Psilocybe argentipes

Psilocybe argentipes (commonly known as Hikageshibiretake in Japanese) is a species of fungus in the Strophariaceae family of mushrooms. Fruit bodies grow on the ground in woody debris, and typically stand tall with caps that are in diameter. Indigenous to Japan, this species contains the hallucinogenic compounds psilocybin and psilocin. There have been reported of poisoning caused by the accidental consumption of this species. The mushroom has been used in research, specifically, to test the effects of its consumption of marble-burying in mice, an animal model of obsessive-compulsive disorder.
==History==
The species was first identified in 1973 by Japanese scientist T. Yokoyama, who believed it to be P. subcaerulipes; subsequent investigations revealed it was a unique species, and in 1976 Yokoyama published it under the name P. argentipes.
==Description==
The fruit bodies of Psilocybe argentipes have caps that are in diameter, initially conic or bell-shaped but expanding to become convex, then finally somewhat flattened in maturity. A well-defined umbo (a rounded elevation resembling a nipple) is typically present. The cap color is chestnut brown when wet, but the species is hygrophanous, and when dried, changes color to become a lighter shade of brown. Like most other psilocybin-containing species, P. argentipes stains blue where it has been bruised or injured. The cap margins of young specimens are usually curved inwards, and have irregular, wavy edges; young specimens may also have fragments of the partial veil hanging off the margin.
The gills have an adnate or adnexed attachment to the stem, which later becomes seceding; they are a grayish-orange color initially, later turning purple-brown with whitish edges. The stem is long and thick, and has roughly the same width throughout its length, except for a widening at the base due to the whitish rhizomorphs present. Initially a whitish color, it matures to become yellowish, then brown or reddish-brown. It may have white veil fragments attached to the lower two-thirds of its length.
===Microscopic features===
Viewed in deposit, as with a spore print, the spores are a dark purple-brown color. Viewed microscopically, spores are roughly ellipsoid in shape, and have dimensions of 6.5–7.5 by 9.5 by 3.3–4.4 µm. The spore-bearing cells, the basidia, are 4-spored. P. argentipes does not contain pleurocystidia (cystidia located on the face of a gill); the cheilocystidia (cystidia located on the gill edges) are 13–25 by 5–8 µm.
==Habitat and distribution==
This species grows in groups, or clustered together on the ground on soil that is rich in woody debris. It has been noted to grow near the tree species Cryptomeria japonica, Quercus galuca, and Pinus taeda. It has only been found in Japan (specifically, in Kyoto, Osaka, Shiga, Saitama, Niigata, and Miyagi), although mycologist Paul Stamets surmises it may be distributed out of Japan as well.
==Bioactive compounds==
The presence of the hallucinogenic compounds psilocybin and psilocin were confirmed by using thin-layer chromatography and column chromatography as the analytical methods. The concentration of psilocybin varied considerably depending on the locations the specimens were collected; on the basis of dry weights of the specimens, the values were from 0.003% to 0.55%. The same report also established the presence of the fungal steroids ergosterol and ergosterol peroxide.
==Effects of consumption==
There have been several Japanese reports of intoxication following accidental consumption of this species. In a report of five cases of unintentional ingestion in Miyagi Prefecture from the period 1980–84, anxiety and panic were common to all poisoning victims, even if the anxiety was preceded by an initial period of euphoria. In a later analysis of 10 cases of poisoning by this species, Musha and colleagues noted that poisoning "produced not only alterations of consciousness but also disturbances of consciousness such as strong drowsiness, short-term sleeping, fluctuation of vigilance and stuporous state with amnesia."
The effects of P. argentipes consumption on obsessive-compulsive disorder (OCD) has been tested using marble-burying behavior in mice, a commonly used animal model of OCD. When presented with an aversive stimulus such as shocks, puffs of air, or noxious food, rodents will exhibit a behavior called "defensive burying", where they will displace bedding material with their nose and forepaws; the marble-burying test takes advantage of this behavior by measuring how many glass marbles a rodent will bury under the effect of different stimuli. P. argentipes significantly inhibited marble-burying behavior, but, unlike an equivalent dose of purified psilocybin, did not affect locomotor activity; further, the mushroom was more effective than psilocybin in inhibiting the behavior, and lower doses were required. Based on these results, the authors suggest that the mushroom has the potential "to be efficient in clinical obsessive-compulsive disorder therapy".
==References==
==External links==
* Psilocybe atlantis at Index Fungorum
*Several photos
*Photo of fruit bodies
*Photos of spores and cheilocystidia
Category:Entheogens