Microinjections of SCH 23390 in the ventral tegmental area reduce operant responding under a progressive ratio schedule of food reinforcement in rats

2005 ◽  
Vol 1033 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Ruth Sharf ◽  
David Y. Lee ◽  
Robert Ranaldi
Keyword(s):  
Ventral Tegmental Area ◽  
Food Reinforcement ◽  
Sch 23390 ◽  
Progressive Ratio ◽  
Ratio Schedule ◽  
Progressive Ratio Schedule ◽  
Operant Responding ◽  
Ventral Tegmental

scholarly journals Glucagon-Like Peptide-1 (GLP-1) and 5-Hydroxytryptamine 2c (5-HT2c) Receptor Agonists in the Ventral Tegmental Area (VTA) Inhibit Ghrelin-Stimulated Appetitive Reward

2019 ◽  
Vol 20 (4) ◽  
pp. 889 ◽  
Author(s):  
Erin Howell ◽  
Hannah Baumgartner ◽  
Lia Zallar ◽  
Joaquín Selva ◽  
Liv Engel ◽  
...  
Keyword(s):  
Ventral Tegmental Area ◽  
Receptor Agonist ◽  
Food Reinforcement ◽  
Progressive Ratio ◽  
Sprague Dawley ◽  
Operant Responding ◽  
Orexigenic Peptide ◽  
Glucagon Like Peptide ◽  
Ventral Tegmental ◽  
Glucagon Like Peptide 1

Current literature indicates that the orexigenic peptide ghrelin increases appetitive motivation via signaling in the mesolimbic reward system. Another gastric peptide, glucagon-like peptide-1 (GLP-1), and the neurotransmitter 5-hydroxytryptamine (5-HT), are both known to suppress operant responding for food by acting on key mesolimbic nuclei, including the ventral tegmental area (VTA). In order to investigate the interaction effects of ghrelin, GLP-1, and 5-HT within the VTA, we measured operant responding for sucrose pellets after the administration of ghrelin, the GLP-1 receptor agonist exendin-4 (Ex-4), and the 5-HT2c receptor agonist Ro60-0175 in male Sprague-Dawley rats. Following training on a progressive ratio 3 (PR3) schedule, animals were first injected with ghrelin into the VTA at doses of 3 to 300 pmol. In subsequent testing, separate rats were administered intraperitoneal (IP) Ex-4 (0.1–1.0 µg/kg) or VTA Ex-4 (0.01–0.1 µg) paired with 300 pmol ghrelin. In a final group of rats, the 5-HT2c agonist Ro60-0175 was injected IP (0.25–1.0 mg/kg) or into the VTA (1.5–3.0 µg), and under both conditions paired with 300 pmol ghrelin delivered into the VTA. Our results indicated that ghrelin administration increased operant responding for food reward and that this effect was attenuated by IP and VTA Ex-4 pretreatment as well as pre-administration of IP or VTA Ro60-0175. These data provide compelling evidence that mesolimbic GLP-1 and serotonergic circuitry interact with the ghrelinergic system to suppress ghrelin’s effects on the mediation of food reinforcement.

scholarly journals Ventral tegmental area orexin 1 receptors promote palatable food intake and oppose postingestive negative feedback

2016 ◽  
Vol 311 (3) ◽  
pp. R592-R599 ◽  
Author(s):  
Sarah J. Terrill ◽  
Kellie M. Hyde ◽  
Kristen E. Kay ◽  
Hayden E. Greene ◽  
Calyn B. Maske ◽  
...  
Keyword(s):  
Food Intake ◽  
Ventral Tegmental Area ◽  
Negative Feedback ◽  
Burst Size ◽  
Progressive Ratio ◽  
Ratio Schedule ◽  
Orexin A ◽  
Multiple Test ◽  
Seeking Behavior ◽  
Ventral Tegmental

Hypothalamic orexin neurons project to numerous brain areas, including the ventral tegmental area (VTA), which is involved in motivation and food-seeking behavior. Here we address how exogenously administered orexin-A and endogenous orexin 1 receptor (OX1R) activation in the VTA affects feeding behavior. We hypothesized that orexin-A and OX1R antagonist SB334867 delivered to the VTA, at doses that were subthreshold for effect when injected into the ventricle, would affect intake of palatable foods in multiple test situations. We first used a hedonic feeding model in which satiated rats selectively consume a high-fat diet (HFD). Intra-VTA orexin-A stimulated additional consumption of chow and increased HFD intake in this model. In ad libitum-fed rats given daily 30-min test sessions, intra-VTA orexin-A also increased intake of HFD and 0.1 M sucrose. Further analysis of licking patterns revealed that that VTA orexin-A increased meal size and licking burst size only toward the end of the meal. Consistent with this finding, a subthreshold dose of VTA orexin-A prevented intake suppression induced by gastrointestinal nutrient infusion. Surprisingly, intra-VTA orexin-A had no effect on operant responding for sucrose pellets on a progressive ratio schedule of reinforcement. A role for endogenous VTA OX1R stimulation is supported by our finding that bilateral VTA injection of the selective OX1R antagonist SB334867 suppressed 0.1 M sucrose intake. Together, our data suggest that OX1R activity in the VTA facilitates food intake, potentially by counteracting postingestive negative feedback that would normally suppress feeding later in a meal.

Food quality and cognition: Effects of a purified, refined diet on performance on a progressive ratio schedule in rats

2013 ◽  
Author(s):  
Aaron P. Blaisdell ◽  
Matthew Yan Lam Lau ◽  
Cynthia Fast ◽  
Katie Telminova ◽  
Boyang Fan ◽  
...  
Keyword(s):  
Food Quality ◽  
Progressive Ratio ◽  
Ratio Schedule ◽  
Progressive Ratio Schedule

Effects of clonidine on progressive ratio schedule performance in Fmr1 knockout mice

2021 ◽  
Author(s):  
Craige C. Wrenn ◽  
Eric French ◽  
Dustin Baker ◽  
Randall McCallian ◽  
Ryan Kirk ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Progressive Ratio ◽  
Ratio Schedule ◽  
Progressive Ratio Schedule ◽  
Schedule Performance
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