这个词是什么意思？
An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels.
中文名称索引；定义为 MeSH 英文原文，尚未逐条译审。MESH:D010208 · MeSH 2026。
Courtesy of the U.S. National Library of Medicine. Annual snapshot; later updates may not be reflected. NLM does not endorse this service.