Interaction between glutamate and GABA systems in the integration of sympathetic outflow by the paraventricular nucleus of the hypothalamus

The paraventricular nucleus (PVN) of the hypothalamus is a central site known to modulate sympathetic outflow. Excitatory and inhibitory neurotransmitters within the PVN dictate final outflow. The goal of the present study was to examine the role of the interaction between the excitatory neurotransmitter glutamate and the inhibitory neurotransmitter GABA in the regulation of sympathetic activity. In alpha-chloralose- and urethane-anesthetized rats, microinjection of glutamate and N-methyl-D-aspartate (NMDA; 50, 100, and 200 pmol) into the PVN produced dose-dependent increases in renal sympathetic nerve activity, blood pressure, and heart rate. These responses were blocked by the NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP-5). Microinjection of bicuculline, a GABA(A) receptor antagonist, into the PVN (50, 100, and 200 pmol) also produced significant, dose-dependent increases in renal sympathetic nerve activity, blood pressure, and heart rate; AP-5 also blocked these responses. Using microdialysis and HPLC/electrochemical detection techniques, we observed that bicuculline infusion into the PVN increased glutamate release. Using an in vitro hypothalamic slice preparation, we found that bicuculline increased the frequency of glutamate-mediated excitatory postsynaptic currents in PVN-rostral ventrolateral medullary projecting neurons, supporting a GABA(A)-mediated tonic inhibition of this excitatory input into these neurons. Together, these data indicate that 1) glutamate, via NMDA receptors, excites the presympathetic neurons within the PVN and increases sympathetic outflow and 2) this glutamate excitatory input is tonically inhibited by a GABA(A)-mediated mechanism.     

Molecular phylogenetic analysis of Arenaria (Caryophyllaceae: tribe Arenarieae) and its allies inferred from nuclear DNA internal transcribed spacer and plastid DNA rps16 sequences

The systematics and phylogeny of the genus Arenaria and allied genera are unresolved. The use of morphological data has resulted in contradictory taxonomic concepts in the past due to their homoplastic nature. We present a phylogenetic analysis based on internal transcribed spacer (ITS) and rps16 sequence data of 140 (132 taxa) and 131 (120 taxa) accessions, respectively. Maximum parsimony and Bayesian analyses of each marker produced nearly congruent trees. Monophyly of Arenaria s.s. and Eremogone is confirmed here. Our results corroborate earlier results indicating that Arenaria subgenus Odontostemma is monophyletic, but outside the core group of Arenaria. Arenaria subgenus Solitaria is sister to Odontostemma and also not closely related to the latter; both of these subgenera are excluded from Arenaria and treated as distinct genera. The molecular data indicate that the ‘Arenaria s.s. clade’ consists of a few well‐supported subgroups and that the current subgeneric classification of the genus does not reflect evolutionary history. Arenaria subgenus Leiosperma is clearly monophyletic, but we reduce it to sectional level. Our molecular data show that the monotypic Arenaria subgenera Porphyrantha and Arenariastrum are nested in A. subgenus Arenaria, whereas subgenus Eremogoneastrum is included in Eremogone. None of the species‐rich sections in subgenus Arenaria is monophyletic. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 648–669.     

Die nordwestdeutsche Verbreitungsgrenze des Schwarzkehlchens und ihre ?kologische Deutung

Ohne Zusammenfassung     

A revised generic classification of the tribe Sileneae (Caryophyllaceae)

A reclassification of the tribe Sileneae compatible with molecular data is presented. The genus Eudianthe ( E. laeta and E. coeli-rosa ) is restored. Viscaria, Ixoca (= Heliosperma ), and Atocion together form a well supported monophyletic group distinct from Silene and Lychnis , and are recognized at generic level. With Agrostemma and Petrocoptis , the number of genera in the tribe sums up to eight. The new combinations Silene samojedora, Silene ajanensis, Lychnis abyssinica, Atocion asterias, Atocion compacta, Atocion lerchenfeldiana , and Atocion rupestris are made.     

Generation of thyrotropin-releasing hormone receptor 1-deficient mice as an animal model of central hypothyroidism

To provide an animal model of central hypothyroidism, mice deficient in the TRH-receptor 1 (TRH-R1) gene were generated by homologous recombination. The pituitaries of TRH-R1-/- mice are devoid of any TRH-binding capacity, demonstrating that TRH-R1 is the only receptor localized on TRH target cells of the pituitary. With the exception of some retardation in growth rate, TRH-R1-/- mice appear normal, but compared with control animals they exhibit a considerable decrease in serum T(3), T(4), and prolactin (PRL) levels but not in serum TSH levels. In situ hybridization histochemistry and real-time RT-PCR analysis revealed that in adult TRH-R1-/- animals TSHbeta-mRNA expression is not impaired whereas PRL mRNA and GH mRNA levels are considerably reduced compared with control mice. The numbers of thyrotropes, somatotropes, and lactotropes, however, are not affected by the deletion of the TRH-R1 gene. The mutant mice are fertile, and the dams nourish their pups well, indicating that TRH is not a decisive factor for suckling-induced PRL release. In situ hybridization and quantitative RT-PCR analysis, furthermore, revealed that, as in control animals, pituitary PRL-mRNA expression in TRH-R1-/- is considerably increased during lactation, albeit strongly reduced as compared with lactating control animals.     

Ectopic expression of pericentric HSATII RNA results in nuclear RNA accumulation,MeCP2 recruitment,and cell division defects

Chromosoma - Within the pericentric regions of human chromosomes reside large arrays of tandemly repeated satellite sequences. Expression of the human pericentric satellite HSATII is prevented by...     

Über die käfer- und spinnenfauna eines nordwestdeutschen Birkenbruchs

Zusammenfassung In einem Birkenbruch (Betuletum pubescentis) des nordwestdeutschen Flachlands wurde der Artenbestand an Spinnen (Araneae), Laufkäfern (Col. Carabidae) und Kurzflügelkäfern (Col. Staphylinidae) aufgenommen. Die Verteilung der Arten auf die Strauchschicht, die Krautschicht, das Torfmoos und die Streuschicht wird in Tabellen dargestellt. Die Ökologie der bezeichnenderen Arten wird kurz charakterisiert.

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Summary In the lowland of North-western Germany the animal community of a birch wood on peat-soil was investigated. This paper informs about the spiders (Araneae) and beetles (Col. Carabidae and Staphylinidae) found in the shrub layer, in the field layer, in the peat-moss, and in the surface litter. The ecology of some characteristic species is discussed.

     

Die fauna des göldenitzer hochmoores in mecklenburg

Ohne Zusammenfassung