Vagotomy: effect on electrically elicited eating and self-stimulation in the lateral hypothalamus

A subdiaphragmatic vagotomy markedly inhibits eating and self-stimulation produced in rats by lateral hypothalamic stimulation. The stomach is known to be affected by hypothalamic stimulation via the vagus, and afferents from the stomach can influence the hypothalamus via the same nerve. Consequently, this result suggests that eating and self-stimulation may be partly controlled by hypothalamic influences on the stomach which, in turn, affects hypothalamic sensitivity.     

Heart rate: differential effects of hypothalamic and septal self-stimulation

Heart rate in rats was recorded during self-stimulation with electrodes permanently implanted in both the hypothalamus and the septal region. Acceleration was observed during stimulation of the hypothalamus, and deceleration during stimulation of the septal region. In both areas self-stimulation reduced variability in heart rate.     

Estrous cycle in the rat: effects on self-stimulation behavior

The performance of female rats, in pressing a bar for electrical stimulation of the hypothalamus, changes during the estrous cycle. Highest barpressing rates accompany the appearance of vaginal cornification. This increase is not an artifact of increased spontaneous activity at estrus, although the factors underlying these changes in activity may also mediate the changes in self-stimulation behavior.     

Brain histamine: rapid apparent turnover altered by restraint and cold stress

Histamine content of rat brain was lowered quickly by inhibitors of histidine decarboxylase, suggesting that a portion of brain histamine turns over rapidly. Restraint and exposure to cold also reduced brain histamine levels and markedly augmented its formation in the hypothalamus.     

Hyperphagia in rats with cuts between the ventromedial and lateral hypothalamus

Bilateral cuts between the ventromedial and lateral hypothalamus in female rats consistently produced hyperphagia. Hyperphagia occurred slightly less reliably when one of the cuts entered the ventromedial hypothalamus and only infrequently if one entered the lateral hypothalamus. The results are consistent with other evidence that suggests that fibers originating medially stop eating by inhibiting cells in the lateral hypothalamus.     

能量条件对鸭下丘脑5-羟色胺样神经元的影响

 选用来自同一父母代的1日龄健康樱桃谷鸭60羽，饲喂1周后，随机分为2组：高能组和低能组，分别饲喂高能和低能日粮。饲喂4周后，处理动物：灌流固定，取全脑后固定4 h，入8%蔗糖溶液中4℃保存。制作石蜡切片，采用免疫组化链霉亲和素-生物素-过氧化物酶复合物法( Streptavidin -biotin-peroxidase complex method，SABC)进行染色，并用图像分析系统作半定量分析。结果显示：高能组室旁核（17.73±1.41个/19.46×103μm2）及腹内侧核（15.80±1.71个/ 19.46×103μm2）有大量的阳性胞体；低能组外侧区（11.25±1.53个/19.46×103μm2）也有大量的阳性胞体，而室旁核没有。上述研究结果表明，下丘脑5-羟色胺样神经元参与摄食和能量代谢的调节。     

Lateral hypothalamic control of killing: evidence for a cholinoceptive mechanism

In rats that would not ordinarily kill mice, lateral hypothalamic injection of crystalline carbachol, a cholinomimetic, elicited killing. Norepinephrine, amphetamine, serotonin, and sodium salts were ineffective at the same site. Carbachol was ineffective when injected into the medial, dorsal, or ventral hypothalamus. As additional evidence for a cholinoceptive mechanism, neostigmine elicited killing, and, in spontaneous killers, methyl atropine blocked it. The results indicate that the lateral hypothalamus contains a cholinoceptive component of an innate system that activates killing, and anticholinergic treatment can be used as a means of suppressing killing.     

Relationship between feeding and satiation centers of the hypothalamus

Electrodes were implanted in the hypothalamus of five goats in which an alimentary instrumental conditioned reflex had been previously established. Electrical stimulation of the ventromedial hypothalamus inhibited the conditioned movements and food intake in hungry goats. This also occurred in those satiated goats in which eating and conditioned movements were elicited by stimulation of the lateral hypothalamic area. Withdrawal of the stimulation of the medial hypothalamus evoked a short aftereffect in the form of a recovery or increase in the trained movements and food intake.     

猪下丘脑开胃素 A的分布定位

用免疫组织化学方法研究了5头苏钟猪下丘脑内开胃素(orexin)A的分布。结果表明，在猪下丘脑内，开胃素A免疫阳性神经元分布于下丘脑的视前内侧区、室周核、室旁核、视上核、背内侧核、穹隆周核、乳头体核、前区、外侧区和后区等部位，以下丘脑外侧区、乳头体核和视上核出现的免疫阳性神经元最多，以室周核的最少。这一结果与在其他动物上获得的基本相似。     

Behavioral effects of progesterone associated with rapid modulation of oxytocin receptors

The ventromedial nuclei of the hypothalamus (VMN) are important for the control of feminine mating behavior, and hormone action within these nuclei has been causally related to behavior. Estradiol induces receptors for oxytocin in the VMN and in the area lateral to these nuclei over the course of 1 to 2 days, and progesterone causes, within 30 minutes of its application, a further increase in receptor binding and an expansion of the area covered by these receptors lateral to the VMN. The rapid progesterone effect appears to be a direct and specific effect of this steroid on the receptor or membrane, because it was produced in vitro as well as in vivo and was not mimicked by a variety of other steroids. The effect of progesterone occurred in the posterior part of the VMN, where oxytocin infusion facilitated feminine mating behavior; it did not take place in the anterior part of the VMN, where oxytocin infusion had no effect on mating behavior.     

Olfactory input to the hypothalamus: electrophysiological evidence

Electrical stimulation of the rat's olfactory bulb or lateral olfactory tract elicited unit discharges in the region of the medial forebrain bundle of the lateral hypothalamus, with latencies of 4 to 25 milliseconds. Unit responses in this area were driven by odors in preparations that were paralyzed to prevent breathing artifacts.     

外源性神经激肽B对雌性大鼠生殖轴GnRH和Kisspeptin表达的影响

为研究外源性神经激肽B(NKB)对雌性大鼠下丘脑促性腺激素释放激素(GnRH)和下丘脑-垂体-卵巢轴(HPOA)GnRH和Kisspeptin表达的影响,将40只60d的Sprague-Dawley(SD)雌性大鼠随机分为试验组和对照组,侧脑室分别注射NKB溶液和等体积生理盐水,20min后处死采集样品。采用免疫荧光技术分析各组织的GnRH和Kisspeptin蛋白表达,实时荧光定量PCR(RT-qPCR)分析GnRH和Kiss1mRNA的表达量变化。结果显示,与对照组相比,试验组下丘脑GnRH mRNA显著增加(P0.05),Kiss1 mRNA表达量显著降低(P0.05);试验组下丘脑视前区(POA)中GnRH阳性细胞数量显著增加(P0.05),弓状核(ARC)和正中隆起(ME)中GnRH阳性细胞数量增加(P0.05),但下丘脑ARC,POA,室旁核(PVN)和前腹侧室旁核(AVPV)中Kisspeptin阳性细胞数显著减少(P0.05);且NKB抑制腺垂体中Kisspeptin的表达(P0.05),但不影响卵巢中Kisspeptin的表达。综上,NKB通过调节HPOA Kisspeptin和下丘脑GnRH的表达来调控雌性大鼠的生殖。     

The Effect of Energy on Serotonin-Like Neurons in Duck Hypothalamus

In the present study, immunohistochemical method (SABC method) was used to examine the distribution of serotonin-like neurons in hypothalamus of Cherry Valley ducks bred with high energy diet and low energy diet respectively. All films were analysed by using a computer-assisted image analysis system. In high energy group, labelled neurons are widely distributed in paraventricular nucleus(PVN, 17.73± 1.41 neurons/19.46× 103 μm2) and ventromedial hypothalamus (VMH,15.8±1.71 neurons/19.46×103 μm2); in low energy group, labelled ceils are widely distributed in lateral hypothalamus (LH,11.25±1.53 neurons/19.46×103 μm2), yet there is no positive neuron in PVN. These results indicate that serotonin-like neurons in hypothalamus are involved in the regulation of food intake and energy metabolism.     

Self-stimulation alters human sensory brain responses

Human electrocortical potentials evoked by self-administered auditory and visual stimuli manifest much smaller amplitude and faster poststimulus timing than do average brain responses evoked by identical machine-delivered stimuli. Auditory evoked potentials show this "self-stimulation effect" to a greater degree than do visual responses. For visual evoked potentials, the effect appears greater at the vertex association area than over the occipital cortex. Individual differences in the magnitude of the "self-stimutlation effect" relate to level of intelligence.     

Norepinephrine: reversal of anorexia in rats with lateral hypothalamic damage

Injection of norepinephrine in the lateral ventricles of rats recovering from lateral hypothalamic anorexia caused immediate feeding and, frequently, overeating. Intraventricular administration of the alpha-noradrenergic blocker, phentolamine, suppressed feeding in both normal rats and rats that had recovered from lateral hypothalamic lesions. Feeding is reinforced by ascending medial forebrain bundle fibers that form alpha-noradrenergic synapses in the hypothalamus and forebrain. Damage to these fibers suppresses feeding by reducing noradrenergic transmission and, hence, the rewarding value of food. Recovery of feeding after hypothalamic lesions coincides with the recovery of noradrenergic reward function.     

Analgesia from electrical stimulation in the brainstem of the rat

Stimulation at several mesencephalic and diencephalic sites abolished responsiveness to intense pain in rats while leaving responsiveness to other sensory modes relatively unaffected. The peripheral field of analgesia was usually restricted to one-half or to one quadrant of the body, and painful stimuli applied outside this field elicited a normal reaction. Analgesia outlasted stimulation by up to 5 minutes. Most electrode placements that produced analgesia also supported self-stimulation.One placement supported self-stimulation only in the presence of pain.     

Neuron function inferred from behavioral and electrophysiological extimates of refractory period

The refrcactory period of neurons mediating an electrically elicited behavior (self-stimulation) was estimated by varying the intrapair pulse separation in a stimulating train made up of pulse pairs and measuring the intensity of the elicited behavior. Two neuronal systems with different refractory periods were indicated. Single-unit recording in acute preparations stimulated through self-stimulation electrodes revealed primarily two classes of units. Each class gave refractory period estimates characteristic of one of the behaviorally indicated systems. The experiments illustrate a technique for establishing functional relations between single units in the brain and gross behavior.     

Eating or drinking elicited by direct adrenergic or cholinergic stimulation of hypothalamus

A double cannula system, allowing repeated stimulation of central structures with crystalline chemicals, was developed. This technique was employed to study the effects of adrenergic and cholinergic stimulation of the lateral hypothalamus of rats. Drug-specific effects on the feeding and drinking mechanisms, respectively, were observed.     

Glucoreceptors controlling feeding and blood glucose: location in the hindbrain

Microinfusion of 5-thioglucose into either the lateral or fourth cerebral ventricle caused increased feeding and hyperglycemia in rats when the cerebral aqueduct was unobstructed. If the aqueduct was obstructed and 5-thioglucose was infused into the fourth ventricle, increased feeding and hyperglycemia persisted, whereas feeding and hyperglycemia in response to lateral ventricle infusion were abolished. Drinking in response to infusion of angiotensin II into the lateral ventricle was not diminished by aqueduct obstruction. These results indicate that glucoreceptors that mediate feeding and hyperglycemia in response to cerebral glucoprivation are located in the caudal hindbrain and not in the hypothalamus where they have previously been sought.     

Localization of the adrenergic feeding system in the rat diencephalon

Injection of 6 micrograms of aqueous norepinephrine elicits eating only when it takes place at sites within a limited region of the rat brain. The distribution of effective sites coincides with that of systems connected to an extrahypothalamic pathway between the limbic forebrain and tegmental motor systems. It does not correspond to those parts of the lateral hypothalamus thought to control normal feeding.