63 research outputs found
Enhancement Effects of Martentoxin on Glioma BK Channel and BK Channel (α+β1) Subtypes
BACKGROUND: BK channels are usually activated by membrane depolarization and cytoplasmic Ca(2+). Especially,the activity of BK channel (α+β4) can be modulated by martentoxin, a 37 residues peptide, with Ca(2+)-dependent manner. gBK channel (glioma BK channel) and BK channel (α+β1) possessed higher Ca(2+) sensitivity than other known BK channel subtypes. METHODOLOGY AND PRINCIPAL FINDINGS: The present study investigated the modulatory characteristics of martentoxin on these two BK channel subtypes by electrophysiological recordings, cell proliferation and Ca(2+) imaging. In the presence of cytoplasmic Ca(2+), martentoxin could enhance the activities of both gBK and BK channel (α+β1) subtypes in dose-dependent manner with EC(50) of 46.7 nM and 495 nM respectively, while not shift the steady-state activation of these channels. The enhancement ratio of martentoxin on gBK and BK channel (α+β1) was unrelated to the quantitative change of cytoplasmic Ca(2+) concentrations though the interaction between martentoxin and BK channel (α+β1) was accelerated under higher cytoplasmic Ca(2+). The selective BK pore blocker iberiotoxin could fully abolish the enhancement of these two BK subtypes induced by martentoxin, suggesting that the auxiliary β subunit might contribute to the docking for martentoxin. However, in the absence of cytoplasmic Ca(2+), the activity of gBK channel would be surprisingly inhibited by martentoxin while BK channel (α+β1) couldn't be affected by the toxin. CONCLUSIONS AND SIGNIFICANCE: Thus, the results shown here provide the novel evidence that martentoxin could increase the two Ca(2+)-hypersensitive BK channel subtypes activities in a new manner and indicate that β subunit of these BK channels plays a vital role in this enhancement by martentoxin
Fractalkine (CX3CL1) enhances hippocampal N-methyl-d-aspartate receptor (NMDAR) function via d-serine and adenosine receptor type A2 (A2AR) activity
P2 receptor-mediated modulation of neurotransmitter release—an update
Presynaptic nerve terminals are equipped with a number of presynaptic auto- and heteroreceptors, including ionotropic P2X and metabotropic P2Y receptors. P2 receptors serve as modulation sites of transmitter release by ATP and other nucleotides released by neuronal activity and pathological signals. A wide variety of P2X and P2Y receptors expressed at pre- and postsynaptic sites as well as in glial cells are involved directly or indirectly in the modulation of neurotransmitter release. Nucleotides are released from synaptic and nonsynaptic sites throughout the nervous system and might reach concentrations high enough to activate these receptors. By providing a fine-tuning mechanism these receptors also offer attractive sites for pharmacotherapy in nervous system diseases. Here we review the rapidly emerging data on the modulation of transmitter release by facilitatory and inhibitory P2 receptors and the receptor subtypes involved in these interactions
Differential manifestations of prepubescent, pubescent and postpubescent pediatric patients with systemic lupus erythematosus: A retrospective study of 96 Chinese children and adolescents
Evidence for the Migration of B-cells Spontaneously Secreting Monomeric Iga and Iga From Peripheral Compartments Into Inflamed Intestine in Inflammatory Bowel-disease
An Increased Percentage of Monomeric Iga and Iga Subclass-1 (iga1) Is Present in the Iga Spontaneously Secreted By Isolated Intestinal Mononuclear-cells From Inflammatory Bowel-disease Patients
Altered Patterns of Secretion of Monomeric Iga and Iga Subclass-1 By Intestinal Mononuclear-cells in Inflammatory Bowel-disease
Electroweak Parity-Violating Energy Shifts of Amino Acids: The “Conformation Problem”
Endothelium-derived relaxing factor release on activation of NMDA receptors suggests role as intercellular messenger in the brain
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