Hypothalamic Histamine Research Articles

New frontier of hypothalamic histamine: satiation and energy balance

New frontier of hypothalamic histamine: satiation and energy balance

Hypothalamic histamine regulates feeding suppression induced by 2-deoxy- d-glucose

Hypothalamic histamine regulates feeding suppression induced by 2-deoxy- d-glucose

Neuronal glucoprivation activates turnover of hypothalamic histamine in the rat

Neuronal glucoprivation activates turnover of hypothalamic histamine in the rat

Zucker obese rats: defect in brain histamine control of feeding

Manipulation of hypothalamic histamine produced different effects on feeding between the Zucker obese (fa/fa) and their lean littermate rats (Fa/−). Infusion of a histamine H1-receptor antagonist into the third cerebroventricle elicited feeding in the lean and Wistar King A rats, but it did not affect feeding in the obese rats. To enhance hypothalamic neuronal histamine, thioperamide, an H3-receptor antagonist, was similarly infused. The lean and Wistar rats decreased their food intake after the infusion, but thioperamide produced no significant effect on feeding in the obese rats. Infusion of histamine into the third cerebroventricle mimicked the effects of thioperamide on feeding: reduction of food intake in the lean and Wistar rats, but no significant change in the obese rats. Hypothalamic histamine of the obese rats (0.430 nmol/g) was significantly lower than the lean (1.209 nmol/g) and Wistar rats (4.838 nmol/g). The histamine concentration of the cerebral cortex in the obese rats was also lower than the non-obese animals. The results indicate that the feeding abnormality of Zucker obese rats may be at least due to disturbance of histamine suppressive signals both at presynaptic and postsynaptic levels.

Hypothalamic histamine and liver insufficiency

Evidence is presented that the rise in hypothalamic histamine after portocaval anastomosis is due to itsde novo synthesis resulting from increased influx of histidine into brain.

Increased neuronal histamine in thiamine-deficient rats

Previous studies have indicated that thiamine deficiency is associated with clearly elevated histamine concentrations in the rat hypothalamus, whereas other brain regions contain normal amounts of the amine. The purpose of this study was to find out if the increased hypothalamic histamine concentrations are due to increased numbers of mast cells or changes in neuronal histamine stores.

Aminoglucose-induced feeding suppresion due to hypothalamic neuronal histamine

Aminoglucose-induced feeding suppresion due to hypothalamic neuronal histamine

O-476 - Hypothalamic histamine modulates delayed suppression of feeding following administration of 2-deoxy-D-glucose

O-476 - Hypothalamic histamine modulates delayed suppression of feeding following administration of 2-deoxy-D-glucose

Histaminergic control of energy balance in rats

Manipulating neuronal histamine in the hypothalamus, its effects on brain functions were assessed in nonobese normal rats and Zucker rats. Alpha-fluoromethylhistidine (FMH), an inhibitor of histamine synthesis, induced feeding dose-dependently after 2.24 μmol infusion at 1100 h, when hypothalamic histamine was normally high. This dose of FMH selectively decreased hypothalamic histamine, but not other neurotransmitters. Thioperamide, an antagonist of autoinhibitory H 3-receptors, decreased food intake after infusion at 1940 h, when hypothalamic histamine was normally low. Bilateral microinfusion of 224 nmol FMH or 26 nmol chlorpheniramine, an H 1-antagonist, into the ventromedial hypothalamus (VMH) and the paraventricular nucleus (PVN), elicited feeding. However, Zucker obese rats showed no significant responses to chlorpheniramine, thioperamide or histamine. Concentration of their hypothalamic histamine was excessively lower than that of the nonobese. Contents of hypothalamic histamine were lowered at 4°C and raised at 31°C. FMH attenuated increase in histamine, and then disrupted adaptive behavior. These findings indicate that neuronal histamine may convey the suppressive signal of food intake through H 1-receptors in the VMH and/or the PVN, and play critical roles in homeostatic control of adaptive behavior.

Histidine decarboxylase inhibition induced by α-fluoromethylhistidine provokes learning-related hypokinetic activity

The influence of brain histamine (HA) on learning and memory is not well understood, although some reports indicate that HA improves memory consolidation. We have studied the effects of alpha-fluoromethylhistidine (FMH) (100 mg/Kg, i.p.), which reduced by 60-80% the concentration of hypothalamic HA, on rat locomotor activity (LA) and learning in several experimental conditions in a computerized system. FMH reduced LA in an open field paradigm (OFP) 3 h after injection and tended to inhibit motor habituation after a 3-day trial. In a maze paradigm (MP), where the animals had to learn to avoid a foot-shock (1 mA), FMH reduced LA, rearing (2F), and jumping activity (JA). The peripheral administration of HA to control-trained rats reduced a learning index (N/Sts ratio) by 50%. According to these results, FMH diminished LA, 2F, and JA with no effect on habituation in MP. These observations might indicate that a moderate reduction in the levels of brain HA might enhance attention in solving visuo-spatial tasks under stressful stimuli.

O-031 - Ginsenoside Rg1 modulates adaptive behavior via hypothalamic histamine at a high temperature.

O-031 - Ginsenoside Rg1 modulates adaptive behavior via hypothalamic histamine at a high temperature.

Post-fasting anorexia in rats is governed by enhanced activity of hypothalamic histamine

Post-fasting anorexia in rats is governed by enhanced activity of hypothalamic histamine

Hypothalamic histamine modulates delayed suppression of feeding following infusion of 2-deoxy-D-glucose

Hypothalamic histamine modulates delayed suppression of feeding following infusion of 2-deoxy-D-glucose

Hypothalamic histamine regulates the light-dark cycle of feeding in rats

Hypothalamic histamine regulates the light-dark cycle of feeding in rats

Hypothalamic neuronal histamine modulates ad libitum feeding by rats

Manipulating histamine endogenously, its effects on brain functions were assessed in rats. α-Fluoromethylhistidine (FMH), an inhibitor of histamine synthesis, elicited feeding ( P < 0.01) after intra-third cerebroventricular infusion at the early light phase when hypothalamic histamine was normally highest. No periprandial drinking was observed. The effect of FMH was attenuated, and thioperamide, an antagonist of auto-inhibitory effects on both histamine synthesis and release at presynaptic H 3-receptor, conversely suppressed food intake ( P < 0.05), when these probes were carried out during the minimum histamine level early in the dark period. Bilateral microinfusion of FMH into the ventromedial hypothalamus (VMH) and the paraventricular nucleus (PVN) selectively induced feeding, but the infusion into the remaining sites of the hypothalamus had no effect. These data show that neuronal histamine plays a physiological role in feeding suppression through the VMH and the PVN in the rat.

Effects of GABA on hypothalamic histamine neurons in vitro

Effects of GABA on hypothalamic histamine neurons in vitro

Hypothalamic histamine modulates adaptive behavior of rats at high environmental temperature

Histamine content in the rat hypothalamus was lower at 4 degrees C and higher at 31 degrees C compared to that at 21 degrees C. Pretreatment with alpha-fluoromethylhistidine, a 'suicide' inhibitor of histamine decarboxylase, attenuated both the increased level of hypothalamic histamine and rat adaptive behavior at 31 degrees C. Increase of histamine content in the hypothalamus appears to be an important factor contributing to rat adaptive behavior to high environmental temperature.

Hypothalamic histamine modulates adaptive behavior of rats in high environmental temperature

Hypothalamic histamine modulates adaptive behavior of rats in high environmental temperature

Effects of Thiamine Administration on Hypothermia and Hypothalamic Histamine Levels in Dietary-Induced Thiamine Deficient Rats

The rats maintained on a thiamine-deficient diet for 30 days showed hypothermia, and their histamine levels increased significantly in both the anterior and posterior hypothalamus. When these rats were administered, thiamine disulfide and/or provided with thiamine-added diet for a further 30 days, the rats recovered from hypothermia, and histamine levels were decreased to the normal level. Thus, it is probable that the increased histamine levels in the hypothalamus, especially those in its anterior region, are closely related to the hypothermia in thiamine-deficient rats.

Hypothalamic histamine modulates adaptive behavior of rats in high environmental temperature

Hypothalamic histamine modulates adaptive behavior of rats in high environmental temperature