Glial Modulation of Energy Balance: The Dorsal Vagal Complex Is No Exception

The avoidance of being overweight or obese is a daily challenge for a growing number of people. The growing proportion of people suffering from a nutritional imbalance in many parts of the world exemplifies this challenge and emphasizes the need for a better understanding of the mechanisms that regulate nutritional balance. Until recently, research on the central regulation of food intake primarily focused on neuronal signaling, with little attention paid to the role of glial cells. Over the last few decades, our understanding of glial cells has changed dramatically. These cells are increasingly regarded as important neuronal partners, contributing not just to cerebral homeostasis, but also to cerebral signaling. Our understanding of the central regulation of energy balance is part of this (r)evolution. Evidence is accumulating that glial cells play a dynamic role in the modulation of energy balance. In the present review, we summarize recent data indicating that the multifaceted glial compartment of the brainstem dorsal vagal complex (DVC) should be considered in research aimed at identifying feeding-related processes operating at this level.

Determination of the Temperature Graph of Heat Supply With Minimal Heat Losses

Heat losses by pipelines of heat supply systems are calculated for the average temperature of the heat carrier per year or for the heating period for the conditions of a qualitative method of regulating the heat load. The presence of cuts of the temperature graph, the use of other methods of central regulation, are not reflected in the regulatory documents and require special research, which determines the relevance of the work. Heat losses through thermal insulation structures of pipelines have been determined for various graphs of central regulation. Heat losses were determined for each external temperature, taking into account its duration. It is shown that the average linear annual heat losses for most of the graphs correspond to a lower external temperature than the average external temperature for the heating period. Therefore, the calculation must be performed for a higher temperature of the heat carrier than is accepted according to regulatory documents.

Optimization of the heat release regulation system

Heat supply regulation should ensure high energy efficiency of district heating systems (DHS) in general, reducing the specific indicators of heat production and release and maintaining the normalized thermal regime of the premises with any changes in outdoor temperature, insolation, infiltration and heat. Usually the processes of central regulation of DHS at heat sources and heat consumers are considered separately: not only technically but also organizationally. In this regard, the proposal for joint consideration of central and local regulation of heat supply is relevant and useful. The proposed solutions can increase the efficiency of existing DHS at the stage of transition to modern options for their implementation, in which heat control units are located at the entrance to individual apartments, and thus, the degree of regulation of DHS as close as possible to autonomous heating systems. The purpose of the study is to comprehensively consider the impact of individual stages of heat supply on the overall efficiency of DHS. The most common in domestic DHS is a method of high-quality central control of heat supply by changing the temperature of the coolant in the pipelines of thermal networks at the outlet of heat sources. However, this method has a significant disadvantage - it is inefficient regulation during the period of cutting the temperature schedule with a joint load on heating and hot water. Working during this period leads to significant overheating in premises and unproductive heat loss. Unproductive heat losses because of inadequate regulation when lowering the heat release schedule reach up to 18% of the heat potential of the fuel used. The introduction of a combined quantitative and qualitative regulation is proposed, in which, up to the cutoff temperature of the temperature schedule, the heat release is controlled by changing the temperature of the coolant, and after the cutoff, the transition to quantitative central regulation is carried out. Practical recommendations for the implementation of such regulation have been developed. Combined central regulation ensures the possibility of providing hot water supply services throughout the entire heating period, avoids hydraulic and thermal deregulation of systems and ensures optimal conditions for the operation of heat generators, reduced energy consumption and a significant increase in the overall efficiency of the DHS. Key words: heat supply, centralized systems, energy saving, efficiency, heat load regulation

The Gasotransmitter Hydrogen Sulfide and the Neuropeptide Oxytocin as Potential Mediators of Beneficial Cardiovascular Effects through Meditation after Traumatic Events

Trauma and its related psychological and somatic consequences are associated with higher cardiovascular morbidity. The regulation of both the gasotransmitter hydrogen sulfide (H2S) and the neuropeptide oxytocin (OT) have been reported to be affected during physical and psychological trauma. Both mediators are likely molecular correlates of trauma-induced cardiovascular complications, because they share parallel roles and signaling pathways in the cardiovascular system, both locally as well as on the level of central regulation and the vagus nerve. Meditation can alter the structure of specific brain regions and can have beneficial effects on cardiovascular health. This perspective article summarizes the evidence pointing toward the significance of H2S and OT signaling in meditation-mediated cardio-protection.

Prognostic criteria of psychophysiological adaptation according to visual and computer EEG analyses of employees of nuclear hazardous enterprises and industries

Introduction. The study's relevance is due to the need to improve the safety of nuclear industry enterprises and, as a consequence, to ensure a good level of psychophysiological functioning of employees. The study aims to identify the analysis of EEG indicators characterizing the FS of the central nervous system at different levels of PFA using visual and computer analysis. Materials and methods. Object - 331 archival EEGS of workers of hazardous radiation industries. The researchers determined the level of adaptation of employees using psychological, psychophysical, and physiological techniques. We conventionally recorded the EEG at rest and functional loads. In addition, scientists used a visual analysis and computer evaluation of the spectral power of EEG biopotentials in the processing. Results. With the help of visual analysis, we identified diagnostic features reflecting different levels of psychophysiological adaptation and functional activity of structural and functional formations of the central nervous system. It is possible to determine the role of structural and functional formations in forming a low level of adaptation and formulate prognostic criteria for adaptation. Researchers have identified some mechanisms of these criteria based on the evaluation results of the spectral power of EEG biopotentials. Conclusions. We identified four abnormal indicators in the EEG: "Type IV EEG", "Unstable EEG dynamics", "High index of β1 activity", "Presence of flashes of bilateral synchronous waves". These indicators indicate the presence of violations of the central regulation of the cardiovascular system and dysfunctional changes in the structures of the limbic-reticular complex. Therefore, we consider it as a criterion of a low level of PFA. The identification in the EEG of persons with a high level of PFA electroencephalographic norm indicates the absence of violations of the central regulation of the cardiovascular system and dysfunctional changes in the structures of the limbic-reticular complex. Researchers consider this a sign of a high probability of these individuals performing professional activities with a low risk of emergencies due to reduced adaptation.

Role of the Melanocortin System in the Central Regulation of Cardiovascular Functions

Increasing evidence indicates that the melanocortin system is not only a central player in energy homeostasis, food intake and glucose level regulation, but also in the modulation of cardiovascular functions, such as blood pressure and heart rate. The melanocortins, and in particular α- and γ-MSH, have been shown to exert their cardiovascular activity both at the central nervous system level and in the periphery (e.g., in the adrenal gland), binding their receptors MC3R and MC4R and influencing the activity of the sympathetic nervous system. In addition, some studies have shown that the activation of MC3R and MC4R by their endogenous ligands is able to improve the outcome of cardiovascular diseases, such as myocardial and cerebral ischemia. In this brief review, we will discuss the current knowledge of how the melanocortin system influences essential cardiovascular functions, such as blood pressure and heart rate, and its protective role in ischemic events, with a particular focus on the central regulation of such mechanisms.

Neural and Hormonal Basis of Opposite-Sex Preference by Chemosensory Signals

In mammalian reproduction, sexually active males seek female conspecifics, while estrous females try to approach males. This sex-specific response tendency is called sexual preference. In small rodents, sexual preference cues are mainly chemosensory signals, including pheromones. In this article, we review the physiological mechanisms involved in sexual preference for opposite-sex chemosensory signals in well-studied laboratory rodents, mice, rats, and hamsters of both sexes, especially an overview of peripheral sensory receptors, and hormonal and central regulation. In the hormonal regulation section, we discuss potential rodent brain bisexuality, as it includes neural substrates controlling both masculine and feminine sexual preferences, i.e., masculine preference for female odors and the opposite. In the central regulation section, we show the substantial circuit regulating sexual preference and also the influence of sexual experience that innate attractants activate in the brain reward system to establish the learned attractant. Finally, we review the regulation of sexual preference by neuropeptides, oxytocin, vasopressin, and kisspeptin. Through this review, we clarified the contradictions and deficiencies in our current knowledge on the neuroendocrine regulation of sexual preference and sought to present problems requiring further study.

Pregnancy Specific Adaptations in Leptin and Melanocortin Neuropeptides in Early Human Gestation

Introduction Pregnancy is characterized by increased appetitive drive beginning early in gestation, yet the central mechanisms underlying this adaptation are poorly understood in humans. To elucidate central mechanisms underlying appetite regulation in early pregnancy, we examine plasma and CSF leptin and AgRP as well as CSF POMC as surrogates for brain melanocortin activity. Methods Plasma leptin, Ob-Re, AgRP, and CSF leptin, POMC, and AgRP were collected from pregnant women prior to cerclage placement (16.6±1.1wks; N=24), scheduled cesarean section (39.2±0.2wks; N=24), and from non-pregnant controls (N=24), matched for age and BMI. Results Plasma leptin was 1.5 times higher in pregnancy vs. controls (P=0.01), but CSF leptin did not differ. CSF/plasma leptin percentage was lower in early pregnancy vs. controls (0.8±0.1 vs. 1.7±0.2; P<0.0001) and remained unchanged at term (0.9 ±0.1), supporting a decrease in leptin transport into CSF in pregnancy. Plasma AgRP, a peripheral biomarker of the orexigenic hypothalamic neuropeptide, was higher in early pregnancy vs. controls (95.0±7.8 vs. 67.5±5.3; P = 0.005). In early gestation, CSF AgRP did not differ from controls, but CSF POMC was 25% lower (P=0.006). In contrast, at term, CSF AgRP was 42% higher vs. controls (P=0.0001), but CSF POMC no longer differed. Overall, the CSF AgRP/POMC ratio was 1.5-fold higher in early pregnancy vs. controls, reflecting a decrease in melanocortin tone favoring appetitive drive. Conclusions Pregnancy-specific adaptions in the central regulation of energy balance occur early in human gestation and are consistent with decreased leptin transport into brain and resistance to the effects of leptin on target melanocortin neuropeptides.