RT Journal Article
SR Electronic
T1 Intrapreoptic Microinjection of GHRH or Its Antagonist Alters Sleep in Rats
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2187
OP 2194
DO 10.1523/JNEUROSCI.19-06-02187.1999
VO 19
IS 6
A1 Jianyi Zhang
A1 Ferenc Obál, Jr
A1 Tong Zheng
A1 Jidong Fang
A1 Ping Taishi
A1 James M. Krueger
YR 1999
UL http://www.jneurosci.org/content/19/6/2187.abstract
AB Previous reports indicate that growth hormone–releasing hormone (GHRH) is involved in sleep regulation. The site of action mediating the nonrapid eye movement sleep (NREMS)–promoting effects of GHRH is not known, but it is independent from the pituitary. GHRH (0.001, 0.01, and 0.1 nmol/kg) or a competitive antagonist of GHRH (0.003, 0.3, and 14 nmol/kg) was microinjected into the preoptic area, and the sleep–wake activity was recorded for 23 hr after injection in rats. GHRH elicited dose-dependent increases in the duration and in the intensity of NREMS compared with that in control records after intrapreoptic injection of physiological saline. The antagonist decreased the duration and intensity of NREMS and prolonged sleep latency. Consistent alterations in rapid eye movement sleep (REMS) and in brain temperature were not found. The GHRH antagonist also attenuated the enhancements in NREMS elicited by 3 hr of sleep deprivation. Histological verification of the injection sites showed that the majority of the effective injections were in the preoptic area and the diagonal band of Broca. The results indicate that the preoptic area mediates the sleep-promoting activity of GHRH.