Comparison of signalling mechanisms involved in rat mesenteric microvessel contraction by noradrenaline and sphingosylphosphorylcholine

Abstract

1 We have compared the signalling mechanisms involved in the pertussis toxin-sensitive and -insensitive contraction of rat isolated mesenteric microvessels elicited by sphingosylphosphorylcholine (SPC) and noradrenaline (NA), respectively. 2 The phospholipase D inhibitor butan-1-ol (0.3%), the store-operated Ca 2+ channel inhibitor SK&F 96,365 (10 mM), the tyrosine kinase inhibitor genistein (10 mM), and the src inhibitor PP2 (10 mM) as well as the negative controls (0.3% butan-2-ol and 10 mM diadzein and PP3) had only little e ect against either agonist. 3 Inhibitors of phosphatidylinositol-3-kinase (wortmannin and LY 294,002, 10 mM each) or of mitogen-activated protein kinase kinase (PD 98,059 and U 126, 10 mM each) did not consistently attenuate NA-and SPC-induced contraction as compared to their vehicles or negative controls (LY 303,511 or U 124). 4 The phospholipase C inhibitor U 73,122 (10 mM) markedly inhibited the SPC-and NA-induced contraction (70% and 88% inhibition of the response to the highest NA and SPC concentration, respectively), whereas its negative control U 73,343 (10 mM) caused only less than 30% inhibition. 5 The rho-kinase inhibitors Y 27,632 (10 mM) and fasudil (30 mM) caused a rightward-shift of the NA concentration-response curve by 0.7 ± 0.8 log units and reduced the response to 10 mM SPC by 88% and 83%, respectively. 6 These data suggest that SPC and NA, while acting on di erent receptors coupling to di erent G-protein classes, elicit contraction of rat mesenteric microvessels by similar signalling pathways including phospholipase C and rho-kinase.

Signal Transduction Underlying Carbachol-Induced Contraction of Rat Urinary Bladder. II. Protein Kinases

“…Activation of a PI-3-kinase has also been implicated in contraction of colonic (Ibitayo et al, 1998) but not vascular smooth muscle (Altmann et al, 2003). In the present study, a high concentration of one inhibitor (wortmannin) inhibited carbachol-induced bladder contraction, whereas another one (LY 294,002) did not.…”

“…The present study has investigated the possible involvement of a number of protein kinases in carbachol-induced M 3 receptor-mediated contraction of rat urinary bladder, which have previously been implied in mediating the contraction of vascular smooth muscle (see Introduction). Recent studies have highlighted the problem that a number of prototypical kinase inhibitors can also have effects unrelated to inhibition of their cognate kinase (Davies et al, 2000;Altmann et al, 2003;El-Kholy et al, 2003). Therefore, the present study, whenever possible, has used multiple, chemically unrelated kinase inhibitors as well as negative controls, i.e., chemically related compounds that lack kinase inhibition, to minimize problems related to nonspecific inhibitor effects.…”

“…2001); and rho-associated kinase (Fukata et al, 2001;Mukai et al, 2001;Altmann et al, 2003). Therefore, we have investigated possible roles of these kinases in the carbachol-induced M 3 receptor-mediated contraction of rat bladder.…”

Signaling and Transcriptional Changes Critical for Transformation of Human Cells by Simian Virus 40 Small Tumor Antigen or Protein Phosphatase 2A B56γ Knockdown

“…Briefly, 10,000 cells were seeded in 0.3% Noble Agar and either 10 g/ml RGD or RAD peptide (Biomol, Plymouth Meeting, PA; ref. 20), 10 mol/L PP1 (21) or PP3 inhibitor (22), or 1 mol/L wortmannin. The c-srcspecific kinase inhibitor PP1 [4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo(3,4-D)pyrimidine] was obtained from Biomol and the inactive structural analogue PP3 [4-amino-7-phenylpyrazol(3,4-D)pyrimidine] was purchased from CalBiochem (San Diego, CA).…”

LY303511 (2-Piperazinyl-8-phenyl-4H-1-benzopyran-4-one) Acts via Phosphatidylinositol 3-Kinase-Independent Pathways to Inhibit Cell Proliferation via Mammalian Target of Rapamycin (mTOR)- and Non-mTOR-Dependent Mechanisms

“…Published studies use LY303511 as controls for LY294002 in experiments looking at PI3K effects in cultured cells (Ding et al, 1995;Reddy et al, 2000;Altmann et al, 2003). LY303511 differs from LY294002 by an amine substitution for the morpholino oxygen (Fig.…”