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The aim of the present study was to determine whether cobalt poisoning induces haem oxidase isoenzyme-1 (HO-1) in coronary artery smooth muscle, or accounts for any changes in coronary smooth muscle cell (SMCs) membrane ionic currents that could result from this type of heavy metal poisoning. In SMCs isolated from cobalt-treated guinea-pig coronaries, K+(More)
The electromechanical coupling in the smooth muscles of cat stomach was studied in Ca2+-free solutions containing EGTA. The experiments were carried out on circular muscle strips from the corpus of cat stomach using the single sucrose gap technique. Complete disappearance of the spontaneous electrical and contractile activity of the muscle strips was(More)
The aim of the present study was to characterize voltage-gated Ca2+ currents in smooth muscle cells freshly isolated from rat tail main artery in the presence of 5 mmol L(-1) external Ca2+. Calcium currents were identified on the basis of their voltage dependencies and sensitivity to nifedipine, Ni2+ and cinnarizine. In the majority of the cells studied, T-(More)
Circular smooth muscle strips isolated from cat gastric fundus were studied in order to understand whether the sarcoplasmic reticulum (SR) and SR Ca2+-ATPase could play a role in the regulation of the muscle tone. Cyclopiazonic acid (CPA), a specific inhibitor of SR Ca2+-ATPase, caused a significant and sustained increase in muscle tone, depending on the(More)
The effects of cyclopiazonic acid (CPA), a specific inhibitor of sarcoplasmic reticulum Ca(2+)-ATPase, on contractile activity of circular smooth muscle strips isolated from the antrum, corpus and fundus regions of the cat and guinea-pig stomach were studied. Contractile activity was recorded under isometric conditions, in organ baths. CPA, concentration(More)
In contraction studies corticotropin-releasing hormone (CRH) was found to relax ileal but not gastric and jejunal smooth muscles of the guinea-pig, precontracted with BaCl2. Under whole-cell patch-clamp conditions, CRH concentration-dependently activated Ca2+-sensitive K+ currents (IK) with ED50=20 pM at 100 nM and ED50=0. 13 pM at 500 nM intracellular Ca2+(More)
Carbon monoxide (CO) is well known as a relaxing substance in the vasculature, where it is released during the heme oxygenase (HO) reaction. Little is known about the tissue-specific targets of CO in smooth muscles. To date the functional role of CO in the coronary artery remains unclear. The expression of HO-2, the constitutive isoform of HO, but not of(More)
The relationship between inositol-1,4,5-trisphosphate-sensitive Ca2+ stores and Ca2+ entry through potential-dependent L-type Ca2+ channels was examined using whole-cell voltage-clamp technique in cells of longitudinal muscle layer of guinea-pig ileum. It was found that heparin (10(-10) mol/l) in the pipette rapidly inhibited the current through L-type Ca2+(More)
In this paper data are presented concerning some morphometrical characteristics and passive electrical properties of cell membranes from the circular layer of guinea-pig ileum (CC). The main purpose of the study has been to analyze the inward calcium current in these cells. Using the whole-cell voltage-clamp method the presence of T-like type of calcium(More)
The effects of cyclopiazonic acid and its combination with ryanodine on the inward Ca2+ current (ICa) were investigated in smooth muscle cells isolated from the circular layer of guinea-pig ileum. The ICa of these cells exhibited two components: a low-threshold, nicardipine (5 microM)-resistant, fast-inactivating component and a high-threshold,(More)