Changes in metabolic activity of neurons in the anterior hypothalamus nuclei during hyperthermia, fever, and hypothermia

Differently directed changes in metabolic activity of anterior hypothalamic nuclei's neurons in rats during hyperthermia, fever, and hypothermia were revealed with histochemical methods. During hyperthermia, the activity of energy metabolism enzymes increased as well as RNA content in the neurons of supraoptic, paraventricular and median preoptic anterior hypothalamic nuclei. This is shown by an increase in the metabolic activity of neurons of these nuclei. Metabolic activity in neurons of median preoptic nuclei decreased and was not changed considerably in neurons of supraoptic and paraventricular nuclei during endotoxin-induced fever. The development of hypothermia was characterised by a decrease in metabolic activity of neurons of supraoptic, paraventricular and medium preoptic nuclei. It is supposed that differently directed metabolic activity changes in neurons of anterior hypothalamic nuclei during hyperthermia are connected with the mechanisms of body temperature regulation (median preoptic nuclei) and neurosecretory processes (supraoptic and paraventricular nuclei).     

Distribution of oxytocin and vasopressin neurons in the diencephalon of the Japanese horseshoe bat, Rhinolophus ferrumequinum. An immunohistochemical study.

The distribution of oxytocin (OXT) and vasopressin (VP) neurons in the diencephalon of the hibernating Japanese horseshoe bat, Rhinolophus ferrumequinum, was immunohistochemically investigated by the avidin-biotin complex method. Magnocellular OXT and VP neurons were localized mainly in the paraventricular nucleus and the supraoptic nucleus. In addition to these main nuclei, both kinds of magnocellular neurons were also found in the periventricular nucleus, perifornical area and lateral hypothalamic area. Extensively distributed parvocellular neurons containing only VP were observed in the rostral and middle portions of the suprachiasmatic nucleus. The size of OXT and VP magnocellular neurons was almost equal in the paraventricular and ventromedial supraoptic nuclei, whereas VP neurons were significantly larger than OXT neurons in the dorsolateral supraoptic nucleus. The OXT and VP cells in the ventral supraoptic nucleus showed a distinctive elliptical shape. Both OXT and VP fibers were distributed in the lateral habenular nucleus, stria medullaris thalami, lateral preoptic area, stria terminalis, and medial and supracapsular part of the bed nucleus of the stria terminalis. Moreover, OXT fibers were found in the substantia nigra, and VP fibers were noted in the nucleus reunions and the paraventricular nucleus of the thalamus.     

Immunocytochemical evidence for the presence of a mutant vasopressin precursor in the supraoptic nucleus of the homozygous Brattleboro rat

Summary CP-14, a tetradecapeptide from the predicted mutant vasopressin precursor in the homozygous Brattleboro rat was detected immunocytochemically in the supraoptic nucleus of homozygous Brattleboro but not normal rats. The staining was localized to the periphery of the perikarya. CP-14 immunoreactivity was not found in the neural lobes, paraventricular nuclei, accessory nuclei or suprachiasmatic nuclei of either homozygous Brattleboro or normal rats. Vasopressin immunoreactivity was found in the neural lobe and in the perinuclear region of neurons of the supraoptic, paraventricular, suprachiasmatic and accessory nuclei of normal rats. Vasopressin immunoreactivity was also found in homozygous Brattleboro rats, mainly in the ventral part of the supraoptic nucleus: densely stained solitary cells were found amongst other faintly stained perikarya. In both cell-types the staining was mainly in the periphery of the perikarya. No vasopressin immunoreactivity was detected in the paraventricular nuclei, suprachiasmatic nuclei, accessory nuclei or neural lobe of homozygous Brattleboro rats.CP-14 and vasopressin immunoreactivities were found to be co-localized; both were present in the periphery of the same perikarya of the supraoptic nuclei of homozygous Brattleboro rats. Differential staining was found with antioxytocin serum in both normal rats and homozygous Brattleboro rats: separate neurons were stained for either oxytocin or vasopressin and CP-14. Immunoreactive oxytocin was found mainly in the perinuclear region of the neurons from the supraoptic, paraventricular and accessory nuclei.     

CHANGES IN THE HYPOTHALAMO-NEUROHYPOPHYSICAL NEURO-SECRETORY MATERIALS OF RATS DURING DIFFERENT PHASES OF MORPHINE ADMINISTRATION

Abstract—

• 1 Acute morphine treatment of rats increased the concentration of neuro-secretory material in the posterior pituitary. These changes were accompanied by the presence of more neurosecretory materials in the axons of the hypothalamic supraoptic and paraventricular neurons and in the hypothalamic capillaries and sinuses. In the perikarya of the hypothalamic supraoptic and paraventricular neurons, the neurosecretory material is in a dispersed state.
• 2 Following chronic morphine treatment, neurosecretory material was almost absent from the posterior pituitary, whereas in the perikarya of the supraoptic and paraventricular neurons, congestion of neurosecretory material is observed which is accompanied by the absence of the neurosecretory material from the axons arising from the supraoptic and paraventricular nuclei and from the hypothalamic capillaries and sinuses.
• 3 During nalorphine-induced abstinence, there was sudden reappearance of the neurosecretory material in the posterior pituitary along with the appearance of neurosecretory material in the hypothalamic neurosecretory neuronal tracts, blood capillaries and sinuses together with the dispersion of the neurosecretory materials from the hypothalamic neurosecretory neurons.

     

Role of Catecholamines in Regulation of the Functional State of Vasopressinergic Cells of the Rat Hypothalamus

In in vivo and in vitro experiments there have been shown different mechanisms of regulation of hypothalamic vasopressinergic neurons, including regulation due to changes of activity level of brain catecholaminergic and NPY-ergic neurons innervating hypothalamic vasopressinergic cells. We demonstrated in in vitro experiments that dopamine and noradrenaline had no effects on vasopressin expression, but inhibited its release from cell perikarya in supraoptic and paraventricular nuclei of hypothalamus. Besides, activity of vasopressinergic neurons might probably be regulated via activation of synthesis of these neurotransmitters in vasopressinergic cells themselves in the supraoptic and paraventricular nuclei. To activate synthesis of various neurotransmitters, in our case, catecholamines and NPY, in vasopressinergic neurons, different stimuli adequate to trigger or activate synthesis of these substances are required. Synthesis of catecholamines in vasopressinergic cells of supraoptic and paraventricular nuclei was revealed after immobilization stress and adrenalectomy. NPY is synthesized in neurons of hypothalamic neurosecretory centers in norm, and its synthesis increases at disturbances of NPY-ergic innervation of vasopressinergic cells.     

Immunocytochemical demonstration of separate vasopressin-neurophysin and oxytocin-neurophysin neurons in the human hypothalamus

Summary With the use of immunocytochemistry, it was shown that both the supraoptic and paraventricular hypothalamic nuclei in humans contain at least two different neurophysins. These two human neurophysins are immunologically related to bovine neurophysin I and neurophysin II, respectively. One human neurophysin is associated with vasopressin, the other with oxytocin. Human vasopressin-neurophysin and oxytocin-neurophysin are located separately in two different types of neurons, which correspond respectively to the vasopressinergic and oxytocinergic neurons of both the supraoptic and paraventricular nuclei. The neurophysin of the human vasopressinergic suprachiasmatic neurons appears to be closely related to or identical with neurophysin of the vasopressinergic neurons of the human magnocellular hypothalamic nuclei.This investigation was supported by a grant from the Belgian Nationaal Fonds voor Geneeskundig Wetenschappelijk Onderzoek     

Topochemical aspects of nucleic-acid and protein metabolism within the neuron-neuroglia unit of the hypothalamic supraoptic nucleus

The RNA and both the total and basic protein content of individual cells were determined by cytospectrophotometry in neurons and perineuronal oligodendroglia of the hypothalamic supraoptic nucleus in rats subjected to various stresses, as well as in ground squirrels during natural hibernation. Barbiturate narcosis and deep cooling, which induced a decrease in body temperature in rats and hibernation in squirrels, caused a marked decrease of all macromolecular constituents in neurons. A similar decrease was found in the perineuronal oligodendroglia in rats, but an increase was observed in ground squirrels. After cessation of cooling, while the body temperature of the animals returned to normal, the neurons, but not the oligodendroglia, of rats showed a significant accumulation of RNA, while RNA accumulated in both neurons and perineuronal oligodendroglia in ground squirrels. Milder cooling of rats, which did not lower their body temperature, induced reciprocal changes in basic-protein content in neuronal and glial cell nuclei, with the accumulation of protein occurring initially in neurons, and subsequently in glia. When cold adaptation was accomplished, the basic protein content of neurons and glial cells returned to the control level. Four days after adrenalectomy in rats, the RNA content decreased in oligodendroglia but not in neurons of the supraoptic nucleus. This effect was completely abolished by daily injections of cortisol in the adrenalectomized animals. The data obtained indicate the existence of differences in metabolic responses to stress between neurons and glial cells of the supraoptic nucleus of the hypothalamus.     

Immunocytochemical localization of the vasopressinergic and the oxytocinergic neurons in the human hypothalamus

Summary The human hypothalamic-neurohypophysial hormone-producing nuclei were investigated with the unlabeled antibody peroxidase-antiperoxidase complex (PAP) technique at the light microscopic level. The size, shape and location of the supraoptic, paraventricular, accesssory supraoptic and suprachiasmatic nuclei were determined. It was demonstrated in the human hypothalamus, as well as in the hypothalamus of other mammals, that vasopressin and oxytocin are synthesized in separate neurons. In each of the nuclei of the magnocellular neurosecretory system, the distribution, ratios and structural features of the vasopressinergic and oxytocinergic neurons were determined. It was shown that the human suprachiasmatic nuclei contain numerous neurophysin-vasopressin-producing neurons.This investigation was supported by a grant from the Belgian Nationaal Fonds voor Geneeskundig Wetenschappelijk Onderzoek     

Immunohistochemical identification of neurons containing corticotropin-releasing factor in the rat hypothalamus

A specific rabbit anti-CRF serum and the immunoperoxidase technique were used to show that CRF-containing neurons are mainly distributed in the paraventricular and supraoptic nuclei of the rat hypothalamus. In addition, immunoreactive neurons are scattered in other hypothalamic regions. These neurons are 20--30 micrometers in diameter. From the present and previous investigations it may be concluded that the hypothalamic magnocellular nuclei, i.e., paraventricular and supraoptic, and other hypothalamic accessory nuclei, are the producing sites not only for vasopressin and oxytocin, but also for corticotropin-releasing factor.     

Distribution pattern in the human pituitary and hypothalamus of a new neuropeptide: The C-terminal glycoprotein-fragment of human pro-pressophysin (CPP)

Summary The distribution pattern of CPP-containing neurons and fibers in the human pituitary and hypothalamus was studied with a specific antiserum to human CPP and the unlabeled antibody technique. Immunoreactive CPP was found in the magnocellular neurons of the supraoptic nucleus (SON), the paraventricular nucleus (PVN) and in neurons scattered in the supraoptic hypophyseal tract. CPP-containing parvocellular neurons were found in the suprachiasmatic nucleus (SCN). The CPP-containing fibers from the magnocellular neurons formed a tract coursing through the median eminence and the pituitary stalk to the posterior lobe of the hypophysis. In contrast, no such fibers from the SCN projected to SON, PVN and the median eminence. This pattern is identical to that of vasopressin and its associated neurophysin-containing neurons and fibers and strongly supports the concept that CPP is a part of the common precursor for vasopressin and neurophysin II. The biological importance of human CPP other than being a precursor fragment remains to be elucidated.To whom requests for reprints should be addressed     

Lateral septal projections onto tubero-infundibular neurons in the hypothalamus of the guinea pig

Efferent projections of the lateral septal nucleus (LS) to the preoptic area and the hypothalamus were identified in 20 female guinea pigs after iontophoretic injection of the anterograde axonal tracer Fluoro-Ruby. Tubero-infundibular (TI) neurons of the preoptic area and the hypothalamus were retrogradely labeled after intracardiac injection of Granular Blue or Fluoro-Gold. Magnocellular neurons of the supraoptic and paraventricular nuclei were also labeled. The double labeling procedure allowed an estimation of the extent of the direct relationship between LS efferents and TI neurons. Contacts between lateral septal fibers and TI cell bodies were mainly observed at the light-microscopical level in the preoptic area. A group of labeled fibers coursing along the third ventricle established sparse connections with hypothalamic periventricular TI neurons. A few appositions was observed in the infundibular (arcuate) nucleus, suggestive of a monosynaptic regulation of TI neurons by a septo-arcuate tract. Close association with labeled magnocellular neurons was also noted at the edge of the supraoptic and paraventricular nuclei. The sparse but direct connections between LS and TI neurons may be involved in the neuroendocrine functions of the LS.     

Demonstration of a different localization of perikarya immunoreactive to oxytocin and vasopressin in the cat hypothalamus

Using immunohistochemical techniques, we demonstrated oxytocin (OT) and vasopressin (AVP) neurons in the cat hypothalamus. The OT immunoreactive neurons were found mainly in the paraventricular nucleus, supraoptic nucleus and dorsal accessory group located lateral to the fornix. In addition to these hypothalamic structures, the AVP immunoreactive neurons were observed in the suprachiasmatic nucleus, ventral accessory group located in the retrochiasmatic area and lateral accessory group, dorsal to the supraoptic nucleus caudally, and ventral to the medial part of the internal capsule rostrally. We further demonstrated a different localization of the OT and AVP immunoreactive neurons in the paraventricular and supraoptic nuclei.     

The fine structure of the hypothalamic secretory neurons of the White-crowned Sparrow,Zonotrichia leucophrys gambelii (Passeriformes: Fringillidae)

Summary The fine structures of the neurons and neuropils of the magnocellular supraoptic nucleus and the parvocellular nuclei of the rostral hypothalamus, including the suprachiasmatic and medial, lateral and periventricular preoptic nuclei, and the neuronal apparatus of the organum vasculosum laminae terminalis, have been examined in the male White-crowned Sparrow, Zonotrichia leucophrys gambelii, by correlated light and electron microscopy.The magnocellular supraoptic nucleus is characterized by large neurosecretory perikarya which contain a well developed Golgi complex and densecored granules 1,500–2,200 Å in diameter. The neuropil displays axons, dendrites and glial fibers. Some axonal profiles contain dense-cored vesicles 800–1,000 Å in diameter and clear vesicles 500 Å in diameter. Axo-somatic and axo-dendritic synapses are conspicuous in this nuclear region.The suprachiasmatic nucleus is characterized by an accumulation of small neurons with moderately developed cellular organelles and some dense-cored granules, approximately 1,000 Å in diameter. The profiles of axons within the neuropil contain dense-cored granules 800–1,000 Å in diameter and clear vesicles 500 Å in diameter.The neurons of the medial preoptic nucleus are relatively large and exhibit well developed cellular organelles and dense-cored granules 1,300 to 1,500 Å in diameter. Granular materials are formed within the Golgi complex. The medial preoptic nucleus is rich in secretory perikarya.Occasionally, neurons with granules 1,500–2,200 Å in diameter are encountered in the lateral preoptic and periventricular preoptic nuclei. They may be considered as scattered elements of the magnocellular (supraoptic and paraventricular) system.The organum vasculosum laminae terminalis consists of three layers, i.e., ependymal, internal and external zones, and exhibits a vascular arrangement similar to that of the median eminence. The perikarya of the parvocellular neurons and their axons in the internal zone contain numerous secretory granules ranging from 1,300 to 1,500 Å in diameter.This investigation was supported by Grant No. 5R040 Japan-U.S. Cooperative Science Program of the Japan Society for the Promotion of Science to Professor H. Kobayashi and Professor S.-I. Mikami, by a Scientific Research Grant No. 56019 from the Ministry of Education of Japan to S.-I. Mikami, by support from the Deutsche Forschungsgemeinschaft (Schwerpunktprogramm Biologie der Zeitmessung) to Prof. A. Oksche and by Grant No. GF 33334, U.S.-Japan Cooperative Science Program of the National Science Foundation to Prof. D.S. Farner.Herrn Professor Dr. Dres h.c. Wolfgang Bargmann zu seinem 70. Geburtstag am 27. Januar 1976 gewidmet.     

RESPIRATION AND MITOCHONDRIAL CONTENT IN SINGLE NEURONS OF THE SUPRAOPTIC NUCLEUS : A Correlative Study in Osmotic Stress

The study was undertaken to investigate the possible correlation of total volume of mitochondria per cell with the rate of succinate oxidation in isolated nerve cell bodies, after various functional stresses in the experimental animals. Significant cytological effects were found in the nerve cells of the supraoptic nucleus in rats which had been thirsting for 4–12 days or had been given 2% sodium chloride solution as a substitute for drinking water for a few weeks. Quantitation of mitochondria was done from electron micrographs. The cell volumes were calculated from sections of Epon-embedded tissue under phase-contrast microscopy. Succinate oxidation was measured on groups of 10 nerve cells with the microdiver technique. As a result of either thirst or sodium chloride load, the volume of mitochondria per nerve cell more than doubled. The rate of succinate oxidation was not changed after the rats had been thirsting but was enhanced by over 100% after they had drunk sodium chloride. A linear relationship was found for the amount of mitochondria versus respiration in the supraoptic neurons for all experimental groups except the thirsting animals. The mitochondria in the supraoptic neurons from thirsting animals were of the same size or smaller than those in controls, whereas in animals given sodium chloride solution the mitochondria were considerably enlarged. The observed effects were specific for the supraoptic nucleus.     

Ultrastructural and morphometric studies of nonsecretory neurons of the rat supraoptic nucleus

Ultrastructural and morphometric studies were made on nonsecretory and complementarily neurosecretory neurons of the rat supraoptic nucleus. 6% of perimeter of nonsecretory neuronal perikarya was covered by presynaptic endings. The value was well in agreement with that of interneurons elsewhere. The covering ratio of neurosecretory neurons was 12%. The perikarya of nonsecretory and neurosecretory neurons bear an average of 14 and 49 axon terminals, respectively. Nonsecretory neurons should be interneurons, receiving much less information than neurosecretory neurons.     

Coexistence of NADPH-diaphorase with vasopressin and oxytocin in the hypothalamic magnocellular neurosecretory nuclei of the rat

Coexistence of NADPH-diaphorase with vasopressin and oxytocin was studied in the magnocellular neurosecretory nuclei of the rat hypothalamus by use of sequential histochemical and immunocytochemical techniques in the same sections. Coexistence was found in all the nuclei examined (supraoptic, paraventricular, circular, fornical, and in some isolated neurons located in the hypothalamic area between the paraventricular and supraoptic nuclei). The ratios of neurons expressing both markers (NADPH-diaphorase and vasopressin, NADPH-diaphorase and oxytocin) in each of the nuclei were very similar. Although further studies must be carried out, the partial coexistence found in all nuclei suggests that NADPH-diaphorase is probably not related to general mechanisms involving vasopressin and oxytocin, but rather in specific functions shared by certain hypothalamic neuronal cell populations.     

Lesion of the perinuclear zone attenuates cardiac sensitivity of vasopressinergic supraoptic neurons

Discrete stretch of the caval-atrial junction decreases the activity of vasopressin-secreting neurons in the supraoptic nucleus (SON). The perinuclear zone (PNZ) of the SON is necessary for inhibition of vasopressin neurons following an increase in blood pressure. To determine whether the PNZ is necessary for cardiopulmonary regulation of vasopressin neurons, male rats received three unilateral injections of the excitotoxin ibotenic acid (n = 9) or phosphate-buffered saline vehicle (n = 10) into the PNZ. Extracellular activity of antidromically identified phasic vasopressin neurons in the ipsilateral SON was recorded. Of the 26 neurons recorded from vehicle-injected rats 26 were inhibited by an increase in blood pressure and 22 of those neurons were sensitive to caval-atrial distension. Of the neurons recorded from PNZ-lesion rats, only 12 of 29 were inhibited by an increase in blood pressure (P < 0.05), and only 11 neurons were sensitive to caval-atrial stretch (P < 0.05). Functional lesion of the PNZ significantly attenuates both arterial and cardiopulmonary baroreceptor-mediated inhibition of supraoptic vasopressin neurons, suggesting that the PNZ is a necessary component of both pathways.     

人胎儿下丘脑视上区生长抑素神经元发生学的研究

本研究采用了免疫细胞化学方法,首次系统观察了２２例９—２７周引产人胎儿下丘脑视上区的视上核和视交叉上核内的生长抑素免疫反应神经元（Ｓｏｍａｔｏｓｔａｔｉｎｉｍｍｕｎｏｒｅａｃｔｉｖｅｎｅｕｒｏｎ,简称ＳＯＭ－ＩＲ神经元）的发生、发育的形态学特征。从１６周开始,在视上核（ＳｕｐｒａｏｐｔｉｃａｌｎｕｃｌｅｕｓＳＯＮ）和交叉上核（ＳｕｐｒａｃｈｉａｓｍａｔｉｅｎｕｃｌｅｕｓＳＯＮ）内可观察到ＳＯＭ－ＩＲ神经元,在ＳＯＮ、ＳＯＭ－ＩＲ神经元数随着胎龄增加而增多,到２２周时数量最多,以后随着胎龄增加ＳＯＭ－ＩＲ神经元数出现逐渐减少现象;ＳＣＮ内的ＳＯＭ－ＩＲ神经元在１８周和２２周时出现两次高峰,研究结果提示,ＳＯＮ和ＳＣＮ内的ＳＯＭ－ＩＲ神经元在胚胎发育过程中出现消长现象,表明了ＳＯＭ－ＩＲ神经元在ＳＯＮ和ＳＣＮ内各有其独特的发育过程。