNS) anion mediating inhibitory neurotransmission. Astrocytes are key homoeostatic glial cells populating the CNS, although the role of these cells in regulating excitatory-inhibitory balance remains unexplored. Here we show that astrocytes act as a dynamic Cl− reservoir regulating Cl− homoeostasis in the CNS. We found that intracellular chloride concentration ([Cl−]i) in astrocytes is high and stable during sleep. In awake mice astrocytic [Cl−]i is lower and exhibits large fluctuation in response to both sensory input and motor activity. Optogenetic manipulation of astrocytic [Cl−]i directly modulates neuronal activity during locomotion or whisker stimulation. Astrocytes thus serve as a dynamic source of extracellular Cl− available for GABAergic transmission in awake mice, which represents a mechanism for modulation of the inhibitory tone during sustained neuronal activity.

MethodsAlanine scan of insulin receptor (IR)-B exon 11 and site-directed mutagenesis of amino acid 718 in human IR-A and IR-B were performed. Ligand affinities to wild type and mutated receptors were studied by displacement of radioactive insulin in binding assay on secreted soluble midi receptors or solubilized semi-purified full length receptors stably expressed in Baby Hamster Kidney cells. Phosphorylation of IR in response to insulin, IGF1 and IGF2 was measured using ELISA.ResultsInsulin, insulin detemir and insulin glargine maximally showed two fold differences in affinity for human IR-A and IR-B, but IGF1 and IGF2 had up to 10 fold preference for IR-A. Alanine scan of exon 11 revealed that position 718 is important for low IGF1 affinity to IR-B. Mutational analysis of amino acid residue 718 in IR-A and IR-B demonstrated that charge is important for IGF1 and IGF2 affinity but not important for insulin affinity. The affinity of IGF1 and IGF2 for the mutant IR-A P718K was comparable to the wild type IR-B whereas the affinity of IGF1 and IGF2 for the mutant IR-B K718P was comparable to the wild type IR-A. Changes in affinity were also reflected in the IR activation pattern.ConclusionMutating position 718 in human IR-B to the proline found at position 718 in human IR-A increased IGF1 and IGF2 affinity to a level comparable to IR-A and mutating position 718 in IR-A to the lysine found at position 718 in IR-B decreased IGF1 and IGF2 affinity to a level comparable to IR-B, whereas a negatively charged glutamate did not. These changes in the affinities were also reflected in the IR phosphorylation pattern, meaning that position 718 is important for both affinity and activation of the receptor. It should be emphasized that none of the mutations affected insulin affinity, indicating that the mutations did not alter the overall receptor structure and that the effect is ligand specific.