Central administration of neuropeptide Y induces wakefulness in rats

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2006-08, Vol.291 (2), p.R473-R480
• Main Authors: Szentirmai, E, Krueger, J. M
• Format: Article
• Language: English
• Subjects: Animals; Dose-Response Relationship, Drug; Eating - drug effects; Electroencephalography - drug effects; Hypothalamus - physiology; Injections, Intraperitoneal; Injections, Intraventricular; Male; Neuropeptide Y - administration & dosage; Rats; Rats, Sprague-Dawley; Sleep Stages - drug effects; Wakefulness - drug effects
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00919.2005

1 Department of Physiology, A. Szent-Györgyi Medical and Pharmaceutical Center, University of Szeged, Szeged, Hungary; and 2 Neuroscience Program, Washington State University, Pullman, Washington Submitted 30 December 2005 ; accepted in final form 9 February 2006 Neuropeptide Y (NPY) is a well-characterized neuromodulator in the central nervous system, primarily implicated in the regulation of feeding. NPY, orexins, and ghrelin form a hypothalamic food intake regulatory circuit. Orexin and ghrelin are also implicated in sleep-wake regulation. In the present experiments, we studied the sleep-modulating effects of central administration of NPY in rats. Rats received intracerebroventricular injection of physiological saline or three different doses of NPY (0.4, 2, and 10 µg in a volume of 4 µl) at light onset. Another group of rats received bilateral microinjection of saline or 2 µg NPY in the lateral hypothalamus in a volume of 0.2 µl. Sleep-wake activity and motor activity were recorded for 23 h. Food intake after the control and treatment injections was also measured on separate days. Intracerebroventricular and lateral hypothalamic administration of NPY suppressed non-rapid-eye-movement sleep and rapid-eye-movement sleep in rats during the first hour after the injection and also induced changes in electroencephalogram delta power spectra. NPY stimulated food intake in the first hour after both routes of administration. Data are consistent with the hypothesis that NPY has a role in the integration of feeding, metabolism, and sleep regulation. food intake; lateral hypothalamus; electroencephalogram; fast-Fourier transformation; slow-wave activity Address for reprint requests and other correspondence: J. M. Krueger, Washington State Univ., College of Veterinary Medicine, Dept. of VCAPP, P.O. Box 646520, Pullman, WA 99164-6520 (e-mail: Krueger{at}vetmed.wsu.edu )