The peripheral nervous system comprises the autonomic and sensory (afferent) nervous systems. Major advances in our understanding of the autonomic and sensory transmission and function include the recognition of the phenotypic expression of a variety of transmitters and modulators that often coexist in individual neurons, the concept of co-transmission and chemical coding, the evidence for local effector functions of primary afferent nerves, and the discovery of plasticity of both the autonomic and the sensory nervous system during development, aging, diseases states, and inflammation. Co-transmission or plurichemical transmission, which indicates the release of more than one chemical messenger from the same neuron, enables autonomic and sensory neurons to exert a fine and highly regulated control of various functions such as circulation and immune response. The concept of chemical coding, in which the combination of transmitters/modulators is established, allows the identification of functional classes of neurons with their projections and targets. In addition to transmitters and modulators, autonomic and sensory neurons express multiple receptors, including G-proteincoupled and ion-gated receptors, further supporting the complexity of autonomic and sensory transmission and function. Autonomic neurons regulate the internal environment and maintain multiple homeostatic functions, and sensory neurons act as receptive structures that activate their targets in response to stimulation but also exert effector functions including the control of blood flow and vascular permeability, maintenance of mineralized tissue, and regulation of gene expression. Neurophysiology of painThe nociceptive system supports two sensory functions, pain and itch. Itch has often been regarded as a minor form of pain. Recently, it has been shown, however, that the pruritic system is supported by its own peripheral and central neuronal pathways which are closely associated, although antagonistic in some POMC processing in human melanocytes has been widely documented, and the a-MSH/MC1R/cAMP cascade has been implicated in the control of pigmentation. Only very recently, a role of b-endorphin, one cleavage product of b-LPH, has been demonstrated to influence melanocyte growth, dendricity and melanin biosynthesis via the m-opiate receptor. However, much earlier, it was shown that b-MSH, the other cleavage product of b-LPH, controls melanogenesis and melanin transfer in amphibians. To date, a specific receptor for b-MSH has not been identified. Earlier POMC processing has been found in melanosomes. Therefore, an MC1R-independent role of a-MSH was postulated and demonstrated in control of 6-tetrahydrobiopterin (6BH 4 )inhibited tyrosinase. Utilizing the depigmentation disorder vitiligo, we were now able to follow the fate of epidermal POMC processing in the presence of mM levels of hydrogen peroxide (H 2 O 2 ). In vitiligo epidermal PC2 and 7B2 protein expression is increased, whereas a-MSH, b-MSH and b-endorphin are significantly decreased. Analys...
Repolarization of canine ventricular myocardium is significantly modified by testosterone, but not oestrogen, in both genders. This effect is likely due to augmentation of expression of K(+)-channel proteins, and thus may provide protection against arrhythmias via increasing the repolarization reserve.
Morphofunctional changes in hypothalamic neurons are highly energy dependent and rely on mitochondrial metabolism. Therefore, mitochondrial adenosine triphosphate production plays a permissive role in hypothalamic regulatory events. Here, we demonstrated that in the female rat hypothalamus, mitochondrial metabolism and tissue oxygenation show an asymmetric lateralization during the estrous cycle. This asymmetry was not detected in males. The observed sidedness suggests that estrous cycle-linked hypothalamic functions in females are based on hemispheric distinction. The novel concept of hypothalamic asymmetry necessitates the revision of hypothalamic neural circuits, synaptic reorganization, and the role of hypothalamic sides in the regulation of integrated homeostatic functions.
A litter bag experiment was performed in a healthy and a die-back reed stand of Lake Ferto˝/ Neusiedler See. Mass loss, hemicellulose, cellulose, lignin, C, N, S and P concentrations of Phragmites australis leaves and culms were determined. Leaves decomposed faster than culms at both sites. After 33 months 82-90% of the leaf and 39-43% of the culm mass was lost, corresponding to a fibre loss of 82-90% and 32-35%, respectively. The N, C and S concentrations increased as decomposition proceeded, while the P concentrations decreased. The decaying coefficient model gave the best fit of the mathematical models tested (single exponential, decaying coefficient and composite exponential model). No significant differences in decomposition rates were detected between the two sites.
Contrasting to the established role of the hypothalamic agouti-related protein (AgRP) neurons in feeding regulation, the neural circuit and signaling mechanisms by which they control energy expenditure remains unclear. Here, we report that energy expenditure is regulated by a subgroup of AgRP neurons that send non-collateral projections to neurons within the dorsal lateral part of dorsal raphe nucleus (dlDRN) expressing the melanocortin 4 receptor (MC4R), which in turn innervate nearby serotonergic (5-HT) neurons. Genetic manipulations reveal a bi-directional control of energy expenditure by this circuit without affecting food intake. Fiber photometry and electrophysiological results indicate that the thermo-sensing MC4RdlDRN neurons integrate pre-synaptic AgRP signaling, thereby modulating the post-synaptic serotonergic pathway. Specifically, the MC4RdlDRN signaling elicits profound, bi-directional, regulation of body weight mainly through sympathetic outflow that reprograms mitochondrial bioenergetics within brown and beige fat while feeding remains intact. Together, we suggest that this AgRP neural circuit plays a unique role in persistent control of energy expenditure and body weight, hinting next-generation therapeutic approaches for obesity and metabolic disorders.
Oestrogen (E2) and thyroid hormones (THs) are key regulators of cerebellar development. Recent reports implicate a complex mechanism through which E2 and THs influence the expression levels of each other's receptors (ERs and TRs) to precisely mediate developmental signals and modulate signal strength. We examined the modulating effects of E2 and THs on the expression levels of their receptor mRNAs and proteins in cultured cerebellar cells obtained from 7-day-old rat pups. Cerebellar granule cell cultures were treated with either E2, THs or a combination of these hormones, and resulting receptor expression levels were determined by quantitative PCR and Western blot techniques. The results were compared to non-treated controls and to samples obtained from 14-day-old in situ cerebella. Additionally, we determined the glial effects on the regulation of ER-TR expression levels. The results show that (i) ER and TR expression depends on the combined presence of E2 and THs; (ii) glial cells mediate the hormonal regulation of neuronal ER-TR expression and (iii) loss of tissue integrity results in characteristic changes in ER-TR expression levels. These observations suggest that both E2 and THs, in adequate amounts, are required for the precise orchestration of cerebellar development and that alterations in the ratio of E2/THs may influence signalling mechanisms involved in neurodevelopment. Comparison of data from in vitro and in situ samples revealed a shift in receptor expression levels after loss of tissue integrity, suggesting that such adjusting/regenerative mechanisms may function after cerebellar tissue injury as well.
This paper describes the procedure followed for noble gas measurements for litres, millilitres and microlitres of water samples in our laboratory, including sample preparation, mass spectrometric measurement procedure, and the complete calibrations. The preparation line extracts dissolved gases from water samples of volumes of 0.2 μ l to 3 l and it separates them as noble and other chemically active gases. Our compact system handles the following measurements: (i) determination of tritium concentration of environmental water samples by the (3)He ingrowth method; (ii) noble gas measurements from surface water and groundwater; and (iii) noble gas measurements from fluid inclusions of solid geological archives (e.g. speleothems). As a result, the tritium measurements have a detection limit of 0.012 TU, and the expectation value (between 1 and 20 TU) is within 0.2 % of the real concentrations with a standard deviation of 2.4 %. The reproducibility of noble gas measurements for water samples of 20-40 ml allows us to determine solubility temperatures by an uncertainty better than 0.5 °C. Moreover, noble gas measurements for tiny water amounts (in the microlitre range) show that the results of the performed calibration measurements for most noble gas isotopes occur with a deviation of less than 2 %. Theoretically, these precisions for noble gas concentrations obtained from measurements of waters samples of a few microlitres allow us to determine noble gas temperatures by an uncertainty of less than 1 °C. Here, we present the first noble gas measurements of tiny amounts of artificial water samples prepared under laboratory conditions.
Thyroid hormones (THs) and oestrogens are crucial in the regulation of cerebellar development. TH receptors (TRs) mediate these hormone effects and are regulated by both hormone families. We reported earlier that THs and oestradiol (E 2 ) determine TR levels in cerebellar cell culture. Here we demonstrate the effects of low concentrations (10 -10 M) of the endocrine disruptor (ED) bisphenol A (BPA) on the hormonal (THs, E 2 ) regulation of TRα,β in rat cerebellar cell culture. Primary cerebellar cell cultures, glia-containing and glia-destroyed, were treated with BPA or a combination of BPA and E 2 and/or THs. Oestrogen receptor and TH receptor mRNA and protein levels were determined by real-time qPCR and Western blot techniques. The results show that BPA alone decreases, while BPA in combination with THs and/or E 2 increases TR mRNA expression. In contrast, BPA alone increased receptor protein expressions, but did not further increase them in combination with THs and/or E 2 . The modulatory effects of BPA were mediated by the glia; however, the degree of changes also depended on the specific hormone ligand used. The results signify the importance of the regulatory mechanisms interposed between transcription and translation and raise the possibility that BPA could act to influence nuclear hormone receptor levels independently of ligand-receptor interaction.Key words: Endocrine disruptors, thyroid receptor, transcription, translation, bisphenol A, rat cerebellum Thyroid hormones (THs) and oestrogens (mostly 17β-oestradiol, E 2 ) play critical roles in the regulation of central nervous system (CNS) development, in-* Corresponding author; Zsarnovszky.Attila@mkk.szie.hu; Phone: 0036 (28) 522-062/1620 (office); 0036 (30) 665-3717 (mobile); Fax: 0036 (28) 522-062
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