Intraventricular melanin-concentrating hormone stimulates water intake independent of food intake.
The lateral hypothalamus (LH) has a critical role in the control of feeding and drinking. Melanin-concentrating hormone (MCH) is an orexigenic peptidergic neurotransmitter produced primarily in the LH, and agouti-related protein (AgRP) is an orexigenic peptidergic neurotransmitter produced exclusively in the arcuate (ARC), an area that innervates the LH. We assessed drinking and eating after third ventricular (i3vt) administration of MCH and AgRP. MCH (2.5, 5, and 10 micro g i3vt) significantly increased food as well as water intake over 4 h when administered during either the light or the dark portion of the day-night cycle. When MCH (5 micro g) was administered to rats with access to water but no food, they drank significantly more water than when given the vehicle. AgRP (7 micro g i3vt), on the other hand, increased water intake but only in proportion to food intake during the dark and the light, and water intake was not increased after i3vt AgRP in the absence of food. Hence, in contrast to AgRP, MCH elicits increased water intake independent of food intake. These results are consistent with historical data linking activity of the LH with water as well as food intake.
Clegg
Deborah J
DJ
Department of Psychiatry, University of Cincinnati, Ohio 45267, USA. debbie.clegg@uc.edu
Air
Ellen L
EL
Benoit
Stephen C
SC
Sakai
Randall S
RS
Seeley
Randy J
RJ
Woods
Stephen C
SC
D054369:Agouti-Related Protein; D000818:Animals; D002940:Circadian Rhythm; D004231:Diuresis / Q000187:drug effects; D004327:Drinking Behavior / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects*; D007028:Hypothalamic Hormones / Q000008:administration & dosage* / Q000494:pharmacology*; D007276:Injections, Intraventricular; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008543:Melanins / Q000008:administration & dosage* / Q000494:pharmacology*; D009994:Osmolar Concentration; D010907:Pituitary Hormones / Q000008:administration & dosage* / Q000494:pharmacology*; D011506:Proteins / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans
C515197:AGRP protein, rat; D054369:Agouti-Related Protein; D007028:Hypothalamic Hormones; D036341:Intercellular Signaling Peptides and Proteins; D008543:Melanins; D010907:Pituitary Hormones; D011506:Proteins; C019463:melanin-concentrating hormone