title: Serotonin 1A, 1B, and 7 receptors of the rat medial nucleus accumbens differentially regulate feeding, water intake, and locomotor activity.
abstract: Serotonin (5-HT) signaling has been widely implicated in the regulation of feeding behaviors in both humans and animal models. Recently, we reported that co-stimulation of 5-HT1&7 receptors of the anterior medial nucleus accumbens with the drug 5-CT caused a dose-dependent decrease in food intake, water intake, and locomotion in rats (Pratt et al., 2009). The current experiments sought to determine which of three serotonin receptor subtypes (5-HT1A, 5-HT1B, or 5-HT7) might be responsible for these consummatory and locomotor effects. Food-deprived rats were given 2-h access to rat chow after stimulation of nucleus accumbens 5-HT1A, 5-HT1B, or 5-HT7 receptors, or blockade of the 5-HT1A or 5-HT1B receptors. Stimulation of 5-HT1A receptors with 8-OH-DPAT (at 0.0, 2.0, 4.0, and 8.0 μg/0.5 μl/side) caused a dose-dependent decrease in food and water intake, and reduced rearing behavior but not ambulation. In contrast, rats that received the 5-HT1B agonist CP 93129 (at 0.0, 1.0, 2.0 and 4.0 μg/0.5 μl/side) showed a significant dose-dependent decrease in water intake only; stimulation of 5-HT7 receptors (AS 19; at 0.0, 1.0, and 5.0 μg/0.5 μl/side) decreased ambulatory activity but did not affect food or water consumption. Blockade of 5-HT1A or 5-HT1B receptors had no lasting effects on measures of food consumption. These data suggest that the food intake, water intake, and locomotor effects seen after medial nucleus accumbens injections of 5-CT are due to actions on separate serotonin receptor subtypes, and contribute to growing evidence for selective roles of individual serotonin receptors within the nucleus accumbens on motivated behavior.
authors.affiliation: Department of Psychology, Wake Forest University, Winston-Salem, NC, United States. Electronic address: kac64@duke.edu.
authors.forename: Kara A
authors.initials: KA
authors.lastname: Clissold
authors.forename: Eugene
authors.initials: E
authors.lastname: Choi
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Pratt
mesh_terms: D000818:Animals; D004327:Drinking Behavior / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000145:classification / Q000502:physiology*; D014867:Water
chemical_list: D011985:Receptors, Serotonin; D014867:Water
keywords: Feeding; Food intake; Motivation; Nucleus accumbens; Serotonin; Serotonin receptors