A maternal “junk‐food” diet reduces sensitivity to the opioid antagonist naloxone in offspring postweaning

Abstract

Perinatal exposure to a maternal “junk‐food” diet has been demonstrated to increase the preference for palatable diets in adult offspring. We aimed to determine whether this increased preference could be attributed to changes in μ‐opioid receptor expression within the mesolimbic reward pathway. We report here that mRNA expression of the μ‐opioid receptor in the ventral tegmental area (VTA) at weaning was 1.4‐fold (males) and 1.9‐fold (females) lower in offspring of junk‐food (JF)‐fed rat dams than in offspring of dams fed a standard rodent diet (control) (P<0.05). Administration of the opioid antagonist naloxone to offspring given a palatable diet postweaning significantly reduced fat intake in control offspring (males: 7.7±0.7 vs. 5.4±0.6 g/kg/d; females: 6.9±0.3 vs. 3.9±0.5g/kg/d; P<0.05), but not in male JF offspring (8.6±0.6 vs. 7.1±0.5g/kg/d) and was less effective at reducing fat intake in JF females (42.2±6.0 vs. 23.1 ±4.1% reduction, P<0.05). Similar findings were observed for total energy intake. Naloxone treatment did not affect intake of standard rodent feed in control or JF offspring. These findings suggest that exposure to a maternal junk‐food diet results in early desensitization of the opioid system which may explain the increased preference for junk food in these offspring.—Gugusheff, J. R., Ong, Z. Y., Muhlhausler, B. S. A maternal “junk‐food” diet reduces sensitivity to the opioid antagonist naloxone in offspring postweaning. FASEB J. 27, 1275–1284 (2013). http://www.fasebj.org

Pregnancy, obesity and insulin resistance: maternal overnutrition and the target windows of fetal development

“…As the opioid system is known to have an important role in promoting the intake of palatable foods in adults, this could explain the increased preference for sucrose and fat displayed by these offspring. The involvement of the opioid system in the programming of food intake and preference is supported by recent studies in our laboratory, in which we found that the expression of the μ-opioid receptor in a key region of the central reward system, the ventral tegmental area, was lower at weaning in offspring exposed to a maternal palatable diet before birth and during the suckling period [58]. Importantly, we also demonstrated that this had functional consequences for the regulation of opioid signaling in these offspring, since those offspring exposed to the palatable diet in early life were less sensitive to the effect of the μ-opioid receptor antagonist, naloxone, in suppressing palatable food intake in the immediate postweaning period [58].…”

Changes in mu-opioid receptor expression and function in the mesolimbic system after long-term access to a palatable diet

“…At weaning, the expression of mRNA for the mu-opioid receptor was significantly lower in male offspring of mothers fed a cafeteria diet compared to the offspring of chow-fed mothers (Gugusheff et al, 2013). In contrast, 14-week-old male offspring from mothers fed high-fat chow had increased mu-opioid receptor mRNA in the VTA (Grissom et al, 2014).…”

“…Behaviours associated with reductions in mu-opioid receptor signalling, such as reduced preference for sucrose and reduced consumption of fat relative to chow, are inconsistent with weight gain. In addition, a reduction in mu-opioid receptors may decrease the efficacy of mu-opioid receptor antagonists to inhibit food intake (Gugusheff et al, 2013).…”

The food environment, its effects on dietary consumption, and potential for measurement within agriculture-nutrition interventions

“…In the typical pattern of dietary acculturation, the diets of immigrants adapt to the new country; in the U.S., diet quality of most immigrant groups declines measurably upon acculturation (Satia-Abouta et al 2002). Some research shows that dietary acculturation has multi-generational effects at the biological level, as tastes develop starting from young childhood and even in the womb (Gugusheff et al 2013). So, over time, a mutually-reinforcing cycle may occur whereby dietary patterns adapt to the lack of availability of fresh foods, and demand for healthy diets declines.…”