Blood vessels are made up of several distinct cell types. Although it was originally thought that the tunica media of blood vessels was composed of a homogeneous population of fully differentiated smooth muscle cells, more recent data suggest the existence of multiple smooth muscle cell subpopulations in the vascular wall. One of the cell types contributing to this heterogeneity is the novel, irregularly shaped, noncontractile cell with thin processes, termed interstitial cell, found in the tunica media of both veins and arteries.
View Article and Find Full Text PDFThis work aimed to establish the lineage of cells similar to the interstitial cells of Cajal (ICC), the arterial ICC-like (AIL) cells, which have recently been described in resistance arteries, and to study their location in the artery wall. Segments of guinea-pig mesenteric arteries and single AIL cells freshly isolated from them were used. Confocal imaging of immunostained cells or segments and electron microscopy of artery segments were used to test for the presence and cellular localization of selected markers, and to localize AIL cells in intact artery segments.
View Article and Find Full Text PDFInterstitial cells of Cajal (ICCs) freshly isolated from rabbit portal vein and loaded with the Ca(2+)-sensitive indicator fluo-3 revealed rhythmical [Ca(2+)](i) changes occurring at 0.02-0.1 Hz.
View Article and Find Full Text PDFSmooth muscle cells (SMCs) contain numerous calcium release domains, grouped into regions discharging as a single unit. Laser scanning confocal microscopy, voltage clamp and immunocytochemistry of single SMCs from small mesenteric arteries of guinea-pig were used to study the localisation, function and macromolecular composition of such calcium discharge regions (CDRs). Use of the Ca(2+)-sensitive fluorescent dye fluo-3 or fluo-4 with BODIPY TR-X ryanodine (BTR), a fluorescent derivative of ryanodine, showed spontaneous Ca(2+) sparks originating from regions stained by BTR, located immediately under the plasma membrane, in the arch formed by the sarcoplasmic reticulum surrounding the nucleus.
View Article and Find Full Text PDFA voltage-gated Na+ current was characterised in freshly dissociated mouse portal vein (PV) smooth muscle myocytes. The current was found superimposed upon the relatively slow L-type Ca2+ current and was resistant to conventional Ca2+ channel blockers but was abolished by external Na+ replacement and tetrodotoxin (TTX, 1 microM). The molecular identity of the channel responsible for this conductance was determined by RT-PCR where only the transcripts for Na+ channel genes SCN7a, 8a and 9a were detected.
View Article and Find Full Text PDFArterial interstitial cells of Cajal (ICC)-like cells (AIL cells) with a multipolar, irregular, elongated shape and with numerous thin (often less than 1 microm), sometimes branching, processes with lengths up to approximately 60 microm were isolated enzymatically from 1st to 7th order branches of guinea-pig mesenteric artery. Some of the processes of AIL cells were growing (average speed approximately 0.15 microm min-1) and their growth was blocked by 10 microM latrunculin B, an inhibitor of actin polymerisation.
View Article and Find Full Text PDFReactive oxygen species (ROS) are key factors playing important roles in tissue damage of airways under different pathological conditions. Effects of ROS (superoxide anion, H2O2 and hydroxyl radical) were recorded on isometric tension of intact and epithelium denuded, not precontracted guinea pig trachea. Superoxide anion was produced by xanthine/xanthine oxidase and hydroxyl radical either by FeSO4/H2O2 or FeSO4/ascorbic acid.
View Article and Find Full Text PDFIn smooth muscle the spontaneous Ca2+ release from the sarcoplasmic reticulum (SR) occurs at preferred locations called frequent discharge sites (FDSs) giving rise to localized intracellular Ca2+ transients (Ca2+ sparks). Laser scanning confocal microscopy of fluo-3-loaded single myocytes freshly isolated from small mesenteric arteries of guinea-pig was used to investigate the action of nitric oxide (NO) donors and noradrenaline on the position and activity of FDSs and on global intracellular Ca2+ concentration ([Ca2+]i). In 8 % of cells 'microsparks', Ca2+ release events smaller in duration, spread and amplitude than Ca2+ sparks were observed.
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