Central but not systemic administration of ghrelin induces wakefulness in mice

Éva Szentirmai

doi:10.1371/journal.pone.0041172

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Central but not systemic administration of ghrelin induces wakefulness in mice

Journal article

Open access

Central but not systemic administration of ghrelin induces wakefulness in mice

Éva Szentirmai

PloS one, Vol.7(7), pp.e41172-e41172

2012

DOI: https://doi.org/10.1371/journal.pone.0041172

Handle:

https://hdl.handle.net/2376/103860

PMCID: PMC3398952

PMID: 22815958

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Abstract

Eating

Ghrelin - administration & dosage

Telemetry - methods

Orexins

Mice, Inbred C57BL

Ghrelin - chemistry

Feeding Behavior

Male

Neuropeptides - metabolism

Intracellular Signaling Peptides and Proteins - metabolism

Body Temperature

Electroencephalography - methods

Dose-Response Relationship, Drug

Ghrelin - metabolism

Neuropeptide Y - metabolism

Peptide Hormones - metabolism

Animals

Hypothalamus - metabolism

Sleep

Models, Biological

Wakefulness

Mice

Neurons - metabolism

Infusions, Intraventricular

Ghrelin is a brain-gut peptide hormone widely known for its orexigenic and growth hormone-releasing activities. Findings from our and other laboratories indicate a role of ghrelin in sleep regulation. The effects of exogenous ghrelin on sleep-wake activity in mice are, however, unknown. The aim of the present study was to determine the sleep-modulating effects of ghrelin after central and systemic administrations in mice. Sleep-wake activity after intracerebroventricular (i.c.v.) administration of 0.2, 1 and 5 µg ghrelin and intraperitoneal injections of 40, 100, and 400 µg/kg ghrelin prior to light onset were determined in C57BL/6 mice. In addition, body temperature, motor activity and 1-hour food intake was measured after the systemic injections. Sleep effects of systemic ghrelin (40 and 400 µg/kg) injected before dark onset were also determined. I.c.v. injection of ghrelin increased wakefulness and suppressed non-rapid-eye-movement sleep and electroencephalographic slow-wave activity in the first hour after injections. Rapid-eye-movement sleep was decreased for 2-4 hours after each dose of ghrelin. Sytemic administration of ghrelin did not induce changes in sleep-wake activity in mice at dark or light onset. Motor activity and body temperature remained unaltered and food intake was significantly increased after systemic injections of ghrelin given prior the light period. These findings indicate that the activation of central, but not peripheral, ghrelin-sensitive mechanisms elicits arousal in mice. The results are consistent with the hypothesis that the activation of the hypothalamic neuronal circuit formed by ghrelin, orexin, and neuropeptide Y neurons triggers behavioral sequence characterized by increased wakefulness, motor activity and feeding in nocturnal rodents.

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Title: Central but not systemic administration of ghrelin induces wakefulness in mice
Creators: Éva Szentirmai - Washington, Wyoming, Alaska, Montana and Idaho (WWAMI) Medical Education Program, Washington State University, Spokane, Washington, United States of America. eszentirmai@wsu.edu
Publication Details: PloS one, Vol.7(7), pp.e41172-e41172
Academic Unit: Biomedical Sciences, Department of
Publisher: United States
Identifiers: 99900547090301842
Language: English
Resource Type: Journal article