Single Hypothalamic Neurons Research Articles

ΔN-TRPV1: A Molecular Co-detector of Body Temperature and Osmotic Stress.

Thirst and antidiuretic hormone secretion occur during hyperthermia or hypertonicity to preserve body hydration. These vital responses are triggered when hypothalamic osmoregulatory neurons become depolarized by ion channels encoded by an unknown product of the transient receptor potential vanilloid-1 gene (Trpv1). Here, we show that rodent osmoregulatory neurons express a transcript of Trpv1 that mediates the selective translation of a TRPV1 variant that lacks a significant portion of the channel's amino terminus (ΔN-TRPV1). The mRNA transcript encoding this variant (Trpv1dn) is widely expressed in the brains of osmoregulating vertebrates, including the human hypothalamus. Transfection of Trpv1dn into heterologous cells induced the expression of ion channels that could be activated by either hypertonicity or by heating in the physiological range. Moreover, expression of Trpv1dn rescued the osmosensory and thermosensory responses of single hypothalamic neurons obtained from Trpv1 knockout mice. ΔN-TRPV1 is therefore a co-detector of core body temperature and fluid tonicity.

The cerebellum in feeding control: possible function and mechanism.

Accumulating anatomical, functional, and behavioral studies reveal that the cerebellum is involved in the regulation of various visceral functions including feeding control. Cerebellar lesions may induce alterations in feeding behavior and decreases in body weight. Although the exact mechanisms underlying the cerebellar regulation of food intake is still unclear, a series of studies have demonstrated that there are neural pathways directly and/or indirectly connecting the cerebellum with several important centers for feeding control, such as the hypothalamus. Electrophysiological data suggest that via the direct cerebellohypothalamic projections, the cerebellar outputs may reach, converge, and be integrated with some critical feeding signals including gastric vagal afferents, CCK, leptin, and glycemia on single hypothalamic neurons. Furthermore, recent functional imaging studies provide substantial evidences that hunger, satiation, and thirst are accompanied with a cerebellar activation. Here we describe that the cerebellum may be much more than a movement coordinator and actively participate in feeding control, i.e., it may act as an essential node linking somatic and visceral systems and help to generate an integrated and coordinated somatic-visceral response in feeding behavior.

Leptin effects on feeding-related hypothalamic and peripheral neuronal activities in normal and obese rats

We investigated the effects of leptin on central and/or peripheral feeding-related neuronal networks in Wistar male rats either normal (350–450 g) or Zucker obese (500–800 g). Low doses (1–10 pg) of leptin inhibited glucose-sensitive vagal hepatic afferent discharges and facilitated sympathetic efferent discharges to brown and white adipose tissue. Most (40–75%) neurons in the arcuate nucleus were significantly inhibited by superperfusion with leptin (0.1 nM–10 pM) under in vitro conditions. In anesthetized animals, leptin was applied electrophoretically to single hypothalamic neurons. Both glucose-sensitive neurons (GSNs) and non-GSNs in the feeding center (LHA) were significantly inhibited. Most glucoreceptor neurons in the satiety center (VMH) were significantly excited. Their depolarization was confirmed by activation of Na + and K + channels by 10 −11 M leptin using the perforate blind patch-clamp method. Although leptin excited GSNs in the parvocellular part of the paraventricular nucleus, the effects of leptin on such neuronal activity were slight or absent in Zucker obese rats. These results suggest that the feeding-suppression effects of leptin are mediated by its effects on signal transduction through both the central and the peripheral nervous systems.

Gastric vagal-evoked and greater splanchnic-evoked unitary responses in the hypothalamus

Gastric vagal and greater splanchnic nerve fibers were electrically stimulated to localize and characterize neuronal interactions in the hypothalamus of anesthetized cats. Extracellular recordings from 635 hypothalamic units were identified that responded to electrical stimulation of the left greater splanchnic nerve or gastric vagal fibers serving the proximal stomach. A total of 504 hypothalamic units in this group received input from both gastric vagal and greater splanchnic nerves. The gastric vagal-evoked hypothalamic (GVeH) and greater splanchnic-evoked hypothalamic (SeH) responses were widely distributed in the medial, paraventricular, and dorsomedial nuclei and lateral hypothalamus. The conduction velocity of the SeH response was significantly greater than the GVeH response. The latency of the SeH response showed two peaks [58 +/- 15.7 (SD) ms and 136 +/- 18.3 (SD) ms] indicating that the splanchnic input terminated on two different groups or populations of hypothalamic neurons. It also suggested that different pathways or fiber diameters in the pathway may be involved in the transmission of splanchnic input to the hypothalamus. The majority of the GVeH and SeH unitary responses were multiple spikes or short trains of action potentials. Excitatory and inhibitory responses were observed in tonically active hypothalamic units that responded to gastric vagal or greater splanchnic input. The duration of decreased excitability to gastric vagal or greater splanchnic input was significantly greater than the period of increased excitability. The condition-test paradigm was used to determine the time course of convergent gastric vagal-greater splanchnic input on single hypothalamic neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in hypothalamic neuronal function related to hormonal induction of lordosis in behaving hamsters

The hypothalamus is known to be critical for the neuroendocrine control of sexual behavior, but the neural effects of gonadal hormones on behavior-related activity of hypothalamic neurons has received little investigation. The present study examined the effects on single hypothalamic neurons of lordosis-inducing estrogen and progesterone administration to behaving golden hamsters. The lordosis-inducing action of the hormones was associated with rapidly emerging, cumulative changes in the activity level and somatosensory responsiveness of neurons throughout the hypothalamus, as well as the appearance in most neurons of lordosis-correlated firing. This functional reconfiguration of hypothalamic neuronal properties resembled, in time course and other aspects, effects of estrogen and progesterone previously observed in hamster midbrain neurons. Although the firing rates of the hypothalamic neurons were typically low, the lordosis-related activity of these neurons was compatible with a role in the control of individual episodes of lordosis as well as a state-related tendency to exhibit the lordosis response.

Glycine-gated chloride current in acutely isolated rat hypothalamic neurons.

1. Electrical and pharmacologic properties of glycine-induced currents were investigated in single hypothalamic neurons acutely isolated from young and adult rats by the use of a "concentration-clamp" technique, which allows both internal perfusion and rapid application of an external solution under single-electrode voltage-clamp. 2. The glycine-induced current reversed at the Cl- equilibrium potential (ECl), and a 10-fold decrease of extracellular Cl- with a large impermeable anion resulted in a 53 mV shift of the glycine reversal potential (EGly). 3. Glycine-induced Cl- currents (ICl) increased sigmoidally in a concentration-dependent manner with a Kd of 9 X 10(-5) M at a Hill coefficient of 1.8. Current inactivation occurred completely at all concentrations within 10 s. EGly remained unchanged during continuous application of glycine, suggesting that the inactivation process is because of desensitization. 4. The glycine-induced conductance exhibited a striking voltage dependency at membrane potentials more negative than -50 mV and reached a steady state value when hyperpolarized beyond -110 mV. 5. Both the activation and inactivation phases of glycine-induced ICl are described by double exponential (fast and slow components) functions with the concentrations used. All four time constants decreased with increasing glycine concentration. 6. The slow time constant of the current decay induced by glycine increased with depolarization and decreased with hyperpolarization, indicating that the rate of desensitization is considerably voltage dependent. The fast decay showed little voltage dependency. 7. Recovery of the glycine response after complete desensitization consisted of two components. 8. The blockade of the glycine response by strychnine and picrotoxin was noncompetitive.

Stimulation of single unit activity in the preoptic area and anterior hypothalamus, and secretion of luteinizing hormone, by ovarian steroids in ovariectomized rats with diencephalic islands.

The spontaneous activity of 454 single hypothalamic neurons was recorded in 42 chronically ovariectomized rats after severance of all neural connections with the diencephalon. In 15 of these diencephalic island preparations progesterone was administered immediately before the recording session (and just after deafferentation of the diencephalon) and oestrogen 72 h beforehand. Thirteen rats were given two injections of oestrogen at these times and the remaining 14 rats were similarly treated with equal volumes of oil. Blood samples were obtained from all rats just before each hormone or oil injection, and 4, 5, 6 and 7 h after the second one, for subsequent measurement of plasma luteinizing hormone (LH) concentration. Only the group of rats given progesterone at the time of the second injection showed a significant increase in plasma LH concentration during the recording period. There was however some individual variation and the greatest LH surge was obtained from a rat given two injections of oestrogen. For steroid-treated rats the size of the LH surge was significantly correlated (P less than 0.01) with the mean firing rate of the neurons recorded in the preoptic and anterior hypothalamic areas (p.o.--a.h.). No similar correlation could be established for p.o.--a.h. cells recorded in oil-treated rats or for cells recorded in other parts of the hypothalamus in steroid-treated rats. The mean firing rate of all p.o.--a.h. cells recorded from rats treated with oestrogen followed by progesterone was significantly higher (P less than 0.05) than in either of the other two groups of animals. The oestrogen--progesterone treatment also significantly changed the regularity of discharge of the slow firing (less than 2 Hz) p.o.--a.h. cells, but this phenomenon could not be related to any alteration in plasma LH concentration. The experiments have demonstrated for the first time that the magnitude of the steroid-stimulated LH surge in ovariectomized rats is significantly correlated with the increase in the electrical activity of p.o.--a.h. neurons.

Topographical differences in the responses of single hypothalamic neurons to limbic stimulation.

ARTICLESTopographical differences in the responses of single hypothalamic neurons to limbic stimulationJT Murphy, JJ Dreifuss, and P GloorJT Murphy, JJ Dreifuss, and P GloorPublished Online:01 Jun 1968https://doi.org/10.1152/ajplegacy.1968.214.6.1443MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByParticipation of NMDA receptors in the lateral hypothalamus in gastric erosion induced by cold-water restraintPhysiology & Behavior, Vol. 140Gastric mucosal erosion produced by NMDA microinfusions in the lateral hypothalamus: effect of selective knife cutsBehavioural Brain Research, Vol. 102, No. 1-2The lateral hypothalamic area revisited: Neuroanatomy, body weight regulation, neuroendocrinology and metabolismNeuroscience & Biobehavioral Reviews, Vol. 17, No. 2Interconnectedness of Steroid Hormone-Binding Neurons: Existence and ImplicationsNeurophysiological analysis of the development of endocrine and hypertensive reactions in prolonged emotional stressBrain Research, Vol. 344, No. 2An electrophysiological study of the neural projections from the hippocampus to the ventral pallidum and the subpallidal areas by way of the nucleus accumbensNeuroscience, Vol. 15, No. 4A [14C]2-deoxyglucose analysis of the functional neural pathways of the limbic forebrain in the rat. I. The amygdalaBrain Research Reviews, Vol. 5, No. 1Lateral septum-medial hypothalamic connections: An electrophysiological study in the ratNeuroscience, Vol. 7, No. 11Mechanism of inhibition by the amygdala in the lateral hypothalamic area of ratsBrain Research Bulletin, Vol. 8, No. 6Electrophysiological responses of neurons of the ventral tegmental area to electrical stimulation of amygdala and lateral septumNeuroscience, Vol. 6, No. 3INTRODUCTION TO PSYCHOPHYSIOLOGY OF MOTIVATION (ORGANIZATION OF THE CORTICO-LIMBIC-RETICULAR AXIS IN REGULATING HYPOTHALAMIC ACTIVITY)Influence of midbrain stimulation on the excitability of neurons in the medial hypothalamus of the ratBrain Research, Vol. 174, No. 1Amygdaloid projections to subcortical structures within the basal forebrain and brainstem in the rat and catThe Journal of Comparative Neurology, Vol. 178, No. 2Role of the Amygdaloid Complex in the Secretion of Antidiuretic Hormone and OxytocinUnitary responses of the hypothalamic nuclei to stimulation of the frontobasal neocortexNeurophysiology, Vol. 10, No. 1Comparative effects of amygdala and central gray matter of the midbrain on lateral hypothalamic unit activityNeurophysiology, Vol. 9, No. 1BibliographyProlonged medial forebrain bundle unit responses to rewarding and aversive intracranial stimuliBrain Research Bulletin, Vol. 1, No. 6Infant rats: Hypothalamic unit activityBrain Research Bulletin, Vol. 1, No. 6Unit responses in hypothalamus and mesencephalic reticular formation to acoustic stimuli and electrical stimulation of ipsi- and contralateral amygdalaPhysiology & Behavior, Vol. 17, No. 4Septal-Hypothalamic RelationshipsEvaluation of extrahypothalamic control of reproductive physiology21 June 2005Acetylcholine, an inhibitory transmitter in the rat lateral hypothalamusBrain Research Bulletin, Vol. 1, No. 1Extralimbic mediation of emotionality and social cohesiveness effectsPhysiology & Behavior, Vol. 15, No. 3The ventromedial hypothalamus and the control of avoidance behavior and aggression: Fear hypothesis versus response-suppression theory of limbic system functionBehavioral Biology, Vol. 15, No. 1Effects of electrical stimulation of the lateral habenular nucleus and lateral hypothalamus on unit activity in the upper brain stemBrain Research, Vol. 78, No. 3Effects of electrical stimulation of the lateral hypothalamus, hippocampus, amygdala and olfactory bulb on unit activity of the lateral habenular nucleus in the ratBrain Research, Vol. 77, No. 3An analysis of the effects of septal lesions on negatively reinforced behaviorBehavioral Biology, Vol. 9, No. 2The neurobiology of motivated behaviorProgress in Neurobiology, Vol. 1Influence of contingent amygdaloid stimulation on lateral hypothalamic medial forebrain bundle self-stimulationPhysiology & Behavior, Vol. 9, No. 5Effect of electrical stimulation of the septum and the lateral preoptic area on unit activity of the lateral habenular nucleus in the ratBrain Research, Vol. 43, No. 2Projections of the septum to the lateral hypothalamusExperimental Neurology, Vol. 34, No. 2Effects of Electrical Stimulation of the Amygdaloid Complex on the Ventromedial HypothalamusAmygdaloid-Hypothalamic Neurophysiological InterrelationshipsRelationships among Amygdaloid and Other Limbic Structures in Influencing Activity of Lateral Hypothalamic NeuronsThe Role of the Amygdala in Controlling Hypothalamic OutputTemporal Lobe Epilepsy: Its Possible Contribution to the Understanding of the Functional Significance of the Amygdala and of Its Interaction with Neocortical-Temporal MechanismsForebrain activation of single units in preoptic area of sunfishComparative Biochemistry and Physiology Part A: Physiology, Vol. 40, No. 3Effect of septal stimulation on lateral hypothalamic unit activity in the ratBrain Research, Vol. 32, No. 1Effects of septal stimulation on drinking elicited by electrical stimulation of the lateral hypothalamusExperimental Neurology, Vol. 32, No. 3The response of single lateral hypothalamic neurons to ventromedial nucleus and limbic stimulationPhysiology & Behavior, Vol. 6, No. 5ELECTROPHYSIOLOGICAL STUDIES OF AMYGDALO-HYPOTHALAMIC CONNECTIONSAnnals of the New York Academy of Sciences, Vol. 157, No. 2 Neural RegulaInhibitory interneurons in the ventromedial nucleus of the hypothalamusBrain Research, Vol. 9, No. 2 More from this issue > Volume 214Issue 6June 1968Pages 1443-1453 Copyright & PermissionsCopyright © 1968 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1968.214.6.1443PubMed4870150History Published online 1 June 1968 Published in print 1 June 1968 Metrics

Contrasting effects of two identified amygdaloid efferent pathways on single hypothalamic neurons.

Contrasting effects of two identified amygdaloid efferent pathways on single hypothalamic neurons.