In 1863, two German chemists published a book on the properties of muscarine, a toxic alkaloid they had isolated from Amanita muscaria (Holmstedt & Liljestrand 1963; Schmiedeberg & Koppe 1869). For almost a century, muscarine was believed to be the main toxic principle of the fly-agaric. This in spite of the marked difference between fly-agaric and muscarine intoxication. Muscarine causes profuse salivation, lachrymation and perspiration, and is not psychoactive.4 These symptoms of a stimulated autonomic nervous system are generally not seen in fly-agaric inebriation. Moreover, the concentration of muscarine in European specimens of Amanita muscaria was shown to be quite low, only about 0.0003%, by no means high enough to account for the remarkable activity of this mushroom (Eugster 1956; Eugster 1353).

The problem was complicated when Schmiedeberg isolated a base from a sample of commercial muscarine which counteracted the cardiac depression of muscarine. Since atropine and related alkaloids (from Atropa belladonna and the psychoactive Mandragora and Brugmansia species; see Appendix A) have this "antimuscarinic" effect, this new compound came to be called Pilzatropin ("mushroom atropine") or alternately muscaridine (it has also been called "myceto-atropine" and "mycoatropine"; Tyler 1958a). Further confusion resulted when in 1955 it was reported that Pilzatropin was in fact an isomer of atropine, l-hyoscyamine, supposedly isolated from South African Amanita muscaria and A. pantherina (Lewis 1955). To make matters yet more confusing, bufotenine or 5-hydroxy-N,N-dimethyltryptamine (see Chapter 3) was reported as an entheogenic principle of A. muscaria (Wieland & Motzel 1953). Subsequent work has failed to substantiate the presence of either l-hyoscyamine or bufotenine in A. muscaria, and the evidence indicates that these reports were probably in error (Brady & Tyler 1959; Saleminck et al. 1963; Talbot & Vining 1963). In 1963, American chemist W.B. Cook (who had earlier worked for the CIA on phytochemistry of ololiuhqui seeds from Mexico; see Chapter 5, Note 8) published a preliminary paper on pharmacologically- active extracts from A. muscaria (Subbaratnam & Cook 1963).

Finally, in 1964, the true entheogenic principles of the fly-agaric were isolated almost simultaneously in three laboratories--in Japan (Takemoto et al. 1964a; Ta kemoto et al. 1964b; Takemoto et al. 1964c), England (Bowden & Drysdale 1965; Bowden et al. 1965) and Switzerland (Catalfomo & Eugster 1970; Eugster 1967; Eugster 1968; Eugster 1969; Eugster et al. 1965; Muller & Eugster 1965). These new compounds were isolated with the use of a fly-killing test, a fly-stunning test, and a mouse-narcosis-potentiating test respectively. In 1967, international agreement was reached as to nomenclature, and the compounds were named ibotenic acid5 and muscimol (earlier called agarin(e) or pantherine; Eugster & Takemoto 1967; Gagneux et al. 1965a; Good et al. 1965). Ibotenic acid was found to be alpha-amino3-hydroxy-5-isoxazole acetic acid; and muscimol its decarboxylation product 3hydroxy-5-aminomethy1 isoxazole (Eugster 1967; Gagneux et al. 1965b; Konda et al. 1985; Lund 1979). The isoxazole ring (5-membered, with adjacent oxygen and nitrogen atoms) is uncommon in natural products and drugs, and is found in the medicinal MAO-inhibitor isocarboxazid or Marplan (see Chapter 4; Budavari et al. 1989). A novel and pharmacologically-active isoxazole compound, premnazole, was recently isolated from two species of plants in the family Verbenaceae used in Ayurvedic medicine (Barik et al. 1992). In addition, a rearrangement product of ibotenic acid, muscazone, has been isolated from Swiss A. muscaria (Eugster et al. 1965; Fritz et al. 1965; Reiner & Eugster 1967) as well as American A. pantherina (Ott, unpublished). Muscazone is readily prepared from ibotenic acid (Chilton & Ott, unpublished; Goth 1967), may be an artifact of isolation procedures, and is of dubious psychoactivity. It is likely that either ibotenic acid or muscimol represents the Pilzatropin isolated by Schmiedeberg a century ago. A potentially psychoactive beta-carboline compound, methyltetrahydrocarboline carboxylic acid (MCTHC; I-methyl-3-carboxyl-tetrahydro-B-carboline has been isolated in low levels from European A. muscaria (Matsumoto et al. 1963). This compound is of unknown pharmacology, however, and Chilton and I were unable to detect this substance in North American A. muscaria (Chilton & Ott 1976). Two other compounds of obscure pharmacology, stizolobic acid and stizolobinic acid (also found in edible seeds of Stizolobium [Mucuna] species), have been isolated in good yield from Amanita pantherina (Chilton et al. 1974; Chilton & Ott 1976; Saito & Komamine 1978; Ott, unpublished laboratory data). These compounds have been proposed to be feeding deterrents in insects Janzen 1973), and were found to have such activity against Spodoptera but not a Cdllosobruchus species (Fellows 1984).

Besides Amanita muscaria, ibotenic acid and muscimol have been isolated from A. strobiliformis (Takemoto et al. 1964a) and A. pantherina (Chilton & Ott 1976; Takemoto et al. 1964c; see Table 6). Both compounds have been detected in A. cothurnata (=A. pantherina var. multisquamosa), A. gemmata (Beutler & Der Marderosian 1981; Chilton & Ott 1976) and in varieties alba and formosa of A. muscaria (Benedict et al. 1966; Beutler & Der Marderosian 1981; Chilton & Ott 1976). Thus far, these unusual amino acids are known to occur in no other plants.

EFFECTS OF IBOTENIC ACID AND MUSCIMOL

Ibotenic acid evokes entheogenic effects in human beings at doses ranging from 50 - 100 mg (Chilton 1975; Theobald et al. 1968). An equivalent effect is produced by 10-15 mg of muscimol (Theobald et al. 1968; Waser 1967). After oral ingestion, the onset of the inebriation is rather slow, and generally 2-3 hours elapse before the full effects are felt (Chilton 1975). This delayed response has also been reported following ingestion of Amanita pantherina (Ott 1976a). The effects last for 6-8 hours, depending on dose. Effects are characterized by visual distortions, loss of equilibrium, mild muscle twitching (not convulsions, as has erroneously been reported), and altered auditory and visual perception (Chilton 1975; Ott 1976a).

It would appear that muscimol is the psychoactive constituent, and that following ingestion of ibotenic acid, a fraction of the material decarboxylates to muscimol, which then produces the inebriation. After oral ingestion of ibotenic acid, a substantial percentage of the drug is excreted unaltered in the urine, but small amounts of muscimol are also excreted (Chilton, unpublished). This mechanism would potentially explain the Siberian urinary drug recycling practice. After ingestion of the mushroom, the celebrant would excrete substantial amounts of ibotenic acid in his urine. A second user ingesting the urine of the first, would cause some of the ibotenic acid to be decarboxylated to muscimol during digestion, producing inebriation when the muscimol was absorbed; and the bulk of the ibotenic acid would be re-excreted in his urine in turn. Thus a 100 mg dose of ibotenic acid might potentially represent four or five 10-15 mg doses of muscimol, and Steller's 1774 report that one dose of mushrooms could be recycled through four or five persons is certainly feasible. Muscimol itself probably does not play a significant role in urinary drug recycling, since it was found that only a small percentage of injected muscimol was excreted in the urine of mice (Ott et al. 1975a). This hypothesis has yet to be verified quantitatively in human beings, though it has been demonstrated qualitatively in preliminary experiments (Chilton 1979).