Cellular mechanisms of thermosensing in orexin neurons

Belanger-Willoughby, Natasha (2013) Cellular mechanisms of thermosensing in orexin neurons. Masters thesis, Memorial University of Newfoundland.

[img] [English] PDF - Accepted Version
Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.

Download (5Mb)

Abstract

Hypothalamic orexin neurons promote energy intake and expenditure. Thus, satiety and behavioural inactivity that accompany post-prandial rises in body temperature may, in part, be explained by the inhibition of orexin neurons. Using whole-cell patch clamp on rat brain slices, I investigated cellular mechanisms of orexin thermosensing. Orexin neurons are inhibited by elevated temperatures in-vitro but neighboring melanin-concentrating hormone neurons are not temperature-sensitive. Orexin neuronal inhibition is mediated by A TP-sensitive potassium channels, which are modulated by the UCP2 inhibitor genipin. Warming additionally revealed an increase in glutamatergic transmission (mEPSCs). This effect was attenuated by the transient receptor potential vanilloid-1 (TRPV 1) channel inhibitor AMG9810, suggesting mediation by pre- and post-synaptic TRPV 1 channels. Orexin neurons in rats overfed with high-fat westerndiet had impaired thermosensing mechanisms. In conclusion, this study suggests that postprandial thermogenesis inhibits orexin neurons to promote satiety and lethargic behaviours and additionally implicates a role for orexin thermosensing in diet-induced overconsumption.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/10148
Item ID: 10148
Additional Information: Includes bibliographical references (leaves 76-106)
Department(s): Medicine, Faculty of
Date: 2013
Date Type: Submission
Library of Congress Subject Heading: Neurons--Physiology; Orexins--Effect of heat on; Thermoreceptors
Medical Subject Heading: Neurons--physiology; Thermoreceptors

Actions (login required)

View Item View Item

Downloads

Downloads per month over the past year

View more statistics