Figure 10.

Ductus sphincter from term lamb. Effect of (a) BQ123 1 μM (n=7) and (b) phosphoramidon 50 μM (Phos; n=4 and 9, respectively, for the intact and endothelium-denuded vessel) on the contractile response to indomethacin 2.8 μM. Indomethacin was tested sequentially and normal Krebs was passed through the bath between applications until the contraction had fully subsided (see Methods). Where indicated, BQ123 or phosphoramidon was added to the perfusion fluid 10 min prior to starting the indomethacin test and the treatment was continued throughout the period of exposure to indomethacin. In each panel, the same tissues were studied in the absence or presence of BQ123 (or phosphoramidon). Note that in panel (b) the difference between control and treated endothelium-denuded preparations reaches significance (P<0.05) by paired t-test.