Despite the increasing recognition that ATP is an important extracellular excitatory mediator in the nervous system, the regulation of ATP receptors is poorly understood. Because the extracellular Zn2+ concentration is regulated in a variety of biological tissues, we studied modulation of the ATP-gated cation channel by Zn2+ in mammalian neurons using the whole-cell patch-clamp technique. In ap...

The present study was carried out to investigate the adsorption and leaching behavior of Cu2+, Zn2+ and Pb2+ by sediments collected from the western banks of three different sectors along River Nile at Aswan governorate, Egypt. The feasibility of sediments for the removal of Cu2+, Zn2+ and Pb2+ from aqueous solutions was tested under the effect of three conditions (pH, initial metal concentrati...

ORF slr0798, now designated ziaA, from Synechocystis PCC 6803 encodes a polypeptide with sequence features of heavy metal transporting P-type ATPases. Increased Zn2+ tolerance and reduced 65Zn accumulation was observed in Synechococcus PCC 7942, strain R2-PIM8(smt), containing ziaA and upstream regulatory sequences, compared with control cells. Conversely, reduced Zn2+ tolerance was observed fo...

Anabaena sp. was used to examine the toxicity of exposure to a nano-TiO2 suspension, Zn2+ solution, and mixtures of nano-TiO2 and Zn2+ suspensions. Typical chlorophyll fluorescence parameters, including effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse-amplitude modulated fluorometer. Nano-TiO2 particles exhibited no significant tox...

The mechanism of voltage-dependent substate production by external Zn2+ in batrachotoxin-modified Na+ channels from canine heart was investigated by analysis of the current-voltage behavior and single-channel kinetics of substate events. At the single-channel level the addition of external Zn2+ results in an increasing frequency of substate events with a mean duration of approximately 15-25 ms ...

Because of a huge amount of Zn2+ in secretory granules of pancreatic islet beta-cells, Zn2+ released in certain conditions might affect the function or survival of islet cells. We studied potential paracrine effects of endogenous Zn2+ on beta-cell death. Zn2+ induced insulinoma/islet cell death in a dose-dependent manner. Chelation of released endogenous Zn2+ by CaEDTA significantly decreased s...

Although Zn2+ is contained in large amounts in the synaptic terminals of hippocampal mossy fibers (MFs), its physiological role in synaptic transmission is poorly understood. By using the newly developed high-sensitivity Zn2+ indicator ZnAF-2, the spatiotemporal dynamics of Zn2+ was monitored in rat hippocampal slices. When high-frequency stimulation was delivered to the MFs, the concentration ...

The protein-tyrosine kinase Src is known to potentiate the function of NMDA receptors, which is necessary for the induction of long-term potentiation in the hippocampus. With recombinant receptors composed of NR1-1a/NR2A or NR1-1a/2B subunits, Src reduces voltage-independent inhibition by the divalent cation Zn2+. Thereby the function of recombinant NMDA receptors is potentiated by Src only whe...

Thyroid hormone status influences the Zn2+ and metallothionein levels in intestine, liver, and kidney. To evaluate the impact of thyroid hormones on Zn2+ metabolism, Zn2+ uptake studies were carried out in intestinal and renal brush-border membrane vesicles (BBMV). Steady-state Zn2+ transport in intestinal and renal cortical BBMV was increased in hyperthyroid (Hyper-T) rats and decreased in the...

The conserved active site of alkaline phosphatases (AP) contains catalytically important Zn2+ (M1 and M2) and Mg2+-sites (M3) and a fourth peripheral Ca2+ site (M4) of unknown significance. We have studied Ca2+ binding to M1-4 of tissue-nonspecific AP (TNAP), an enzyme crucial for skeletal mineralization, using recombinant TNAP and a series of M4 mutants. Ca2+ could substitute for Mg2+ at M3, w...