The release of histamine by sinomenine.

Sinomenine is an alkaloid contained in the root of Sinomenium acutum Rehd. et Wilson (Fam. Menishermaceae), growing wild in southern Japan, and has long been used as a home remedy for neuralgia and rheumatism. It has a chemical structure similar to that of morphine, as shown left (1). Ishiwari (2, 3), who first isolated this alkaloid and studied its pharmacological actions, found that sinomenine caused depression of blood pressure by dilating peripheral blood vessels in mammals and acceleration of thoracic lymph flow in dogs. He (4) assumed that the foregoing therapeutic effect of this alkaloid was probably due to the increased circulation in the locus by such peripheral vascular effect.•š Augmentation of lymph rich in protein caused by sinomenine (5) is also observed in the case of histamine(6), as well as with peptone (7, 8) and ana