stilbenes and barium-chloride

To study the effects of resvaratrol derivatives on spontaneous HR and CF of isolated guinea pig atrium.. The dose-effect curve of resvaratrol was observed. The possible mechanism of potassium channels responsible for changes of CF and HR after administering with resvaratrol was measured.. Resvaratrol reduced the spontaneous HR and weakened the CF in a dose-dependent manner ranging from 10(-6) to 3 x 10(-4) mol x L(-1) (P < 0.05). As compared with Res group, the effects were partly blocked by Gli (P < 0.05) and TEA (P < 0.01), but not blocked by 4-AP, BaCl2, Atropine.. Resvaratrol can induce negative chronotropic action and negative (inotropic action. The mechanism(s) may relate to the opening of K(ATP) and Kc(Ca).

Topics: Animals; Barium Compounds; Cardiotonic Agents; Chlorides; Dose-Response Relationship, Drug; Female; Glyburide; Guinea Pigs; Heart Rate; In Vitro Techniques; KATP Channels; Male; Myocardial Contraction; Plants, Medicinal; Potassium Channel Blockers; Potassium Channels, Calcium-Activated; Potassium Channels, Inwardly Rectifying; Resveratrol; Stilbenes; Tetraethylammonium

The factors which influence the exocytosis of mucins are not well characterized. Since the physical properties of mucins may be affected significantly by the co-secretion of electrolytes and water, we studied the relationship between ion movement and mucin secretion in T84 cells, a human colonic adenocarcinoma cell line which has been well characterized with respect to apical chloride secretion. Secretion of mucin was assessed by immunoassay of mucin appearing in the medium within 30 min of stimulation. Cells were grown on plastic in DMEM/Ham's F12 medium and experiments were carried out at 70% confluence. Mucin secretion was stimulated by the calcium ionophore A23187, or A23187 plus vasoactive intestinal polypeptide. Stimulated mucin secretion was not affected by loop diuretics (furosemide (1 x 10(-3) M) or bumetanide (1 x 10(-4) M)), with or without the addition of ouabain (5 x 10(-5) M) and amiloride (1 x 10(-5) M), making it unlikely that transcellular chloride movements in necessary for mucin secretion. However, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; (1 x 10(-5) and 5 x 10(-5) M) and three potassium channel blockers BaCl2 (1 x 10(-3) and 5 x 10(-3) M), tetraethylammonium chloride (1 x 10(-2) M) and quinine (5 x 10(-4) M) inhibited mucin secretion. A DIDS-sensitive chloride channel or chloride/bicarbonate exchanger and a Ca2(+)-dependent potassium channel may play important roles in mucin secretion. Since plasma membranes are sparingly permeable to DIDS, the DIDS-sensitive site is likely to be on the apical plasma membrane, perhaps at an initiation locus for exocytosis.

Topics: 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; Adenocarcinoma; Amiloride; Barium; Barium Compounds; Calcimycin; Cell Line; Chlorides; Colonic Neoplasms; Furosemide; Humans; Kinetics; Mucins; Ouabain; Potassium Channels; Quinine; Stilbenes; Tetraethylammonium; Tetraethylammonium Compounds; Tumor Cells, Cultured; Vasoactive Intestinal Peptide