Essay
Time of day differences in the number of cytokine-immunoreactive cells in the rat visual and somatosensory cortices: test for activity dependence of cytokine proteins
2007
Handle:
https://hdl.handle.net/2376/2490
Abstract
Sleep is posited to be dependent upon wake activity that in turn increases activity-dependent sleep regulatory substances, such as nerve growth factor (NGF) and the cytokine, tumor necrosis factor alpha (TNFa or TNF). TNFa plays an important role in neural plasticity and, along with NGF, in the regulation of sleep. Since the natural light-dark cycle stimulates activity in the somatosensory cortex (Sctx) during the dark (the rats use their whiskers more) and in the visual cortex (Vctx) during the light (the rats use their eyes more), then analyses of the immunohistochemistry for NGF and TNF in these cortical regions after activity in the dark vs light will allow testing of the hypothesis that NGF and TNFa are sleep-and activity-dependent. The light-dark cycle impacts the Sctx and Vctx EEG in rats in a state-dependent manner (Yasuda et aI., 2005a). At 1 h before light onset, EEG slow wave activity in the Sctx is greater than in the Vctx; while 1 h before dark onset the EEG slow wave activity in the Vctx is greater. Together with the general activity marker Fos, and the neuronal specific marker NeuN, immunohistochemistry was used to locate TNF-IR, NGF-IR, Fos-IR, and NeuN-IR cells in sections of the somatosensory and visual cortices taken from animals 1 hour before light onset and 1 hour before dark onset. In layers II-VI of the Sctx, the number of TNFIR cells increased dramatically in the dark (l-h before light onset) when compared to the light (I-h before dark onset). Also in the Sctx, the NGF-IR cells increased in layers II-III, but only to a p< 0.07. In layers II-IV of the Vctx, the number of NGF-IR cells increased in the light when compared to the dark. The number of Fos-IR cells increased in the dark when compared to the light in both the somatosensory and visual cortices in all layers. The number of NeuN-IR cells increased in the dark when compared to the light in layers V-VI of the Sctx, and also increased in the light when compared to the dark in layer IV in the Vctx. Collectively, these data in part support our hypothesis that sleep is dependent upon the release of sleep regulatory substances that build up during wake activity; however, each sleep regulatory substance and activity marker has a unique pattern in the somatosensory and visual cortices. \n11
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Details
- Title
- Time of day differences in the number of cytokine-immunoreactive cells in the rat visual and somatosensory cortices: test for activity dependence of cytokine proteins
- Creators
- Kirsta Ingalsbe (Author)Lynn Churchill (Author)Alok De (Author)James Krueger (Author)
- Contributors
- Lynn Churchill (Advisor)
- Academic Unit
- Honors Theses (WSU Pullman, Passed with Distinction)
- Identifiers
- 99900590747801842
- Copyright
- http://rightsstatements.org/vocab/InC/1.0/; http://www.ndltd.org/standards/metadata; http://purl.org/eprint/accessRights/OpenAccess; In copyright; Publicly accessible; openAccess
- Language
- English
- Resource Type
- Essay