Gymnopilin-a substance produced by the hallucinogenic mushroom, Gymnopilus junonius-mobilizes intracellular Ca2+ in dorsal root ganglion cells

Gymnopilus junonius is a widely spread mushroom in Japan and well known as a hallucinogenic mushroom. Gymnopilin was purified from the fruiting body of G. junonius and was reported to act on the spinal cord and depolarize motoneurons. This is the only evidence that gymnopilin has a biological effect on animals and no mechanism of the action has been determined at all. In this study, we examined effects of gymnopilin on intracellular Ca2+ concentrations ([Ca2+]) of cultured cells isolated from the dorsal root ganglion (DRG) of the rat. The cell culture consisted of neurons and non-neuronal cells. Gymnopilin increased [Ca2+](i) in both the types of cells. The gymnopilin-evoked [Ca2+](i) rise in the non-neuronal cells was inhibited by cyclopiazonic acid and U-73122, inhibitors of Ca2+-ATPase of the intracellular Ca2+ store and phospholipase C, respectively, but not by removal of extracellular Ca2+. These results indicate that gymnopilin activated phospholipase C and mobilize Ca2+ from the intracellular Ca2+ store in non-neuronal cells from the DRG. This is the first report to show that gymnopilin directly acts on cells isolated from the mammalian nervous system.