Anorexigenic and electrophysiological actions of novel ghrelin receptor (GHS-R1A) antagonists in rats.
Here we provide the first pharmacological exploration of the impact of acute central nervous system exposure to three recently developed ghrelin receptor (GHS-R1A) ligands on food intake and on the electrical activity of the target cells for ghrelin in the hypothalamus. Central (i.c.v) injection of GHS-R1A antagonists to rats suppressed food intake induced by i.c.v ghrelin injection (1 microg) in a dose-dependent manner with a total blockade at concentrations of 0.4 microg and 8 microg for JMV 3002 and JMV 2959 respectively. JMV 2810, a partial agonist, also suppressed ghrelin-induced food intake (range: 0.02-2 microg). Moreover all three compounds reduced fasting-induced food intake in rats (i.e. the amount of food eaten during the first hour of food exposure after a 16 h fast). At the single cell level we also explored the effects of the compounds to suppress ghrelin (0.5 microM)-induced changes in electrical activity of arcuate nucleus cells recorded extracellularly in a slice preparation. Preincubation followed by perfusion with the GHS-R1A ligands suppressed the responsiveness of arcuate cells to ghrelin. Thus, the recently developed GHS-R1A ligands (JMV 3002, 2959 and 2810) suppress ghrelin-induced and fasting-induced food intake at the level of the central nervous system. This appears to be mediated, at least in part, by a modulation of the activity of ghrelin-responsive arcuate nucleus cells. As the central ghrelin signalling system has emerged as an important pro-obesity target, it will be important to establish the efficacy of these GHS-R1A ligands to reduce fat mass in clinical studies.
Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
Nicolas
N
Salomé
David
D
Haage
Daniel
D
Perrissoud
Aline
A
Moulin
Luc
L
Demange
Emil
E
Egecioglu
Jean-Alain
JA
Fehrentz
Jean
J
Martinez
Suzanne L
SL
Dickson
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects*; D055724:Electrophysiological Phenomena; D004734:Energy Metabolism; D005215:Fasting; D054439:Ghrelin / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D008024:Ligands; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D054440:Receptors, Ghrelin / Q000037:antagonists & inhibitors*; D013696:Temperature; D013997:Time Factors
D054439:Ghrelin; D008024:Ligands; D054440:Receptors, Ghrelin