The nitrogen-containing bisphosphonates used for management of the patients with osteoporosis were reported to influence the function of renal tubular cells. However, how nitrogen-containing bisphosphates exert any effects on ion currents remains controversial. The effects of ibandronate (Iban), a nitrogen-containing bisphosphonate, on ionic channels, including two types of Ca2+-activated K+ (K...

Wade, Gregory R., Lisanne G. Laurier, Harold G. Preiksaitis, and Stephen M. Sims. Delayed rectifier and Ca21-dependent K1 currents in human esophagus: roles in regulating muscle contraction. Am. J. Physiol. 277 (Gastrointest. Liver Physiol. 40): G885–G895, 1999.—We have examined K1 channels and their function in human esophageal smooth muscle using perforated patch recording, RT-PCR to identify...

The regulation of calcium-activated K (KCa) channels by a G protein-mediated mechanism was studied. KCa channels were reconstituted in planar lipid bilayers by fusion of membrane vesicles from rat or pig myometrium. The regulatory process was studied by exploring the actions of GTP and GTP gamma S on single channel activity. KCa channels had a conductance of 260 +/- 6 pS (n = 25, +/- SE, 250/50...

In smooth muscle cells, localized intracellular Ca2+ transients, termed "Ca2+ sparks," activate several large-conductance Ca2+-activated K+ (KCa) channels, resulting in a transient KCa current. In some smooth muscle cell types, a significant proportion of Ca2+ sparks do not activate KCa channels. The goal of this study was to explore mechanisms that underlie fractional Ca2+ spark-KCa channel co...

Epoxyeicosatrienoic acids (EETs) relax various smooth muscles by increasing outward K+movement, but the molecular mode of action of EET regioisomers remains to be clarified. The effects of EETs were investigated on bovine airway smooth muscle tone and on reconstituted Ca2+-activated K+(KCa) channels. 5,6-EET and 11,12-EET induced dose-dependent relaxations of precontracted bronchial spirals. Th...

The GABAB-mediated modulation of spinal neurons in the lamprey is investigated in this study. Activation of GABAB receptors reduces calcium currents through both low- (LVA) and high-voltage activated (HVA) calcium channels, which subsequently results in the reduction of the calcium-dependent potassium (KCa) current. This in turn will reduce the peak amplitude of the afterhyperpolarization (AHP)...

Nitric oxide (NO) increases cutaneous blood flow; however, the underpinning mechanism(s) remains to be elucidated. We hypothesized that the cutaneous blood flow response during intradermal administration of sodium nitroprusside (SNP, a NO donor) is regulated by calcium-activated potassium (KCa) channels and cyclooxygenase (COX) in young adults. We also hypothesized that these contributions are ...

background and objectives: phosphlipases are a group of enzymes that breakdown phosphatidylcholine (phospholipids) molecules producing second products. these produced products have a divers role in the cell like signal transduction and digestion in humans. in this research the effect of phosphatidylcholine on the expression of plc genes of a. fumigatus was studied. the plc genes of this fungus ...

plants face many biotic and abiotic stresses at the same time during their growth under field conditions. plants responses toward combined stresses are often more complex than their responses to one type of stress in a way that the results of these responses are called as cross tolerance. this mixture of stresses activates specific models of gene expression that causes special signaling network...

background: all aerobically growing organisms suffer from exposure to oxidative stress, caused by partially reduced forms of molecular oxygen, known as reactive oxygen species (ros). these are highly reactive and capable of damaging cellular constituents such as dna, lipids and proteins. consequently, cells from many different organisms have evolved mechanisms to protect their components agains...