Gender Affects Rats' Central Nervous System Histaminergic Responses to Dietary Manipulation

Abstract

The histaminergic system (histamine and its H1-receptor) of the central nervous system has been implicated in control of food intake. The reported studies were designed to examine the effects of food restriction and very low (1%) protein diets on central nervous system H1-receptors in male and female rats. In a series of experiments, groups of rats were freely fed a 25% protein diet, a 1% protein diet, or fed the 25% protein diet at 4 g/100 g body weight for 14-20 d. When freely fed 25% protein diets, females had higher whole-brain H1-receptor binding than males on d 1 (female 122.36 +/- 4.53 and male 65.78 +/- 3.82 pmol/g protein; P < 0.001). Changing diets affected central H1-receptor binding in both males and females (P < 0.003). When rats were fed both restricted levels of food and 1% protein diets, the receptor binding of males increased by d 5 whereas that of females decreased by d 5 (P < 0.001). When fed 1% protein diets, females had decreased H1-receptor binding (98.4 +/- 2.38 pmol/g protein) and that in males increased to 119.81 +/- 5.09 pmol/g protein. After 15 d, females had eaten significantly more food than males: females 166 +/- 4.9 g, males 124 +/- 1.9 g (P< 0.0007). Males had a significantly greater weight loss than females: males -28.8 +/- 2.6 g, females -17.08 +/- 0.97 g (P < 0.0007). When fed restricted diets, females had decreased H1-receptor binding (93.81 +/- 5.58 pmol/g) whereas binding in males increased to 111.27 +/- 8.55 pmol/g. Preliminary saturation binding studies indicated that restricted food intake lowered receptor density (females consuming 25% protein: 715 +/- 30 pmol/g protein; female restricted: 467 +/- 28 pmol/g protein, P < 0.05), while 1% protein increased receptor sensitivity, i.e., lowered KD (males consuming 25% protein: 15.3 +/- 1.8 nmol; males fed low protein: 2.8 +/- 0.27 nmol). This study suggests that dietary manipulation affects central H1-receptor binding in a gender-specific manner, thereby modulating central histaminergic activity during food or protein deficit.

Effect of histaminergic manipulation on weight in obese adults: a randomized placebo controlled trial

“…In animals, gender differences were observed in the central nervous system histamine receptor response to dietary manipulations. 25,26 The histaminergic nerve cell bodies in the central nervous system are exclusively located in the tuberomammillary nucleus of the posterior hypothalamus. 27 These cells project their axons mainly to two areas: the paraventricular nucleus and ventromedial hypothalamus (VMH).…”

Increased density of brain histamine H1 receptors in rats with portacaval anastomosis and in cirrhotic patients with chronic hepatic encephalopathy

“…9,21,22 In male rats, food intake is inversely correlated with the density of brain histamine H 1 receptors. 38 Portacaval surgery results in a significant weight loss immediately after the procedure. However, 1 month after surgery, the weight-gain curves are re-established, 7 and at 6 months, the time at which the animals in the present study were killed, the total food intake and the weight-gain curves are normal.…”

The neuroregulation of food intake: The effect of sex on meal selection patterns and the influence of diet on central H1 receptor binding in female SD rats

“…Low protein intake correlates with raised His levels accompanied by increased levels of HA and HA binding, which apparently appears to be sex-specific. Female rats did not have the same H 1 receptor binding response when fed a low protein diet as male rats [10]. Female rats initially exhibited decreased brain H 1 receptor binding on a low protein diet [10].…”

“…Female rats did not have the same H 1 receptor binding response when fed a low protein diet as male rats [10]. Female rats initially exhibited decreased brain H 1 receptor binding on a low protein diet [10]. Another dietary regimen which has a sex-specific effect on the histaminergic system is a restricted diet.…”