Ibotenic acid is an isoxazole originally isolated from Amanita mushrooms. The toxic fungi Amanita muscaria, commonly known as the fly agaric, was used to prepare the soma. The feelings of euphoria or invincibility experienced by those who drank it were eventually attributed to a group of isoxazoles centuries later. Two of these - ibotenic acid and muscimol - were first isolated from the Japanese mushroom Amanita ibotengutake in the 1960s, but found in abundance in all Amanita mushrooms. Ibotenic acid is a non-protein amino acid that is unstable and easily decarboxylated to muscimol. Ibotenic acid is a glutamate agonist, acting at glutamate receptors. Ibotenic acid is neurotoxic and used to induce cerebral lesioning in animal models.

UR-144 is a potent synthetic cannabinoid designed by Abbott Laboratories as a CB2 selective agonist for pain management and other indications. UR-144 preferentially binds the peripheral CB2 receptor (Ki = 1.8 nM) over the central CB1 receptor (Ki = 150 nM). Pre-clinical studies of nociceptive and neuropathic pain have shown that CB2-selective ligands are analgesics without causing the adverse side effects linked with CB1 receptor activation. However, UR-144 has no therapeutic application. According to the FDA (US Food and Drug Administration) there are currently no approved or on-going drug applications for the medical use of UR-144.