Effect of 8-iso-prostaglandin F-2 alpha on acetylcholine release from parasympathetic nerves in guinea pig airways

8-Tso-prostaglandin F-2 alpha is present in increased amounts in airway inf lammation. g-Iso-prostaglandin F-2 alpha constricts the airways via the act ivation of thromboxane A, receptors. However, thromboxane A, receptors are also present pre-junctionally on cholinergic nerve terminals innervating gu inea pig trachea. We have demonstrated that 8-iso-prostaglandin F-2 alpha i nhibited electrical field stimulation-evoked [H-3]acetylcholine release in a concentration-dependent manner, an effect that was not inhibited by the s elective thromboxane A, receptor antagonist (4(Z)-6-[(2,4,5cis)2-(2-chlorop henyl)-4-(2-hydroxyphenyl)1,3-dioxan-5-yl]hexenoic acid) (ICI 192,605). The se data suggest that 8-iso-prostaglandin F-2 alpha inhibits acetylcholine r elease through a receptor distinct from the thromboxane A(2) receptor and p rovides evidence that isoprostanes may have a 'dual' role as both beneficia l and deleterious mediators in airway disease. (C) 2001 Published by Elsevi er Science B.V.