No abstract

1Endothelin-1 (ET-1) binding site densities and constrictor activities were compared in airway smooth muscle preparations of human, guinea-pig, rat and mouse. 2 The mean contractile response to 0.3 pM ET-1 (measured as the % maximum response to 10puM carbachol, % C,.., + s.e.mean) and the mean concentration of ET-1 producing 30% C,.,. (95% confidence limits) were respectively; 85.9 + 5.4% and 3.4nM (2.4-5.0) for mouse trachea (n = 11), 88.8 + 4.7% and 18.2nM (11.2-25.2) for rat trachea (n = 6), 71.0 + 7.1% and 35.2 nm (5.4-231) for human bronchus (n = 3), and 32.3 + 3.0% and 241 nm (125-460) for guinea-pig trachea (n = 6). .5 amol mm-2) > mouse trachea (28.7 + 2.6 amol mm 2) > guinea-pig trachea (8.3 + 1.8 amol mm-2). 5 A positive relationship between [125I]-ET-1 binding site density and ET-1 constrictor activity was observed in airway smooth muscle preparations from rat, human and guinea-pig. The greater sensitivity of mouse trachea to the constrictor actions of ET-1 was not dependent on the release of cyclo-oxygenaseor epithelium-derived constrictor substances, but may have been due to an inter-species difference in the receptor-effector system for ET-1.

The importance of story‐telling in organizational life has often been overlooked in contemporary organizational and leadership literature. Throughout history, leaders ‐ political and religious ‐ have used story‐telling as a powerful motivational tool, particularly during times of uncertainty, change and upheaval or in response to crises. This article looks at the role of story‐telling as an integral part of the human experience and at its applications in modern organizational life. The article concludes by suggesting that the art of story‐telling is still, despite recent advances in communication technologies, an essential managerial skill ‐ particularly for leaders of organizations.

1 The effects of endothelin-1 (ET-1) and of the muscarinic cholinoceptor agonist, carbachol, on 4 ET-1 also produced concentration-dependent contractions of epithelium-denuded rat tracheal ring preparations. The mean concentration of ET-1 producing 50% of the maximum contractile response to carbachol (EC50) was 31 nm (95% confidence limits, 20-49 nM, n = 12). The presence of an intact tracheal epithelium, indomethacin (5puM), WEB 2086 (10pM) and phosphoramidon (10puM) had no significant effect on the mean EC50 for ET-1-induced contraction (n = 5). In contrast, NDGA (10pM) inhibited ET-1-induced contractions (4.0 fold increase in mean EC50, P < 0.001, n = 5). However, this effect of NDGA did not appear to be related to inhibition of leukotriene synthesis via lipoxygenase since the leukotriene antagonist SKF 104353 did not affect ET-1-induced contractions (n = 5) and moreover, leukotriene C4 and leukotriene D4 did not contract rat isolated tracheal smooth muscle preparations (n = 4). 5 The threshold concentrations of ET-1 that produced increases in smooth muscle contraction and [3H]-InsPs accumulation were similar, although the EC50 for [3H]-InsP accumulation was 2.9 fold greater than that for smooth muscle contraction. For carbachol, the EC50 for [3H]-InsP accumulation (mean ECQO = 5.0pM, 1.2-21 pM, n = 4) was 25 fold greater than that for smooth muscle contraction (mean EC50 = 0.20UM, 0.17-0.24jpM, n = 12).6 It seems likely that ET-1 has a direct effect on InsP generation in rat tracheal smooth muscle and that this is largely responsible for the spasmogenic actions of this peptide.