Semba, Kazue
Permanent URI for this collectionhttps://hdl.handle.net/10222/72220
Kazue Semba
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Email: semba@dal.ca
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Item Open Access Social and environmental contexts modulate sleep deprivation-induced c-Fos activation in rats(Elsevier, 2013-11-01) Deurveilher, Samuel; Ryan, Nathan; Burns, Joan; Semba, KazuePeople often sleep deprive themselves voluntarily for social and lifestyle reasons. Animals also appear to stay awake longer as a result of their natural curiosity to explore novel environments and interact socially with conspecifics. Although multiple arousal systems in the brain are known to act jointly to promote and maintain wakefulness, it remains unclear whether these systems are similarly engaged during voluntary vs. forced wakefulness. Using c-Fos immunohistochemistry, we compared neuronal responses in rats deprived of sleep for 2 h by gentle sensory stimulation, exploration under social isolation, or exploration with social interaction, and rats under undisturbed control conditions. In many arousal, limbic, and autonomic nuclei examined (e.g., anterior cingulate cortex and locus coeruleus), the two sleep deprivation procedures involving exploration were similarly effective, and both were more effective than sleep deprivation with sensory stimulation, in increasing the number of c-Fos immunoreactive neurons. However, some nuclei (e.g., paraventricular hypothalamic nucleus and select amygdala nuclei) were more responsive to exploration with social interaction, while others (e.g., histaminergic tuberomammillary nucleus) responded more strongly to exploration in social isolation. In the rostral basal forebrain, cholinergic and GABAergic neurons responded preferentially to exploration with social interaction, whereas resident neurons in general responded most strongly to exploration without social interaction. These results indicate that voluntary exploration with/without social interaction is more effective than forced sleep deprivation with gentle sensory stimulation for inducing c-Fos in arousal and limbic/autonomic brain regions, and suggest that these nuclei participate in different aspects of arousal during sustained voluntary wakefulness.Item Open Access Behavioural and neuronal activation after microinjections of AMPA and NMDA into the perifornical lateral hypothalamus in rats(Elsevier, 2011-10-31) Li, Frederick W; Deurveilher, Samuel; Semba, KazueThe perifornical lateral hypothalamic area (PeFLH), which houses orexin/hypocretin (OX) neurons, is thought to play an important role in arousal, feeding, and locomotor activity. The present study examined behavioural effects of activating PeFLH neurons with microinjections of ionotropic glutamate receptor agonists. Three separate unilateral microinjections of either 1) AMPA (1 and 2 mM in 0.1 l artificial cerebrospinal fluid, ACSF) and ACSF, or 2) NMDA (1 and 10 mM in 0.1 l ACSF), and ACSF were made into the PeFLH of adult male rats. Following each injection, the rats were placed into an open field for behavioural scoring for 45 min. Rats were perfused after the third injection for immunohistochemistry for c-Fos and OX to assess the level of activation of OX neurons. Behavioural analyses showed that, as compared to ACSF conditions, AMPA injections produced a dose-dependent increase in locomotion and rearing that persisted throughout the 45 min recording period, and an increase in drinking. Injection of NMDA at 10 mM, but not 1 mM, induced a transient increase in locomotion and an increase in feeding. Histological analyses showed that while both agonists increased the number of neurons immunoreactive for c-Fos in the PeFLH, only AMPA increased the number of neurons immunoreactive for both c-Fos and OX. There were positive correlations between the number of c-Fos/OX-immunoreactive neurons and the amounts of locomotion, rearing, and drinking. These results support the role of ionotropic glutamate receptors on OX and other neurons in the PeFLH in the regulation of locomotor and ingestive behaviours.Item Open Access Role of polysialylated neural cell adhesion molecule in rapid eye movement sleep regulation in rats(Federation of European Neuroscience Societies and Blackwell Publishing Ltd (currently Wiley), 2009-12-03) Black, Michelle A; Deurveilher, Samuel; Seki, Tatsunori; Marsh, Daniel R; Rutishauser, Urs; Rafuse, Victor F; Semba, KazueRecent evidence suggests that synaptic plasticity occurs during homeostatic processes including sleep-wake regulation, although underlying mechanisms are not well understood. Polysialylated neural cell adhesion molecule (PSA NCAM) is a transmembrane protein that has been implicated in various forms of plasticity. To investigate whether PSA NCAM is involved in the neuronal plasticity associated with spontaneous sleep-wake regulation and sleep homeostasis, three studies were conducted using rats. First, we showed that PSA NCAM immunoreactivity is present in close proximity to key neurons in several nuclei of the sleep-wake system, including the tuberomammillary hypothalamic nucleus, dorsal raphe nucleus, and locus coeruleus. Second, using Western blot analysis and densitometric image analysis of immunoreactivity, we found that 6 h of sleep deprivation changed neither the levels nor the general location of PSA NCAM in the sleep-wake system. Finally, we injected endoneuraminidase (endo N) intracerebroventricularly to examine the effects of PSA removal on sleep-wake states and EEG slow waves at both baseline and during recovery from 6 h of sleep deprivation. Endo N-treated rats showed a small but significant decrease in baseline rapid eye movement (REM) sleep selectively in the late light phase, and a facilitated REM sleep rebound after sleep deprivation, compared to saline-injected controls. Non-REM sleep and wake were unaffected by endo N. These results suggest that PSA NCAM is not particularly involved in the regulation of wake or non-REM sleep, but plays a role in the diurnal pattern of REM sleep as well as in some aspects of REM sleep homeostasis.