Abstract: The effects of anisodamine (654-2) on acetylcholine (Ach) and norepinephrine(NE)-induced prostaglandin(PG) release, measured by RIA, were investigated. The major products released by rabbit iris were PGE₂ and 6-keto-PGF_1α and the release of PGs increased with time of incubation. PGE₂ output was 0.43μg/g tissue after 30 min of incubation and 2 times greater than that of 6-keto-PGF_1α. The release of both PGE₂ and 6-keto-PGF_1α was enhanced by Ach and NE. The neurotransmitter-stimulated release of PGs by the iris was blocked by 654-2 in a dose-dependent manner. 654-2 at 5×10^-5 mol/L inhibited Ach-induced release of PGE₂ and 6-keto-PGF_1α by 31% and 30%, respectively. The increase in the release of PGE₂ and 6-keto-PGF_1α induced by NE at 5×10^-5 mol/L was 62% and 34%, respectively, and significantly reduced to 8% and 4%, respectively, in the presence of 654-2 at 3×10^-4 mol/L. The inhibitory effect of 654-2 on NE-induced release of PGs was not significant when the concentration of 654-2 was below 6x10^-5 mol/L. The inhibitory effects of 654-2 on neurotransmitter-induced release of PGs might contribute to its salutary effects in the treatment of septic shock.