下丘脑神经的研究进展

下丘脑位于间脑的腹侧部 ,构成第三脑室底壁和侧壁腹侧部 ,是重要的植物性神经的皮质下中枢 ,也是神经体液调节的关键部位。下丘脑含有许多重要的神经核团 ,这些神经核团涉及多种生理功能 ,共同管理一系列的代谢活动和内分泌活动 ,它们已经引起了国内、外神经解剖学者的普遍重视。因此 ,对这些神经核团的超微结构、神经纤维的支配等方面的研究 ,对于进一步探讨下丘脑的复杂功能具有重要意义。近年来研究较多的神经核团有 :视上核、室旁核、弓状核、交叉上核、下丘脑外侧核、室周核、视交叉上核。1　视上核视上核跨起视束的前段 ,横于内外侧…     

关于动物下丘脑部激素的介绍

1促性腺激素释放激素促性腺激素释放激素(GnRH),由下丘脑内侧视前区,下丘脑前部,弓状核和视交叉上核的神经核团分泌。哺乳动物下丘脑分泌的GnRH均为由9种氨基酸组成的直链式十肽,禽类、两栖类和鱼类的分子结构与哺乳类略有差异。下丘脑与垂体间没有直接的神经支配,而是通     

瘦素调节动物采食量及能量代谢的研究进展

下丘脑是动物机体能量代谢的调节中枢,其神经内分泌调节网络的中心环节是感受外周脂肪细胞分泌的瘦素所提供的能量贮存信号,调控下丘脑弓状核内相关蛋白和激素的表达水平,从而调节能量的摄入和消耗,维持机体能量代谢的稳态,能量的摄入离不开采食,而通过能量代谢的途径来控制采食量,尤其对于控制繁殖母猪体质量显的尤为重要.     

瘦素调节动物采食量及能量代谢的研究进展

下丘脑是动物机体能量代谢的调节中枢,其神经内分泌调节网络的中心环节是感受外周脂肪细胞分泌的瘦素所提供的能量贮存信号,调控下丘脑弓状核内相关蛋白和激素的表达水平,从而调节能量的摄入和消耗,维持机体能量代谢的稳态,能量的摄入离不开采食而通过能量代谢的途径来控制采食量,尤其对于控制繁殖母猪体重显的尤为重要.本文就对瘦素调节动...     

鸡端脑和下丘脑向面神经腹侧核的传出性纤维联系—HRP逆行追踪法

将２０％ＨＲＰ水溶液注射于鸡的面神经腹侧核，逆行追踪支配该部的有关主同位神经核团。结果于端，下丘脑和脑干内出现标记细胞，端脑内的标记细胞较多地出现于古纹状体，少量出现于旧纹状体腹侧与枕中脑束之间的区域，两群标记细胞形态上明显不同。下丘脑的标记细胞较多地出现于下丘脑后区，室旁核出现少量，个别散在于下丘脑其他区域。     

瘦素调节动物采食量及能量代谢的研究进展

下丘脑是动物机体能量代谢的调节中枢,其神经内分泌调节网络的中心环节是感受外周脂肪细胞分泌的瘦素所提供的能量贮存信号,调控下丘脑弓状核内相关蛋白和激素的表达水平,从而调节能量的摄入和消耗,维持机体能量代谢的稳态,能量的摄入离不开采食而通过能量代谢的途径来控制采食量,尤其对于控制繁殖母猪体重显的尤为重要。文章就对瘦素调节动物采食量以及能量代谢的最新研究机制作一综述。     

胰淀素调控生理机能的研究进展

胰淀素(Amylin)在机体能量代谢平衡过程中具有重要作用,通过兴奋机体饱食中枢来抑制动物摄食,Amylin的受体广泛分布于第四脑室底部最后区(AP),当受体被激活后,神经信号会通过孤束核(NTS)传至前脑,同时还可通过外侧旁核(LPBN)传至下丘脑外侧区(LHA)及下丘脑其他神经核团,Amylin信号传递必须经过NTS和LPBN,此外,Amylin也是机体发生肥胖的重要信号,肥胖动物机体Amylin的血浆浓度较正常动物显著升高,脑室注射Amylin能引起体重明显降低,而注射Amylin受体的抑制剂则使体重明显上升继而引发肥胖。Amylin是一个潜在治疗肥胖的作用靶点,本文就Amylin在调节动物摄食和能量代谢中的作用进行综述。     

瘦素（leptin）与雌性哺乳动物的繁殖活动

由脂肪细胞分泌的瘦素不仅参与食物摄入和能量平衡,而且对雌性哺乳动物的繁殖活动的调节也发挥着重要作用,其在中枢神经系统如下丘脑和垂体以及外周组织器官如卵巢、子宫和胎盘等多个层次,广泛参与对生殖活动的调节。     

电针肾旁穴对兔下丘脑雌激素受体免疫反应阳性产物的影响

研究电针肾旁穴对下丘脑内雌激素受体免疫反应阳性产物的影响及对生殖内分泌的调控。采用电针穴位法及免疫组织化学SP法。电针组兔下丘脑的视上核、室旁核、视交叉上核、室周核、腹内侧核、背侧区、小细胞核等核区有大量阳性神经元出现，染色深，突起明显，细胞形态多样，轮廓清晰；而正常组相应神经核团中阳性细胞数量较少且淡染，突起也不明显，形态单一或轮廓不清。电针肾旁穴可使家兔上述核团内雌激素受体的表达增强，从而对生殖内分泌活动进行调控。     

能量代谢调节中AMPK作用的研究进展

AMPK是一种细胞能量传感器,能准确应对代谢的动态变化和营养的过度消耗或不足。下丘脑AMPK通过作用于刺鼠相关蛋白(AgRP)和前阿片黑素细胞皮质激素(POMC)神经元来调节能量平衡和食欲。下丘脑在不同代谢状态下突触可塑性调节食欲和体重。激素的反馈机制影响AgRP和POMC神经元的突触可塑性。AMPK活性受损制约POMC神经元的主要功能是可预防肥胖。当前的研究表明,内分泌通过许多不同的代谢机制确保下丘脑AMPK从负能量平衡到能量平衡,表明了下丘脑AMPK维持基本能量平衡的重要性。文章就生长素、瘦素、胰岛素等激素对下丘脑AMPK活性的控制及对食欲和能量代谢影响的最新研究情况进行了综述。     

Recent advances in the central control of intake in ruminants.

Neuropeptide Y (NPY) is a strong stimulant of feed intake in sheep as well as in rodents. The information available indicates that it functions in vivo in the modulation of feeding within the central nervous system, more specifically, within the hypothalamus, and probably within the paraventricular nucleus. Injected NPY can override a variety of satiating factors, including those arising from normal feed intake, artificial distension of the reticulorumen, and intraruminal infusion of sodium propionate. Even so, these satiating factors are able to reduce feeding in the face of at least one dosage of exogenous NPY. Neuropeptide Y has specificity in regard to ingestive behavior in rats. It stimulates feeding and drinking but does not alter grooming behavior. It also preferentially enhances carbohydrate appetite. The possibility that specific appetites are influenced by NPY has not been investigated in ruminants. Finally, further investigations of NPY should enhance our knowledge of feed intake and energy balance regulation and its linkage with reproductive physiology.     

Central neuropeptide W has anorexigenic effect in rats

Neuropeptide W (NPW) is produced in neurons located in hypothalamus, brain stem and antral G cells and its receptors are present in the hypothalamus, in particular in the paraventricular nucleus (PVN). There are two forms of the peptide, designated as neuropeptide W‐23 (NPW23) and neuropeptide W‐30 (NPW30). Neuropeptide W is an endogenous ligand for G‐protein‐coupled receptor, GPR7 and GPR8 receptors (R), which in humans are expressed in the hypothalamus and probably involved in the control of energy homoeostasis and neuroendocrine axes. We conducted this study to investigate the effects of NPW on feeding intake and energy expenditure in Wistar rats. Systemic (icv) injection of both forms of neuropeptide W (NPW23 and NPW30) to ad libitum feeding Wistar rats decreased dark feeding and fasting‐induced feeding. One week of systemic treatment with NPW23 decreased feeding intake and weight gain during the treatment period. On the other hand, systemic treatment with antineuropeptide W antibody increased feeding intake. Moreover, systemic treatment with neuropeptide W‐23 raised body temperature and consequently thermogenesis. These results strongly suggest that neuropeptide W may play an important central role in the feeding intake and energy balance control in mammals.     

Mechanisms controlling feed intake in ruminants: a review

The purpose of this paper is to review our understanding of the involvement of central and peripheral factors in the control of feed intake in ruminants. The regulation of body weight under various states of energy need depends on an animal's ability to control feed intake to meet these needs. In the central nervous system (CNS), the ventromedial and lateral hypothalamus appear to be the areas involved in satiety and hunger, respectively; other important areas are the paraventricular nucleus and rostral brain areas. Intracerebroventricular injection of neurotransmitters, alpha- and beta-adrenergic agonists, 5-hydroxytryptamine and gamma aminobutyric acid (GABA) agonists, has stimulated feeding in ruminants; intravenous administration of benzodiazepines stimulated feed intake in sheep and cattle, possibly by increasing GABA levels in the brain. Neuropeptides of the opioid and cholecystokinin families have reciprocal hunger-stimulating and satiety-eliciting effects when administered centrally in sheep. Further, concentrations of these neuropeptides in specific areas of the hypothalamus have been shown to change with the state of hunger-satiety of sheep. In the periphery, none of the hormones associated with the pituitary, adrenal gland, pancreas or gastrointestinal tract has been shown to have significant effects on the control of feed intake. In addition, the physical properties of the ingested feed in the gastrointestinal tract, while possibly influencing the rate or pattern of feeding, do not appear to be primary factors in the control of feed intake under many feeding conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Estrogen Increases c-Fos expression in the paraventricular nucleus along with its anorexic effect in developing rats

Estrogen inhibits food intake in cycling females in a variety of species. To determine how the development of the anorexic system by estrogen is regulated, rat pups at four developmental stages, postnatal day 11 (P11)-13, P20-22, P25-27 and P29-31, and adult ovariectomized (OVX) rats received a daily subcutaneous injection of 20 μg/kg of estradiol benzoate (EB) or vehicle for three days. Food intake, body weight gain and immunohistochemical c-Fos expression in the brain were measured after each injection. EB treatment decreased both food intake and body weight gain from P27 onwards and significantly increased c-Fos expression in the parvocellular division of the paraventricular nucleus of the hypothalamus (pPVN), which is coincident with its anorexic effect in developing rats. The pattern of EB-induced c-Fos activation in other feeding-related nuclei did not coincide with its anorexic effect in developing pups. However, in adult OVX rats, EB treatment increased c-Fos expression in the nucleus tractus solitarius (NTS), the central nucleus of the amygdala (CeA), and, to a lesser degree, the ventromedial nucleus of the hypothalamus (VMH). These results suggested that the pPVN is an essential site in the brain for controlling the anorexic effect of estrogen and that the feeding system of rat begins to respond to estrogen before the onset of puberty (P25-28).     

Involvement of activin and inhibin in the regulation of food and water intake in the rat

The expression of activin and inhibin has been demonstrated in the hypothalamus, but their physiological roles in the brain remain to be elucidated. In the present study, involvement of activin and inhibin in the regulation of food and water intake was examined. Male rats were deprived of food or water for 12 and 60 hr, and mRNA levels of activin/inhibin alpha, betaA and betaB subunits in the hypothalamus were estimated by RT-PCR. Gene expression of alpha subunit transiently decreased at 12 hr of food deprivation, while it did not change during water deprivation. Food and water deprivation for 60 hr increased mRNA levels of betaA and betaB subunits, respectively. These results indicated that gene expression of each subunit was independently regulated. Injection of activin A (0.5 and 4.0 microg) into the third ventricle decreased food intake. Water intake was suppressed by 4.0 microg, but not 0.5 microg, of activin A. Intracerebroventricular injection of inhibin A (0.5 and 4.0 microg) decreased water intake in a dose dependent manner without affecting food intake, suggesting that inhibin could act independently of activin. Taken together, it is suggested that activin and inhibin take part in the central regulation of nutrient and fluid balance, though further study is needed to determine precise molecular species involved.     

Orexin A Expression in the Ovary of Dog and Cat

Orexin A and B, also known as hypocretin A and B, are hypothalamic neuropeptides arising from a precursor to the 130 amino acid, called pre–pro orexin. They are synthesized mainly in lateral and posterior hypothalamus and are involved in different functions such as regulation of food intake and energy balance. Orexins and orexin receptors were previously described also in different tissues and organs outside the brain. The aim of this study was to demonstrate by means of the immunofluorescence technique, the presence of orexin A in the ovary of cat and dog, to support the hypothesis of the role of this substance also at the level of the female genital system. The presence of orexin A in the ovary either in dog or in cat is in agreement with previous data on the presence and role of orexins in the female genital system of other species.     

Energy and protein supply for event horses during training: comparison between intake and requirements

In horses that exercise intensively (for example, event horses in training) the intake and energy requirements were compared on the basis of a diet record and estimates of energy required for exercise. Daily net energy intake over a 7 days period was on average 30% (n = 15) higher than the net energy requirement. Since the horses had a constant body weight, and thus were in energy balance, the energy intake was overestimated and/or the energy requirement was underestimated. The intake of digestible protein was 92% higher than the protein requirement. This study illustrates the problems concerning ration assessment and evaluation in practice.     

Reaction of the pituitary gland to a single GnRH administration in the dependence of energy balance in cattle in the puerperium]

After reviewing the relevant literature about the relationship of negative energy balance post partum and the onset of cyclicity the aim of this study will be described. The objective of this trial was to evaluate the influence of negative energy balance on the sensitivity of the pituitary for GnRH. Two groups of Holstein Friesian cows were randomly treated either with GnRH (Fertagyl) or a placebo. Considering the weekly calculated negative energy balance, the reaction of the pituitary was determined by analyzing LH in 16 blood samples, collected every 20 minutes starting one hour before and ending four hours after treatment. All cows treated with GnRH showed an intensive LH-surge, significantly different from the controls. These data suggest, that the sensitivity of the pituitary gland is not directly influenced by negative energy balance. The hypothalamus has the inhibiting priority over the pituitary delaying post partum cyclicity.