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 Ca . These results indicate that gymnopilin activated phospholipase C and mobilize Ca 2+ from the intracellular Ca 2+ 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.

Gymnopilin is one of the substances produced by the hallucinogenic mushroom, Gymnopilus junonius. In this study, we examined effects of gymnopilins purified from wild fruiting bodies of G. junonius on contractile activity of aorta preparations and blood pressure in rats. Gymnopilins at lower concentrations than 5 mg/mL did not evoke contraction of helical strips of the thoracic aorta. In contrast, gymnopilins (5 mg/ mL) applied to the aorta strips pre-contracted by norepinephrine (100 nM) caused relaxation. This relaxing action did not depend on the activity of the endothelium cells. The relaxing effect of 5-mg/mL gymnopilins was observed in aorta strips contracted by angiotensin II (10 nM) and the high K solution (60 mM). Moreover, the adenylyl cyclase inhibitor, SQ-22536, significantly inhibited the relaxing effect of gymnopilins at 1 mg/mL on the norepinephrine-contracted strips. These results suggested that gymnopilins acted directly on smooth muscle cells of the aorta and activated the cAMP-dependent cascade to cause the vasodilation. Paradoxically, gymnopilins injection into the jugular vein transiently increased blood pressure without affecting the heart rate. This result suggests that gymnopilins increase cardiac output and/or tension of the artery through the excitation of the vasomotor nerve that overcame the direct relaxing effect on the vascular smooth muscle.