Amanita muscaria (fly agaric): from a shamanistic hallucinogen to the search for acetylcholine.

The mushroom Amanita muscaria (fly agaric) is widely distributed throughout continental Europe and the UK. Its common name suggests that it had been used to kill flies, until superseded by arsenic. The bioactive compounds occurring in the mushroom remained a mystery for long periods of time, but eventually four hallucinogens were isolated from the fungus: muscarine, muscimol, muscazone and ibotenic acid. The shamans of Eastern Siberia used the mushroom as an inebriant and a hallucinogen. In 1912, Henry Dale suggested that muscarine (or a closely related substance) was the transmitter at the parasympathetic nerve endings, where it would produce lacrimation, salivation, sweating, bronchoconstriction and increased intestinal motility. He and Otto Loewi eventually isolated the transmitter and showed that it was not muscarine but acetylcholine. The receptor is now known variously as cholinergic or muscarinic. From this basic knowledge, drugs such as pilocarpine (cholinergic) and ipratropium (anticholinergic) have been shown to be of value in glaucoma and diseases of the lungs, respectively.

Rhubarb (Rheum species): the role of Edinburgh in its cultivation and development.

Rhubarb was grown and used throughout China for thousands of years. It then found its way to St Petersburg where the Romanovs developed a flourishing trade in the plant to the rest of Europe. James Mounsey, a physician to the Tsar, brought back seeds from Russia to Scotland at considerable risk to himself. He passed some of the seeds to Alexander Dick and John Hope. Both these physicians then grew rhubarb at Prestonfield and the Botanic Garden (both in Edinburgh), respectively. Eventually rhubarb, in the form of Gregory's powder, became a common and popular medicine throughout the UK.