Compounds that interact with Group II metabotropic glutamate receptors (mGluRs) have antipsychotic effects in animal models. These drugs have also shown efficacy in the treatment of schizophrenia in humans. The mechanism of action is believed to arise from a reduction of glutamatergic transmission in limbic and forebrain regions commonly associated with this disorder. Previous anatomical tracer and lesion studies have revealed that neurons of the paraventricular nucleus of the thalamus (PVT) are an important source of the glutamatergic drive to these specific regions. However, the function of Group II mGluRs in the PVT remains to be determined. Whole-cell recordings from PVT neurons reveal that activation of these receptors has two interesting effects; it reduces calcium entry through voltage-gated calcium channels and it causes neurons to hyperpolarize. These two effects may contribute to affect the excitability of PVT neurons, an action that may underlie the effectiveness of Group II mGluR-activating compounds.

Neuropeptide W-23 (NPW23) and neuropeptide W-30 (NPW30) are 23- and 30-amino acid peptides recently isolated from the porcine hypothalamus. Immunohistochemical studies using a rabbit polyclonal antiserum against the rat NPW23 peptide revealed a limited distribution in the rat brain. NPW23-immunoreactive (irNPW) cells were detected in the paraventricular nucleus (PVH), mainly in the parvocellular division, supraoptic nucleus (SO), accessory neurosecretory nuclei, dorsal and lateral hypothalamic areas, perifornical nucleus, arcuate nucleus, and anterior and posterior pituitary; whereas, irNPW fibers were noted in the PVH and SO, retrochiasmatic nucleus, dorsal and lateral hypothalamic areas, median eminence, amygdala, and posterior pituitary. The pattern of distribution of irNPW in the hypothalamus corroborates a possible role of NPW on prolactin release and feeding behavior reported by others.

Note:

The distribution of urotensin-II-immunoreactivity (irU-II) was studied in the rat brainstem and spinal cord with the use of an antiserum against the human urotensin II (U-II) peptide. A population of ventral horn neurons in the spinal cord, hypoglossal nucleus, dorsal motor nucleus of the vagus, facial motor nucleus, nucleus ambiguus, abducens nucleus and trigeminal motor nucleus exhibited irU-II of varying intensities. The number of irU-II motor neurons was higher in the lumbar segments as compared to that of cervical, thoracic and sacral segments. Double-labeling the sections with U-II- and choline acetyltransferase (ChAT)-antisera revealed that nearly all irU-II ventral horn and brainstem neurons were ChAT-positive. The result provides the first immunohistochemical evidence of the presence of irU-II in cholinergic motoneurons of the rat spinal cord and brainstem.

The principal nucleus of the bed nucleus of the stria terminalis (BNSTp) is an integral component of the mouse accessory olfactory system, and plays a key role in pheromonal processing. In males, this region is not only larger and contains more neurons than in females, but the cells are also larger. The present study examined the relationship between preference for opposite-sex odour and regional volume, cell number and cell size within the BNSTp of both male and female mice. No correlations were found between olfactory preferences and any of the three morphological BNSTp parameters. However, the olfactory preference task results were not congruent with previous research. Therefore, it remains inconclusive whether relationships exist between olfactory preference behaviour and morphology of the BNSTp.

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains x, 179 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 158-179).

The principal nucleus of the bed nucleus of the stria terminalis (BNSTp) is an integral component of the mouse accessory olfactory system, and plays a key role in pheromonal processing. In males, this region is not only larger and contains more neurons than in females, but the cells are also larger. The present study examined the relationship between preference for opposite-sex odour and regional volume, cell number and cell size within the BNSTp of both male and female mice. No correlations were found between olfactory preferences and any of the three morphological BNSTp parameters. However, the olfactory preference task results were not congruent with previous research. Therefore, it remains inconclusive whether relationships exist between olfactory preference behaviour and morphology of the BNSTp.

Adiponectin regulates feeding behavior, energy expenditure and autonomic function through the activation of two receptors present in nuclei throughout the central nervous system, however much remains unknown about the mechanisms mediating these effects. Here I investigate the actions of adiponectin in autonomic centers of the hypothalamus (the paraventricular nucleus) and brainstem (the nucleus of the solitary tract) through examining molecular, electrical, hormonal and physiological consequences of peptidergic signalling. RT-PCR and in situ hybridization experiments demonstrate the presence of AdipoR1 and AdipoR2 mRNA in the paraventricular nucleus. Investigation of the electrical consequences following receptor activation in the paraventricular nucleus indicates that magnocellular-oxytocin cells are homogeneously inhibited while magnocellular-vasopressin neurons display mixed responses. Single cell RT-PCR analysis shows oxytocin neurons express both receptors while vasopressin neurons express either both receptors or one receptor. Co-expressing oxytocin and vasopressin neurons express neither receptor and are not affected by adiponectin. Median eminence projecting corticotropin releasing hormone neurons, brainstem projecting oxytocin neurons, and thyrotropin releasing hormone neurons are all depolarized by adiponectin. Plasma adrenocorticotropin hormone concentration is increased following intracerebroventricular injections of adiponectin. I demonstrate that the nucleus of the solitary tract, the primary cardiovascular regulation site of the medulla, expresses mRNA for AdipoR1 and AdipoR2 and mediates adiponectin induced hypotension. Adiponectin has electrical effects on a majority of medial solitary tract neurons and depolarizes those expressing mRNA for the hypotensive neuropeptide Y, revealing a central mechanism to modulate blood pressure. Finally, I show that adiponectin controls paraventricular nucleus neuron excitability by either inhibiting a tetraethyl ammonium-sensitive potassium current thereby depolarizing neurons or activating a glibenclamide-sensitive voltage independent potassium current hyperpolarizing neurons. Therefore, adiponectin differentially modulates potassium current to confer its central effects. These results are the first to show the physiological and electrical actions of adiponectin on individual neurons in blood brain barrier protected central autonomic nuclei. This thesis provides a framework for how adiponectin acts centrally to coordinate whole body energy homeostasis and feeding behavior in the rat. / Thesis (Ph.D, Physiology) -- Queen's University, 2009-09-15 16:50:13.933

Techn. University, Diss., 2007--Darmstadt.

Im Jahre 2011 wurden erstmals neuronale Stammzellen (NSCs) im Nucleus Cochlearis (N.C.) der Ratte beschrieben (Rak et al. 2011). Um diese Zellen besser zu charakterisieren, war das Ziel der vorliegenden Arbeit, die NSCs des N.C. im Hinblick auf ihre Maturation und Interaktion in neuronalen Netzwerken sowie auf die Möglichkeiten nichtinvasiver Beeinflussung dieser Zellen zu untersuchen und diese mit primären Neuronen des N.C. zu vergleichen. Für die Untersuchungen waren intrazelluläre Calcium-Ionen (Ca2+) von besonderem Interesse, da diese über spannungsgesteuerte Ca2+-Kanäle (VGCCs) und deren Spontanoszillationen indirekt die Aktivität und Differenzierung der Neurone widerspiegeln könnten. Für die Analyse wurden N.C.s von P6 Ratten mikroskopisch präpariert und nach Dissoziation in Einzelzellen die NSCs für 8 Wochen in Stammzellmedium kultiviert oder direkt als primäre Neurone im Stammzellmedium ausplattiert. Zur Vorbereitung der Untersuchungen fand eine Kultivierung der jeweiligen Zellen für 4 Tage in Differenzierungsmedium statt. Anschließend wurden sie für Calcium-Imaging-Messungen mit dem Ca2+-sensitiven Fluorophor Oregon Green BAPTA-1 beladen. Zum einen wurde eine Analyse der Grundaktivitäten innerhalb der Zellareale und im neuronalen Netzwerk im Verlauf der Maturation durchgeführt. Zum anderen fand am Tag 4 der Zelldifferenzierung (DIF d4) eine Untersuchung der qualitativen und quantitativen Verteilung von VGCCs über die Zugabe der Ca2+-Kanalinhibitoren Nifedipin, ω-Conotoxin MVIIC, Kurtoxin und SNX-482 statt. In jedem Fall wurden die Zellen anschließend mit PFA fixiert und immunzytologisch untersucht. Zudem wurde eine Markierung der VGCCs mit dem Antikörper anti-Ca2+-Channel-(1 Subunit)-Pan vorgenommen. Innerhalb der Ergebnisse konnte eine Abhängigkeit der neuronalen Reifung von der Zellaktivität in Form von Ca2+-Strömen nachgewiesen werden. Hierfür zeigte sich ursächlich eine Variation im qualitativen und quantitativen Vorkommen von VGCCs und in ihrer Spontanaktivität innerhalb der Zellareale im Verlauf der neuronalen Maturation. NSCs zeigten ein ähnliches Verhalten wie primär kultivierte Neurone - sowohl bezüglich ihres Aktivitätsmusters während der Differenzierung als auch bezüglich ihrer Möglichkeit der Inhibierung, was auf eine ähnliche Expression von VGCCs hinweisen könnte. Die höchste Aktivität zeigte sich in beiden Fällen bei DIF d4. Die neurogene Nische, welche in der Literatur sowohl bei Ratten (Rak et al. 2011) als auch bei Mäusen (Volkenstein et al. 2013) im N.C. nachweisbar war, könnte somit zur Analysierung pathologischer Prozesse sowie auch zu deren Behandlung in Betracht gezogen werden. Zusammenfassend konnte in der vorliegenden Dissertation eine Charakterisierung des N.C. der Hörbahn in elektrophysiologischer und biochemischer Hinsicht erreicht werden. Die Ansätze dieser Arbeit könnten in Zukunft zu Therapieoptionen der Hörrehabilitation auf dieser Ebene beitragen. / Neural stem cells (NSCs) have been described in the cochlear nucleus (C.N.) of rats. The objective of this thesis was further characterize these cells with regard to their maturation and interaction in neural networks in comparison with primary neurons of the C.N. and the possibility of non-invasive influence by soluble factors. In this context, particular attention should be paid to the intracellular calcium ions as these could indirectly reflect the activity and differentiation of the neurons via voltage gated calcium channels (VGCCs) and their spontaneous oscillations. For analysis the C.N.s from p6 rats were microscopically prepared and after dissociation in single cells the NSCs were cultured in a neurosphere assay or plated directly as primary neurons. For calcium imaging measurements cells were loaded with the calcium sensitive fluorophore Oregon Green BAPTA-1. Spontaneous activities were analyzed within the cell areas and in neural networks during course of maturation. In addition, the qualitative and quantitative distribution of VGCCs was investigated by blocking the cells with the calcium channel inhibitors Nifedipine, ω-Conotoxin MVIIC, Kurtoxin and SNX-482. After calcium imaging analysis cells were fixed with paraformaldehyde and examined immunocytologically regarding to their status of differentiation. In addition, the VGCCs were marked by the antibody anti-calcium-channel-(1 subunit)-pan. A dependence of neural maturation on cell activity by calcium currents could be demonstrated. The reason for this was a variation in qualitative and quantitative occurrence of VGCCs and in their spontaneous activity within the cell areas in the course of neural maturation. Interestingly NSCs behaved similar to primary cultured neurons - both in their activity pattern and in their possibility of inhibition during differentiation, which indicates a similar expression of VGCCs. The highest activity in both cell types was found on day 4 of cell differentiation. In the presented thesis NSCs of the C.N. were further characterized by electrophysiological and biochemical investigations. The results could contribute to the development of new therapeutic strategies for hearing rehabilitation in the future.