Histamine H1-receptors differentially mediate the action of amylin on hypothalamic neurons in control and in overweight rats.

The hypothalamic arcuate, dorsomedial and paraventricular nuclei are involved in regulation of body weight and food intake and contain binding sites for the anorexigenic amylin. Effects of amylin on medial arcuate and paraventricular neurons studied in adult rats overweight through early postnatal overfeeding in small litters (SL) differed from those of control litters (CL). Now we observed that also dorsomedial neurons respond differentially to this satiety signal.

Insulin resistance of hypothalamic arcuate neurons in neonatally overfed rats.

Rats exposed to early postnatal overfeeding by rearing in small litters become hyperphagic, hyperleptinemic, and hyperinsulinemic throughout later life. Medial arcuate neurons are involved in body weight regulation. They were tested in brain slices of control and small-litter rats concerning differences in responses to insulin.

GABAA receptor antagonists prevent abnormalities in leptin, insulin and amylin actions on paraventricular hypothalamic neurons of overweight rats.

The hypothalamic regulatory system of body weight which develops in rats during critical periods of early postnatal life seems to express plastic changes depending on nutrition at that time. Adult rats previously exposed to early postnatal overnutrition by raising them in small litters become persistently predisposed to overweight, hyperphagia and hyperleptinaemia. The hypothesis was raised that feeding-related peptides could be involved through altered effects on neuronal activity of the regulatory systems of such rats.

Action of prolactin, prolactin-releasing peptide and orexins on hypothalamic neurons of adult, early postnatally overfed rats.

Objectives: Hypothalamic neurons of rats overweight due to early postnatal overfeeding (SL) differ from those of control rats in their responses to feeding relevant hormones like leptin or insulin. The question arose whether prolactin and prolactin-releasing peptide (PrRP) express also differential action in SL rats. These peptides are described to have an effect on food intake and body weight regulation.

The main effect of cocaine- and amphetamine-regulated transcript (CART) peptide on hypothalamic neuronal activity depends on the nutritional state of rats.

Objectives: The anorectic and catabolic action of CART is primarily mediated by the hypothalamus. The study proved the hypothesis that neurons of the hypothalamic regulatory system of body weight differentially react to CART in dependence of the nutritional state of the animal: overweight, fed or short-term fasting.

Design And Setting: Single unit activity was extracellularly recorded in brain slices.

Arcuate neurons of overweight rats differ in their responses to amylin from controls.

Amylin and ghrelin are hormones produced, respectively, in pancreas and stomach. They have a central action on food intake and body weight. Possible changes in their effect on hypothalamic neuronal activity were investigated in overweight rats previously subjected to early postnatal overnutrition compared to controls.

Hypothalamic neurons of postnatally overfed, overweight rats respond differentially to corticotropin-releasing hormones.

Adult overweight rats previously subjected to early postnatal overnutrition in small litters are hyperphagic, hyperleptinemic and differ in emotional behaviour from rats of control litters. We proved the hypothesis that neurons of the hypothalamic regulatory system of body weight differentially react to peptides of the corticotropin-releasing factor (CRF) family in these overweight rats. Single unit activity was recorded in brain slices.

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.

Altered neuronal responses to feeding-relevant peptides as sign of developmental plasticity in the hypothalamic regulatory system of body weight.

Neuronal plasticity during the critical postnatal period of development seems to promote a change in the function of the hypothalamic regulatory system of body weight. Rats raised in small litters (SL) of only three pups per mother compared to ten or twelve in control litters (CL) gain significantly more weight than normal rats till weaning and are overweight also in later life. These rats are known to express hyperleptinemia, hyperglycemia and hyperinsulinemia.

Altered responses to orexigenic (AGRP, MCH) and anorexigenic (alpha-MSH, CART) neuropeptides of paraventricular hypothalamic neurons in early postnatally overfed rats.

Food intake and energy expenditure are regulated by neuropeptides in the hypothalamus. While cocaine- and amphetamine-regulated transcript (CART) peptide and melanocortins such as alpha-melanocyte-stimulating hormone (alpha-MSH) are anorexigenic and increase energy expenditure, the endogenous melanocortin receptor antagonist agouti gene-related protein (AGRP), melanin-concentrating hormone (MCH) and neuropeptide Y (NPY) are orexigenic, anabolic peptides. Alterations in the regulatory balance may promote excessive weight gain.

Hypothalamic ventromedial and arcuate neurons of normal and postnatally overnourished rats differ in their responses to melanin-concentrating hormone.

Melanin-concentrating hormone (MCH) is a neuropeptide involved in regulation of food intake and body weight. The study aimed to detect possible differences in responses of hypothalamic ventromedial and arcuate neurons to MCH, depending on the short-term nutritional state (fed versus food-deprived) and on the long-term state in overweight rats due to early postnatal overnutrition. The effect of MCH on a single-unit activity was studied in brain slices of normal and overweight rats.

Differential response to NPY of PVH and dopamine-responsive VMH neurons in overweight rats.

Neuronal responses to neuropeptide Y and dopamine were recorded in brain slices of hypothalamic paraventricular (PVH) and ventromedial (VMH) nuclei in normal and hyperphagic overweight rats reared in small litters of three pups. NPY significantly activated PVH neurons of normal rats, but inhibited neurons of overweight rats. In the VMH, a significantly higher coincidence of inhibition induced by NPY and dopamine was found in overweight rats.

Increased inhibition by agouti-related peptide of ventromedial hypothalamic neurons in rats overweight due to early postnatal overfeeding.

Melanocortins, e.g. alpha-melanocyte stimulating hormone, are involved in the central nervous regulation of body weight.

Differential involvement of dopamine D1 and D2 receptors and inhibition by dopamine of hypothalamic VMN neurons in early postnatally overfed juvenile rats.

Dopamine is among the neurotransmitters involved in central regulation of food intake, and body weight control. To study possible changes in neuronal responses to dopamine, single unit activity of the ventromedial hypothalamic nucleus (VMN) was recorded in brain slices of normal and obese rats. The latter had developed overweight throughout juvenile life (p < 0.