Neurotropic Effect of Extracts from the Hallucinogenic Mushroom Psilocybe cubensis (Earle) Sing. (Agaricomycetideae). In Vitro Studies

Extracts from the mushroom Psilocybe cubensis, containing the hallucinogens psilocybin and psilocine, inhibit the electrical activity of pyramidal neurons in the rat hippocampal CA1 region. Of 50 neurons recorded, 73.5% showed inhibition from biomass extract and 81% from fruiting body extract, with inhibition lasting about 4–5 minutes. Excitation was rare, occurring in only 5.9% of neurons with biomass extract and none with fruiting body extract. The serotonin receptor antagonist ritancerin blocked these inhibitory responses in half the cells tested. The extracts also inhibited excitation caused by L-glutamic acid. These results suggest that psilocybin-containing extracts produce a similar inhibition pattern in hippocampal neurons and can suppress glutamate-induced excitation.

Study at a glance

Abstract

The neurotropic effect of Psilocybe cubensis (Earle) Sing, dried biomass and fruiting bodies containing the indole hallucinogens psilocybin and psilocine on spike activity of pyramidal neurons from the rat hippocampal CAl region slices has been studied. Extracellularly responses of 50 neurons were recorded, 34 during the application of biomass extract (BME) and 16 during the application of fruiting body extract (FBE). Of the total number of cells studied, the inhibition resulting from BME and FBE application was observed in 73.5% and 81% of cells, respectively. Inhibition parameters during the BME and FBE application were (in seconds) as follows: latency 59 ± 7 and 67 ± 8 and duration 251 ± 26 and 273 ± 37, respectively. Only 5.9% of neurons showed excitation resulting from BME application and no excitative response was observed during FBE application. During the BME and FBE application a short burst occurred in 29% and 12.5% of neurons, respectively. Ritancerin (antagonist of 5-HT2/5-HT1C serotonin receptors) blocked inhibitory responses resulting from BME and FBE application in half of the units tested. The duration of response to serotonin could reach 10−43 min whereas the response to extract application usually did not exceed 4−5 min. Extract application inhibited excitation spike responses resulting from L-glutamic acid application. Results that have been obtained show that the application of psilocybin-containing extracts from mushroom fruiting bodies and biomass causes a similar inhibition pattern of spike activity in pyramidal neurons from the hippocampal CA1 region and inhibits excitation of these neurons caused by L-glutamic acid.