Fig. 1.

Basal release of prostaglandin-like material from the spleen. A rat stomach strip was bathed in splenic venous blood, except during the periods marked ‘femoral’, when it was bathed in femoral venous blood. The tracing shows the contractions of the stomach strip to prostaglandin-like material released by bradykinin (Bk, 5 μg) injected into the spleen or to direct infusions of prostaglandin E₂ (PGE₂) into the blood bathing the tissue (IBB). A reduction in tone is produced by bathing the stomach strip with femoral venous blood. Indomethacin (2 mg/kg i.v.) abolished the release of prostaglandin-like material by 5 μg of bradykinin and the contractions of the stomach strip induced by splenic rather than femoral venous blood. Note that the tone of the stomach strip in femoral blood was the same before and after indomethacin, showing that there was no prostaglandin-like material in femoral venous blood. Time 5 min; vertical scale 10 cm.