Vasopressin‐stimulated [³H]‐inositol phosphate and [³H]‐phosphatidylbutanol accumulation in A10 vascular smooth muscle cells

Abstract

1 The characteristics of vasopressin-stimulated phosphatidylinositol 4,5 bisphosphate (PtdIns(4,5)P2) and phosphatidylcholine (PtdCh)

Regulation by hypoxia of endothelin‐1‐stimulated phospholipase D activity in sheep pulmonary artery cultured smooth muscle cells

“…This finding is consistent with results obtained in vasopressin-stimulated AlO smooth muscle cells and in bombesin-stimulated Swiss 3T3 fibroblasts (Plevin et al, 1992;Plevin & Wakelam 1992;Briscoe et al, 1993). We also observed that the response was dependent upon prior PKC activation since incubation with the PKC inhibitor, Ro-318220, abolished both TPA and agonist-stimulated PLD activity.…”

“…Following scraping and transfer to plastic vials, the inositol polyphosphates were extracted by the addition of chloroform (0.5 ml) and methanol (0.5 ml) to give a final ratio of 2:1. The phases were then split by the addition of chlorofom/methanol/water to a final ratio of 1:1:0.8 and a sample of the aqueous phase was assayed for inositol phosphates by ion anion exchange chromatography on Dowex formate columns as previously described (Plevin et al, 1992 period the reaction was terminated by the addition of 100 ttl of 25% (w/v) trichloroacetic acid in 2 M acetic acid. After 10 min on ice, the cells were scraped and the extracts transferred to microfuge tubes and spun for 5 min for 14,000 g at 4°C.…”

“…An intracellular signalling pathway which may also play a role in the regulation of smooth muscle cell growth and contraction involves the hydrolysis of phosphatidylcholine by phospholipase D (PLD) (Cook & Wakelam 1989;Billah & Anthes 1990;MacNulty et al, 1990;Plevin et al, 1992). The product from this reaction, phosphatidic acid, may have second messenger roles in agonist-stimulated smooth muscle contraction (Ohanian et al, 1990).…”

Formation of biologically active autacoids is regulated by calcium influx in endothelial cells.

“…10 The inhibitor of receptor-operated calcium influx SK&F 96365 is active in a variety of mammalian cells including human platelets and neutrophils, 16 eosinophils, 23 smooth muscle cells, 26 neuronal cells, 27 and ECs of different species. 16 - 28 Our results in ECs demonstrate that SK&F 96365 blocks calcium entry when administered both before and after stimulation with histamine, which suggests that the compound does not interfere with the binding of histamine with its receptor.…”

Oxytocin receptors expressed and coupled to Ca2+ signalling in a human vascular smooth muscle cell line

“…In the rat, vasopressin-induced contraction of vascular smooth muscle cells is found to be mediated by VIA receptor (Plevin et al, 1992;Thibonnier et al, 1991), and the same receptor subtype is thought to be present in human vascular smooth muscle. In the present study, we have examined the vasopressin/oxytocin receptor subtype expressed in a human vascular smooth muscle cell line (HVSMC) by comparing binding characteristics of [3H]-AVP with that in A10 rat vascular smooth muscle cells (VSMC).…”