Action of CCK and 5-HT on lateral hypothalamic neurons depends on early postnatal nutrition

Can breastfeeding affect the rest of our life?

The breastfeeding period is one of the most important critical windows in our development, since milk, our first food after birth, contains several compounds, such as macronutrients, micronutrients, antibodies, growth factors and hormones that benefit human health. Indeed, nutritional, and environmental alterations during lactation, change the composition of breast milk and induce alterations in the child's development, such as obesity, leading to the metabolic dysfunctions, cardiovascular diseases and neurobehavioral disorders. This review is based on experimental animal models, most of them in rodents, and summarizes the impact of an adequate breast milk supply in view of the developmental origins of health and disease (DOHaD) concept, which has been proposed by researchers in the areas of epidemiology and basic science from around the world. Here, experimental advances in understanding the programming during breastfeeding were compiled with the purpose of generating knowledge about the genesis of chronic noncommunicable diseases and to guide the development of public policies to deal with and prevent the problems arising from this phenomenon. This review article is part of the special issue on "Cross talk between periphery and brain".

Metabolic programming in the immediate postnatal life

The metabolic programming effects of nutritional modifications in the immediate postnatal life are increasingly recognized to independently contribute to the development of metabolic syndrome in later life. Adjustment of litter size in rodents has been used to induce either under- or overnourishment in the immediate postnatal life of the offspring. While undernourishment led to growth retardation in the offspring, overnourishment produced increased body weight gains, hyperinsulinemia and hyperleptinemia. Overnourishment during the suckling period induced several adaptations in the energy circuitry in the hypothalamus of the offspring predisposing them for the onset of obesity later in life. Another approach for a nutritional modification in the immediate postnatal period is the artificial rearing of newborn rat pups on a high-carbohydrate (HC) milk formula without changes in the total calorie availability. Hyperinsulinemia, immediately evident in the HC pups, persisted in the post-weaning period even after withdrawal of the HC milk. Significant alterations in pancreatic islets supported chronic hyperinsulinemia in the HC rats. Alterations in the gene expression of hypothalamic neuropeptides predisposing to hyperphagia were evident during the period of the HC dietary modification. The persistence of these hypothalamic adaptations supported the obese phenotype in adult HC rats. A transgenerational effect gave rise to the development of chronic hyperinsulinemia and adult-onset obesity in the offspring of the HC female rats. Other studies have shown that lactation by a diabetic, obese or malnourished mother resulted in predisposition for the onset of metabolic disorders in the offspring. These observations from animal studies on the metabolic programming effects due to altered nutritional experiences in the immediate postnatal life strongly suggest that altered feeding practices for infants (formula feeding and early introduction of infant foods) could contribute to the rising incidence of overweight/obesity in children and adults.

Critical determinants of hypothalamic appetitive neuropeptide development and expression: species considerations

Over the last decade there has been a striking increase in the early onset of metabolic disease, including obesity and diabetes. The regulation of energy homeostasis is complex and involves the intricate integration of peripheral and central systems, including the hypothalamus. This review provides an overview of the development of brain circuitry involved in the regulation of energy homeostasis as well as recent findings related to the impact of both prenatal and postnatal maternal environment on the development of these circuits. There is surprising evidence that both overnutrition and undernutrition impact the development of these circuits in a similar manner as well as having similar consequences of increased obesity and diabetes later in life. There is also a special focus on relevant species differences in the development of hypothalamic circuits. A deeper understanding of the mechanisms involved in the development of brain circuitry is needed to fully understand how the nutritional and/or maternal environments impact the functional circuitry as well as the behavior and physiological outcomes.

Altered action of dopamine and cholecystokinin on lateral hypothalamic neurons in rats raised under different feeding conditions

Single-unit activity was recorded in the lateral hypothalamus (LH) of adult Wistar rats anaesthetized with urethane. The rats were differently nourished till weaning by raising in small (SL), control (CL) or large litters (LL). They gained significantly different body weight leading to overweight in SL (mean: 428.4 g on day 90) and underweight in LL rats (mean 399.5 g) compared to CLs (414.5 g). The mean basal firing rate of LH neurons differed, it was lowest in SL and highest in LL rats. The proportion of neurons changing their firing rate by more than 30% in response to iontophoretically administered dopamine (DA) was significantly greater in SL (76%) than LL rats (54%). Effects of DA were significantly more often blocked by a D1 receptor antagonist in LL than CLs. The responsiveness to cholecystokinin (CCK) alone and coadministered with DA was also greater in SL than LL. Furthermore, the proportion of neurons inhibited by DA alone and in the presence of CCK was significantly greater in SL than LL rats. In conclusion, litter size and difference in nourishment during early postnatal development of rats seem to determine LH basal firing rate. The increased neuronal responsiveness to exogenous DA and CCK in neonatally overfed SL rats may indicate a decreased activity of these endogenous signals which normally contribute to limitation of energy intake.

Comportamento alimentar neonatal

Durante o período de aleitamento, aspectos do comportamento alimentar sofrem intensa transformação. Vários estudos descrevem, do nascimento ao desmame, as modificações nas ações comportamentais necessárias para aquisição do alimento pelo neonato. O controle desse comportamento também apresenta ajustes fisiológicos através da lactação, mudando de um padrão pré-absortivo, em período precoce, para pós-absortivo, próximo ao desmame. Devido a essas transformações, esse período torna-se vulnerável a agressões ambientais que podem influenciar o estabelecimento de padrões alimentares que estarão associados a patologias na vida adulta.

Maternal obesity alters adiposity and monoamine function in genetically predisposed offspring

The impact of maternal obesity on brain monoamine function in adult offspring of dams selectively bred to express diet-induced obesity (DIO) or diet resistance (DR) was assessed by making dams obese or lean during gestation and lactation. After 12 wk on chow and 4 wk on a 31% fat diet, offspring hypothalamic nucleus size and [(3)H]nisoxetine binding to norepinephrine transporters (NET) and [(3)H]paroxetine binding to serotonin transporters (SET) were measured. Offspring of obese DIO dams became more obese than all other groups, but maternal obesity did not alter weight gain in DR offspring (25). Maternal obesity was associated with 10-17% enlargement of ventromedial nuclei (VMN) and dorsomedial nuclei in both DIO and DR offspring. Offspring of obese DIO dams had 25-88% lower NET binding in the paraventricular nuclei (PVN), arcuate nuclei, VMN, and the central amygdalar nuclei, while offspring of obese DR dams had 43-67% higher PVN and 90% lower VMN NET binding and a generalized increase in SET binding across all hypothalamic areas compared with other groups. Thus maternal obesity was associated with alterations in offspring brain monoamine metabolism, which varied as a function of genotype and the development of offspring obesity.