Long-Lasting Metabolic Imbalance Related to Obesity Alters Olfactory Tissue Homeostasis and Impairs Olfactory-Driven Behaviors

Obesity is associated with chronic food intake disorders and binge eating. Food intake relies on the interaction between homeostatic regulation and hedonic signals among which, olfaction is a major sensory determinant. However, its potential modulation at the peripheral level by a chronic energy imbalance associated to obese status remains a matter of debate. We further investigated the olfactory function in a rodent model relevant to the situation encountered in obese humans, where genetic susceptibility is juxtaposed on chronic eating disorders. Using several olfactory-driven tests, we compared the behaviors of obesity-prone Sprague-Dawley rats (OP) fed with a high-fat/high-sugar diet with those of obese-resistant ones fed with normal chow. In OP rats, we reported 1) decreased odor threshold, but 2) poor olfactory performances, associated with learning/memory deficits, 3) decreased influence of fasting, and 4) impaired insulin control on food seeking behavior. Associated with these behavioral modifications, we found a modulation of metabolism-related factors implicated in 1) electrical olfactory signal regulation (insulin receptor), 2) cellular dynamics (glucorticoids receptors, pro- and antiapoptotic factors), and 3) homeostasis of the olfactory mucosa and bulb (monocarboxylate and glucose transporters). Such impairments might participate to the perturbed daily food intake pattern that we observed in obese animal

EFFECT OF AMBIENT TEMPERATURE ON FOOD, NITROGEN AND ENERGY INTAKE OF THE FIELD-VOLE, MICROTUS ARVALIS, UNDER DIFFERENT CONDITIONS OF DAYLIGHT RATIO AND FEEDING

International audienc

Effects of timed melatonin infusions and lesions of the suprachiasmatic nuclei on prolactin and progesterone secretions in pregnant or pseudopregnant mink (Mustela vison)

International audienc

Endogenous circannual rhythms and photorefractoriness of testis activity, moult and prolactin concentrations in mink (Mustela vison)

International audienc

Distribution of arginine-vasopressin and vasoactive intestinal peptide messenger RNA in the suprachiasmatic nucleus of the sheep

International audienc

Vasoactive intestinal polypeptide in the suprachiasmatic nucleus of the mink (Mustela vison) could play a key role in photic induction

International audienc

Plasma levels of cortisol and oxytocin, and uterine activity after cervical artificial insemination in the ewe

International audienc

Plasma levels of cortisol and oxytocin, and uterine activity after cervical artificial insemination in the ewe

The objective was to compare in the ewe the effects of easy and difficult procedures for artificial insemination (AI) (as related to rapid or poor accessibility of the cervix, respectively) on plasma cortisol (CORT) and oxytocin (OT), and uterine motility. All AI were simulated using a catheter empty of semen to study genital and environmental stimuli only. In experiment 1, 40 ewes were sampled after AI, and whether it was an easy or difficult procedure was reported for each animal. While CORT concentrations rose to a similar amount in all ewes, whatever the AI procedure, a significant OT response occurred after a difficult procedure only ($n = 18$) (17.4 $\pm$ 1.7 versus 12.7 $\pm$ 0.7 pg$\cdot$mL$^{-1}$ before AI, $p < 0.05$). In experiment 2, uterine activity was monitored in 4 ewes using an implantable telemetric transmitter equipped with an intrauterine pressure catheter. An increased uterine activity occurred during 2 $\pm$ 1 min after an easy AI ($n = 5$), whereas the evoked activity lasted for 15 $\pm$ 4 min after a difficult AI ($p < 0.001$, $n = 7$). A similar long-lasting response occurred after OT administration (100 mIU, i.v.). We concluded that the increase in uterine motility after a difficult AI resulted from a reflex release of OT, and not to a “stress” effect