Central inhibition prevents the in vivo acute toxicity of harmine in mice.

BACKGROUND: Harmine is a ß-carboline alkaloid that displays antidepressant, antitumor and other pharmacological effects. However, the strong toxic effects limit its clinical application, and should be first considered. PURPOSE: To evaluate the in vivo toxicity of harmine and explore intervention strategies against its toxicity. METHODS: The in vivo toxicity of harmine was assessed from the symptoms, biochemical indices, and cardiovascular effects in mice. The intervention experiments were performed by using anesthetics, central drugs, and peripheral anticholinergics. RESULTS: The acute toxicity of harmine is significantly dose-dependent and the median lethal dose is 26.9 mg/kg in vivo. The typical symptoms include convulsion, tremor, jumping, restlessness, ataxia, opisthotonos, and death; it also changes cardiovascular function. The anesthetics improved the survival rate and abolished the symptoms after harmine poisoning. Two central inhibitors, benzhexol and phenytoin sodium, uniformly improved the survival rates of mice poisoned with harmine. The peripheral anticholinergics didn't show any effects. CONCLUSION: Harmine exposure leads to central neurological symptoms, cardiovascular effects and even death through direct inhibition of the central AChE activity, where the death primarily comes from central neurological symptoms and is cooperated by the secondary cardiovascular collapse. Central inhibition prevents the acute toxicity of harmine, and especially rapid gaseous anesthetics such as isoflurane, might have potential application in the treatment of harmine poisoning.

Collective poisoning with hallucinogenous herbal tea.

An incident wherein more than 30 people were poisoned with a herbal infusion during a meditation session is described. The clinical features observed were hallucinations, aggression, agitation, amnesia, mydriasis, dry skin, tachycardia, hyperthermia, hypotension, collapse, coma and respiratory depression. All patients recovered, although mechanical ventilation was required in some instances. A portion of the herbal infusion was found to contain atropine (hyoscyamine), scopolamine (hyoscine), harmine, and other alkaloids. The estimated ingested doses (free bases) were atropine 4 mg, harmine 27 mg, and scopolamine 78 mg. The mean concentrations in 21 serum samples obtained approximately 6h after ingestion of the infusion were atropine 5 ng/ml, harmine 8 ng/ml, and scopolamine 13 ng/ml.