Regulation of Circadian Rhythms by Sleep -Wake Centers in the Brainstem and Basal Forebrain

Circadian rhythms are the near-24 hr oscillations in phenomenon including hormone release and the sleep-wake cycle, and in mammals are regulated by the suprachiasmatic nucleus (SCN). The proper interaction of the circadian and sleep-wake cycles is essential for well-being, but the means by which these processes interact is unknown. The nucleus basalis magnocellularis (NBM) in the basal forebrain, as well as the laterodorsal tegmental and pedunculopontine tegmental nuclei in the brainstem are known to play a role in regulating the sleep-wake cycle, and contain projections to the SCN. In this set of studies, C57BL/6J mice were surgically implanted with a stimulating electrode aimed at the PPTg, LDTg or NBM, and a microdialysis cannula aimed at the SCN. Stimulation of the LDTg or PPTg significantly increased acetylcholine (ACh) levels at the SCN. Circadian behavior measurements demonstrated that stimulation of the LDTg, PPTg or NBM during the early night significantly delayed circadian rhythms, while LDTg stimulation during the late night significantly advanced circadian rhythms. Varying the stimulation parameters used with the PPTg induced a change in either ACh, glutamate or both neurotransmitters at the SCN, and only stimulation parameters that affected glutamate levels at the SCN delayed circadian rhythms. Chemical activation of the PPTg during the early night also induced significant delays in circadian rhythms, This data provides evidence for a potential means by which the sleep-wake and circadian cycles may interact, through activation of the PPTg, LDTg or NBM.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Molecular and Integrative Physiology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Abbott, Sabra Margaret

Contributors dc:contributor

• Gillette, Martha U.

• Biology, Neuroscience

Language dc:language

eng

Identifier

(MiAaPQ)AAI3182210

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/87233