Junk food diet-induced obesity increases D2 receptor autoinhibition in the ventral tegmental area and reduces ethanol drinking

Abstract

Similar to drugs of abuse, the hedonic value of food is mediated, at least in part, by the mesostriatal dopamine (DA) system. Prolonged intake of either high calorie diets or drugs of abuse both lead to a blunting of the DA system. Most studies have focused on DAergic alterations in the striatum, but little is known about the effects of high calorie diets on ventral tegmental area (VTA) DA neurons. Since high calorie diets produce addictive-like DAergic adaptations, it is possible these diets may increase addiction susceptibility. However, high calorie diets consistently reduce psychostimulant intake and conditioned place preference in rodents. In contrast, high calorie diets can increase or decrease ethanol drinking, but it is not known how a junk food diet (cafeteria diet) affects ethanol drinking. In the current study, we administered a cafeteria diet consisting of bacon, potato chips, cheesecake, cookies, breakfast cereals, marshmallows, and chocolate candies to male Wistar rats for 3–4 weeks, producing an obese phenotype. Prior cafeteria diet feeding reduced homecage ethanol drinking over 2 weeks of testing, and transiently reduced sucrose and chow intake. Importantly, cafeteria diet had no effect on ethanol metabolism rate or blood ethanol concentrations following 2g/kg ethanol administration. In midbrain slices, we showed that cafeteria diet feeding enhances DA D2 receptor (D2R) autoinhibition in VTA DA neurons. These results show that junk food diet-induced obesity reduces ethanol drinking, and suggest that increased D2R autoinhibition in the VTA may contribute to deficits in DAergic signaling and reward hypofunction observed with obesity.

Emotional Eating in Pregnant Women during the COVID-19 Pandemic and Its Association with Dietary Intake and Gestational Weight Gain

“…Our finding was also consistent with studies conducted in Poland and Italia [ 21 , 22 ], which reported that people during lockdown time tend to snack more; however, the potential reasons were not mentioned in these two studies. As demonstrated in a previous study, the reinforcing/preference properties of palatable food are mediated by the mesostriatal dopamine system, which could produce addictive-like DAergic adaptations in the striatum [ 23 ]. The increasing consumption of foods with high hedonic value usually results in excess weight gain and increased risks of chronic conditions such as cardiovascular diseases and obesity [ 24 , 25 , 26 ].…”

Behavioral and Neurobiological Consequences of Hedonic Feeding on Alcohol Drinking

“…Cook et al evaluated home-cage oral ethanol drinking in male Wistar rats following 4 weeks of cafeteria diet consisting of high-calorie junk food (42% fat) and compared it to the chow (14% fat). While there were no baseline differences, alcohol drinking was significantly reduced in the cafeteria-diet group of rats [47]. Interestingly, reduced oral alcohol drinking has also been documented in golden hamsters maintained on a high-fat diet (72.6% calories from fat) compared to normal chow (12% calories from fat) [46].…”

“…While the studies mentioned above suggest a positive relationship between fat and alcohol intake, other studies have suggested no such relationship or blunted/reduced alcohol drinking following high-fat diet exposure [43][44][45][46][47][48]. For example, Takase et al .…”

Sucht und Adipositas: Können Nahrungsmittel abhängig machen?

“…Der Umstand, dass hohe Leptinspiegel Substanzcraving und -konsum eher reduzieren, steht im Einklang mit Berichten über einen inversen Zusammenhang zwischen hohem BMI und der Wahrscheinlichkeit aktuell illegale Substanzen zu konsumieren [86] sowie dem Risiko einer Abhängigkeitserkrankung [87]. In diesem Zusammenhang konnte auch gezeigt werden, dass hohes Körpergewicht respektive Adipositas mit einer geringeren Wahrscheinlichkeit zu Rauchen [88], Alkohol (im Tierversuch [89]) oder Marihuana [90] zu konsumieren assoziiert ist. Komplementär hierzu führen Maßnahmen die den BMI und den Leptinspiegel senken zu einer erhöhten Sensitivität gegenüber Psychostimulanzien [91,92].…”