Galanin-like peptide (GALP) facilitates thermogenesis via synthesis of prostaglandin E2 by astrocytes in the periventricular zone of the third ventricle.
Administration of galanin-like peptide (GALP) leads to a decrease in both total food intake and body weight 24 h after injection, compared to controls. Moreover, GALP induces an increase in core body temperature. To elucidate the mechanism by which GALP exerts its effect on energy homeostasis, urethane-anesthetized rats were intracerebroventricularly injected with GALP or saline, after which oxygen consumption, heart rate, and body temperature were monitored for 4 h. In some cases, animals were also pretreated with the cyclooxygenase (COX) inhibitor, diclofenac, via intracerebroventricular (i.c.v.) or intravenous (i.v.) injection. c-Fos expression in the brain was also examined after injection of GALP, and the levels of COX and prostaglandin E(2) synthetase (PGES) mRNA in primary cultured astrocytes treated with GALP were analyzed by using qPCR. The i.c.v. injection of GALP caused biphasic thermogenesis, an effect which could be blocked by pretreatment with centrally (i.c.v.), but not peripherally (i.v.) administered diclofenac. c-Fos immunoreactivity was observed in astrocytes in the periventricular zone of the third ventricle. GALP treatment also increased COX-2 and cytosolic PGES, but not COX-1, microsomal PGES-1, or microsomal PGES-2 mRNA levels in cultured astrocytes. We, therefore, suggest that GALP elicits thermogenesis via a prostaglandin E(2)-mediated pathway in astrocytes of the central nervous system.
Faculty of Health Care, Kiryu University, Midori City, Gunma, 379-2392, Japan.
Haruaki
H
Kageyama
Kei
K
Endo
Toshimasa
T
Osaka
Jun
J
Watanabe
Li Hua
LH
Wang
Kazuo
K
Ito
Mamiko
M
Suzuki
Junichi
J
Sakagami
Fumiko
F
Takenoya
Seiji
S
Shioda
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001831:Body Temperature; D002478:Cells, Cultured; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2; D003600:Cytosol / Q000378:metabolism; D004008:Diclofenac / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis*; D044089:Galanin-Like Peptide / Q000494:pharmacology*; D006339:Heart Rate; D006706:Homeostasis; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D010101:Oxygen Consumption; D000071876:Prostaglandin-E Synthases; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D022722:Thermogenesis / Q000187:drug effects*; D020542:Third Ventricle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014158:Transcription, Genetic
D044089:Galanin-Like Peptide; D008565:Membrane Proteins; D016760:Proto-Oncogene Proteins c-fos; D004008:Diclofenac; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496513:Ptgs1 protein, rat; C489691:Ptgs2 protein, rat; D019746:Intramolecular Oxidoreductases; D000071876:Prostaglandin-E Synthases; D015232:Dinoprostone