RT Journal Article
SR Electronic
T1 Endogenous Glucagon-Like Peptide-1 Reduces Drinking Behavior and Is Differentially Engaged by Water and Food Intakes in Rats
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 16417
OP 16423
DO 10.1523/JNEUROSCI.3267-14.2014
VO 34
IS 49
A1 Naomi J. McKay
A1 Daniela L. Galante
A1 Derek Daniels
YR 2014
UL http://www.jneurosci.org/content/34/49/16417.abstract
AB Glucagon-like peptide-1 (GLP-1) is produced in the ileum and the nucleus of the solitary tract. It is well known that GLP-1 controls food intake, but there is a growing literature indicating that GLP-1 also is involved in fluid intake. It is not known, however, if the observed effects are pharmacological or if endogenous GLP-1 and its receptor contribute to physiological fluid intake control. Accordingly, we blocked endogenous GLP-1 by application of a receptor antagonist and measured subsequent drinking. Furthermore, we measured changes in GLP-1-associated gene expression after water intake, and compared the effects of fluid intake to those caused by food intake. Rats injected with the antagonist exendin-9 (Ex-9) drank more fluid in response to either subcutaneous hypertonic saline or water deprivation with partial rehydration than did vehicle-treated rats. Analysis of licking behavior showed that Ex-9 increased fluid intake by increasing the number of licking bursts, without having an effect on the number of licks per burst, suggesting that endogenous GLP-1 suppresses fluid intake by influencing satiety. Subsequent experiments showed that water intake had a selective effect on central GLP-1-related gene expression, unlike food intake, which affected both central and peripheral GLP-1. Although water and food intakes both affected central GLP-1-relevant gene expression, there were notable differences in the timing of the effect. These results show a novel role of the endogenous GLP-1 system in fluid intake, and indicate that elements of the GLP-1 system can be engaged separately by different forms of ingestive behavior.