Dopaminergic and serotonergic changes in rabbit fetal brain upon repeated gestational exposure to diesel engine exhaust.

Limited studies in humans and in animal models have investigated the neurotoxic risks related to a gestational exposure to diesel exhaust particles (DEP) on the embryonic brain, especially those regarding monoaminergic systems linked to neurocognitive disorders. We previously showed that exposure to DEP alters monoaminergic neurotransmission in fetal olfactory bulbs and modifies tissue morphology along with behavioral consequences at birth in a rabbit model. Given the anatomical and functional connections between olfactory and central brain structures, we further characterized their impacts in brain regions associated with monoaminergic neurotransmission.

Interactions of Viral Proteins from Pathogenic and Low or Non-Pathogenic Orthohantaviruses with Human Type I Interferon Signaling.

Rodent-borne orthohantaviruses are asymptomatic in their natural reservoir, but they can cause severe diseases in humans. Although an exacerbated immune response relates to hantaviral pathologies, orthohantaviruses have to antagonize the antiviral interferon (IFN) response to successfully propagate in infected cells. We studied interactions of structural and nonstructural (NSs) proteins of pathogenic Puumala (PUUV), low-pathogenic Tula (TULV), and non-pathogenic Prospect Hill (PHV) viruses, with human type I and III IFN (IFN-I and IFN-III) pathways.

Artificial milk preference of newborn lambs is prenatally influenced by transfer of the flavor from the maternal diet to the amniotic fluid.

The present study examined in lambs whether exposure to flavors derived from pregnant mother's diet and transferred to amniotic fluid (AF) could induce a preference for artificial milk containing one of these flavors. To test this hypothesis, cumin was added to the maternal diet in the last month of gestation. Preference for artificial milk containing p-cymene, one of the chemosensory compounds of cumin, was tested within the first two days after birth in maternally deprived lambs born from mothers fed a cumin-flavored diet (Cumin group), or an unflavored diet (Control group).

Effect of environmental exposure to a maternally-learned odorant on anxiety-like behaviors at weaning in mice.

Early sensory experience, such as exposure to maternal or other environmental factors, is considered to influence neurocognitive development and behaviors. In many species, exposure to odorants during pregnancy or lactation impacts the morpho-functional development of the olfactory circuitry with changes in olfactory sensitivity, feeding behavior and food preferences at birth or later. However, few studies have investigated the impact of a perinatal exposure to odorants on the anxiety-like behavior of animals to stressfull stimuli.

Effect of Maternal Obesity and Preconceptional Weight Loss on Male and Female Offspring Metabolism and Olfactory Performance in Mice.

According to the "developmental origins of health and disease" (DOHaD) concept, maternal obesity predisposes the offspring to non-communicable diseases in adulthood. While a preconceptional weight loss (WL) is recommended for obese women, its benefits on the offspring have been poorly addressed. We evaluated whether preconceptional WL was able to reverse the adverse effects of maternal obesity in a mouse model, exhibiting a modification of foetal growth and of the expression of genes encoding epigenetic modifiers in liver and placenta.

Chronic perinatal odour exposure with heptaldehyde affects odour sensitivity and olfactory system homeostasis in preweaning mice.

Exposure to specific odorants in the womb during pregnancy or in the milk during early nursing is known to impact morpho-functional development of the olfactory circuitry of pups. This can be associated with a modification in olfactory sensitivity and behavioural olfactory-based preferences to the perinatally encountered odorants measured at birth, weaning or adult stage. Effects depend on a multitude of factors, such as odorant type, concentration, administration mode and frequency, as well as timing and mice strain.

Rat strains with different metabolic statuses differ in food olfactory-driven behavior.

In most species, food intake is influenced by olfactory cues and metabolic status can affect the olfactory function of animals and regulate feeding-related behaviors. We investigated whether modulation of the endocrine system that regulates or modifies energy balance affected the olfactory system by examining four rat strains, obese Zucker and obesity-resistant Lou/C rats and their counterparts. Such models were chosen because they differ largely in their energy status and in their insulin and leptin blood levels, two hormones known to impact olfactory behaviors.

Chronic restricted access to food leading to undernutrition affects rat neuroendocrine status and olfactory-driven behaviors.

Previous studies have demonstrated that olfactory-driven behaviors in rats are influenced by short-term caloric restriction, partly through the modulation of olfactory sensitivity by appetite-modulating hormones or peptides such as insulin and leptin. Here, we addressed the issue of a long-term modulation of their neuroendocrine status by evaluating the effect of chronic food restriction in rats following a limitation of the duration of daily food intake to 2 h (SF) instead of 8 h (LF) on the expression of insulin and leptin system in the olfactory mucosa and bulb and on olfactory behaviors. This restriction resulted in a one-third reduction in the daily food intake and a 25% reduction in the body weight of SF rats when compared to controls, and was accompanied by lower levels of triglycerides, glucose, insulin and leptin in SF rats.

Leptin-sensitive OBP-expressing mucous cells in rat olfactory epithelium: a novel target for olfaction-nutrition crosstalk?

Although odorant-binding proteins (OBP) are one of the most abundant classes of proteins in the mammalian olfactory mucus, they have only recently been ascribed a functional role in the detection of odorants by olfactory neurons. Among the three OBPs described in the rat, OBP-1f is mainly secreted by the lateral nasal glands (LNG) and Bowman's glands, and its expression is transcriptionally regulated by food deprivation in the olfactory mucosa, but not in LNG. Therefore, mucus composition might be locally regulated by hormones or molecules relevant to nutritional status.

Nutritional status modulates behavioural and olfactory bulb Fos responses to isoamyl acetate or food odour in rats: roles of orexins and leptin.

Food odours are major determinants for food choice, and their detection depends on nutritional status. The effects of different odour stimuli on both behavioural responses (locomotor activity and sniffing) and Fos induction in olfactory bulbs (OB) were studied in satiated or 48-h fasted rats. We focused on two odour stimuli: isoamyl acetate (ISO), as a neutral stimulus either unknown or familiar, and food pellet odour, that were presented to quiet rats during the light phase of the day.

Expression of insulin system in the olfactory epithelium: first approaches to its role and regulation.

Food odours are major determinants for food choice; their detection is influenced by nutritional status. Among different metabolic signals, insulin plays a major role in food intake regulation. The aim of the present study was to investigate a potential role of insulin in the olfactory mucosa (OM), using ex vivo tissues and in vitro primary cultures.

On a chip demonstration of a functional role for Odorant Binding Protein in the preservation of olfactory receptor activity at high odorant concentration.

The molecular mechanisms underlying odorant detection have been investigated using the chip based SPR technique by focusing on the dynamic interactions between transmembrane Olfactory Receptor OR1740, odorant ligands and soluble Odorant-Binding Protein (OBP-1F). The OR1740 present in the lipid bilayer of nanosomes derived from transformed yeasts specifically bound OBP-1F. The receptor preferential odorant ligand helional released bound OBP-1F from the OR-OBP complex, while unrelated odorants failed to do so.

Transcription profile analysis reveals that OBP-1F mRNA is downregulated in the olfactory mucosa following food deprivation.

Neuroanatomical data show that olfactory mucosa (OM) is a possible place for interactions between nutrition and smell. A combination of differential display mRNA analysis together with a macroarray screening was developed to identify transcripts that are differentially expressed in rat OM following food deprivation. Using this method, backed on a stringent statistical analysis, we identified molecules that fell into several Gene Ontology terms including cellular and physiological process, signal transduction, and binding.

Leptin and its receptors are present in the rat olfactory mucosa and modulated by the nutritional status.

Leptin is an adipocyte-derived cytokine that regulates body weight mainly via the long form of the leptin receptor (Ob-Rb). Leptin and its receptors are expressed in several tissues, suggesting that leptin might also be effective peripherally. We hypothesized that, as shown in taste cells, leptin and its receptors isoforms (Ob-Rs) could be present in the rat olfactory mucosa (OM).