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Obestatin alters sleep in rats
Eva Szentirmai1, James M Krueger
1Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Neuroscience Program, Washington State University, College of Veterinary Medicine, Pullman, 99164-6520, USA.
Neuroscience Letters
|June 30, 2006
Summary
Obestatin, a peptide from the ghrelin gene, promotes sleep when centrally administered in rats. This effect, observed after intracerebroventricular injection, suggests a role in satiety and contrasts with ghrelin
Area of Science:
- Neuroscience
- Endocrinology
- Sleep Research
Background:
- Obestatin is a peptide hormone derived from the ghrelin gene.
- Ghrelin is known to stimulate food intake and induce wakefulness in rats.
- The contrasting physiological effects of obestatin and ghrelin suggest distinct roles in appetite and arousal regulation.
Purpose of the Study:
- To investigate the effects of obestatin on sleep-wake activity in rats.
- To determine if central administration of obestatin influences non-rapid-eye-movement sleep (NREMS) and rapid-eye-movement sleep (REMS).
- To compare the sleep-modulating effects of obestatin with those of ghrelin.
Main Methods:
- Rats received intracerebroventricular (i.c.v.) injections of obestatin (1, 4, or 16 microg) or saline at dark onset.
- Sleep-wake activity was monitored for 23 hours post-injection.
- Electroencephalographic (EEG) slow-wave activity was analyzed.
Main Results:
- Intracerebroventricular administration of 16 microg obestatin significantly increased NREMS by approximately 58% in the first hour.
- Obestatin treatment shortened sleep latency and increased the number of NREMS episodes.
- Central obestatin reduced EEG slow-wave activity and led to decreased NREMS and REMS in the second hour; peripheral injections had no significant effect.
Conclusions:
- Centrally administered obestatin exhibits sleep-promoting properties in rats.
- The sleep-inducing effect of obestatin may be linked to its role in behavioral satiety.
- Obestatin and ghrelin, derived from the same gene, exert opposing effects on sleep and appetite regulation.