Tomihiro Hayakawa, Kenji Katagiri, Makoto Hoshino, Tomio Nakai, Takayuki Ohiwa, Tomoyuki Kumai, Makoto Miyaji, Toshihiko Takeuchi, James Corasanti, James L. Boyer – 1 October 1992 – Papaverine is a nonspecific smooth muscle relaxant and a phosphodiesterase inhibitor. Its effects on biliary excretion of lipids and horseradish peroxidase were investigated in a single‐pass isolated perfused rat liver model. A constant infusion of papaverine (1.6 μmol/min; 40 μmol/L) significantly increased bile flow (microliters per minute per gram of liver) before (2.03 ± 0.09 vs.