Our previous work reported that KCa3.1 (IKCa) channels are expressed in CA1 hippocampal pyramidal cells and contribute to the slow afterhyperpolarization that regulates spike accommodation in these cells. The current report presents data from single cell RT-PCR that further reveals mRNA in CA1 cells that corresponds to the sequence of an IKCa channel from transmembrane segments 5 through 6 incl...

During our on-going screening program designed to isolate natural compounds from marine environments, we isolated isoketochabrolic acid (IKCA) from Sargassum micracanthum, an important brown algae distributed in Jeju Island, Korea. Furthermore, we evaluated the inhibitory effects of IKCA on nitric oxide (NO) production in lipopolysaccharide (LPS)-triggered macrophages. IKCA strongly inhibited N...

Regulation of human placental syncytiotrophoblast renewal by cytotrophoblast migration, aggregation/fusion and differentiation is essential for successful pregnancy. In several tissues, these events are regulated by intermediate conductance Ca2+-activated K+ channels (IKCa), in part through their ability to regulate cell volume. We used cytotrophoblasts in primary culture to test the hypotheses...

Fioretti, Bernard, Tiziana Pietrangelo, Luigi Catacuzzeno, and Fabio Franciolini. Intermediate-conductance Ca -activated K channel is expressed in C2C12 myoblasts and is downregulated during myogenesis. Am J Physiol Cell Physiol 289: C89–C96, 2005. First published March 2, 2005; doi:10.1152/ajpcell.00369.2004.—We report here the expression in C2C12 myoblasts of the intermediateconductance Ca -a...

Methods and Results-—Coronary arterioles (80 to 150 lm in diameter) were dissected from discarded right atrial tissues of diabetic (glycosylated hemoglobin = 9.6 0.25) and nondiabetic patients (glycosylated hemoglobin 5.4 0.12) during coronary artery bypass graft surgery (n=8/group). In-vitro relaxation response of precontracted arterioles was examined in the presence of the selective SKCa/IKCa...

Rationale: Electrical conduction through gap junction channels between endothelial cells of resistance vessels is integral to blood flow control. Small and intermediate-conductance Ca -activated K channels (SKCa/IKCa) initiate electrical signals in endothelial cells, but it is unknown whether SKCa/IKCa activation alters signal transmission along the endothelium. Objective: We tested the hypothe...

The present study evaluated the role of endothelial intermediate conductance calcium-sensitive potassium channels (IKCa) in the mechanism of endothelium-derived hyperpolarizing factor (EDHF)-mediated dilations in pressurized cerebral arteries. Male rat middle cerebral arteries (MCA) were mounted in an isolated vessel chamber, pressurized (85 mmHg), and luminally perfused (100 microl/min). Arter...

Impaired endothelial function, which is dysregulated in diabetes, also precedes hypertension. We hypothesized that in Type 2 diabetes, the impaired endothelium-dependent relaxation is due to a loss of endothelium-derived hyperpolarization (EDH) that is regulated by impaired ion channel function. Zucker diabetic fatty (ZDF), Zucker heterozygote, and homozygote lean control rats were used as the ...

BACKGROUND AND PURPOSE Endothelium-derived hyperpolarizing factor responses in the rat middle cerebral artery are blocked by inhibiting IKCa channels alone, contrasting with peripheral vessels where block of both IKCa and SKCa is required. As the contribution of IKCa and SKCa to endothelium-dependent hyperpolarization differs in peripheral arteries, depending on the level of arterial constricti...