Mechanism of manganese dysregulation of dopamine neuronal activity

Manganese exposure produces Parkinson’s-like neurological symptoms, suggesting a selective dysregulation of dopamine transmission. It is unknown, however, how manganese accumulates in dopaminergic brain regions or how it regulates the activity of dopamine neurons. Our in vivo studies suggest manganese accumulates in dopamine neurons of the ventral tegmental area and substantia nigra via nifedipine-sensitive Ca2+ channels. Manganese produces a Ca2+ channel-mediated current which increases neurotransmitter release and rhythmic firing activity of dopamine neurons. These increases are prevented by blockade of Ca2+ channels and depend on downstream recruitment of Ca2+-activated potassium channels to the plasma membrane. These findings demonstrate the mechanism of manganese-induced dysfunction of dopamine neurons, and reveal a potential therapeutic target to attenuate manganese-induced impairment of dopamine transmission.Significance StatementManganese is a trace element critical to many physiological processes. Overexposure to manganese is an environmental risk factor for neurological disorders such as a Parkinson’s disease-like syndrome known as manganism. We found manganese dose-dependently increased the excitability of dopamine neurons, decreased the amplitude of action potentials, and narrowed action potential width. Blockade of Ca2+ channels prevented these effects as well as manganese accumulation in the mouse midbrain in vivo. Our data provide a potential mechanism for manganese-regulation of dopaminergic neurons.

Analysis of Animal Accidents along the Road of Padamara-Karangcegak in Geospatial Perspective

The occurrence of animal accidents is one of the consequences of physical environmental interaction of animal in terms of their movement from one place to another and non physical environment in the form of transportation usage by human. Accidents happened to animals can affect the structure of the food chain. It would be a matter if it occurred continuously because some species of animals that were important to the ecosystem would not exist anymore. The records of the frequency of animal accident and habitat along Jalan Padamara-Karangcegak by geospatial could be used to analyze the correlation between the dominance of animal species getting the accidents and the potential width of the habitat owned along the road. Qualitative description was used as the method of the research. It was from the primary data analysis of the distribution of accident and secondary data of the land use from Google Earth of satellite image which was then processed by Geographic Information System. The results obtained during observations from April to July 2016 showed that there was a correlation between the animal habitat and the accidents happened. The animal with a wider habitat dominated the accidents occurred than animals with no extensive habitat.

BANDGAP NARROWING IN NANO-WIRES

In this paper we consider two different geometry of quasi one-dimensional semiconductors and calculate their exchange-correlation induced bandgap renormalization (BGR) as a function of the electron-hole plasma density and quantum wire width. Based on different fabrication scheme, we define suitable external confinement potential and then leading-order GW dynamical screening approximation is used in the calculation by treating electron–electron Coulomb interaction and electron-optical phonon interaction. Using a numerical scheme, screened Coulomb potential, probability of different states, profile of charge density and the values of the renormalized gap energy are calculated and the effects of variation of confinement potential width and temperature are studied.

TEMPERATURE DEPENDENCE OF THE PHOTOSENSITIVITY OF THE NON-SELF-MAINTAINED LOW-FREQUENCY ELECTRIC DISCHARGE AND THE JOSHI EFFECT IN HALOGENS

The temperature dependence of the photosensitivity of an electric discharge with 50-cycle potentials in halogen-filled Siemens' tubes has been studied at constant gas pressure p as well as at constant mass conditions. The potential width of the photosensitive non-self-maintained region and the onset potentials of the self-maintained region of the discharge increased at constant p with the temperature T > 100 °C. In the self-maintained region of the discharge, irradiation by external light produced the familiar photoreduction of the discharge current i, viz. the negative Joshi effect, −Δi, which increased very little with T at constant p and applied potential V and reversed sign, depending on V, at 100–120 °C to the positive Joshi effect, +Δi, i.e., the photoincrease of i.Oscillographic studies of the current structure at [Formula: see text], the breakdown voltage in the dark, confirmed the co-occurrence of both +Δi and −Δi at T < 100 °C. They confirmed also that −Δi was absent at T > 100 °C. An integrating current detector which measured the resultant Δi showed that for a given p and T, +Δi increased with [Formula: see text] to a maximum; above Vm, +Δi decreased and reversed sign to −Δi as V was increased. At constant mass conditions, the Δi−V curve shifted towards the increasing potential axis by an increase in T. The potential at which +Δi was maximum and the potential at which the sign reversal of Δi occurred increased with T; the maximum magnitude of +Δi also increased with T > 100 °C.