Tuesday, 22 March 2016

Toadstool – Amanita muscaria (Fly agaric)

 One of the most iconic fungi, fly agaric, with its red cap and white spots, is renowned for its toxicity and hallucinogenic properties.
Since medieval times, fly agaric has also reportedly been used to attract and kill flies, and the ibotenic acid it contains is indeed a weak insecticide.
Toxicity of fly agaric

Fly agaric is psychoactive and hallucinogenic, containing the alkaloids muscimol, ibotenic acid (prodrug - a biologically inactive compound that can be metabolized in the body to produce a drug muscimol) and muscazone, which react with neurotransmitter receptors in the central nervous system. These cause psychotropic poisoning which may be severe in some cases although deaths are very rare. The symptoms occur in 10-30 min.
It also contains small amounts of muscarine, the first toxin to be isolated from a mushroom, and first isolated from this species.

The symptoms of muscarinic poisoning occur in about 2 hours.
  • nausea
  • blurred vision
  • sweating (cold sweat)
  • pallor
  • considerable salivation
  • lacrimation
  • abnormal heart rhythm
  • abdominal pain
  • diarrhea and vomiting
  • severe asthmatic-type breathing
  • noticeably constricted pupils (up to the size of a pinhead)
  • weakness to tremor, eyelids, tongue
  • tonic-clonic seizures in full consciousness

 These symptoms can be treated by using antidote atropine.

Atropine is found in the deadly nightshade plant (Atropa belladona). It is called the belladonna because of the effects on the pupils - dilated pupils were thought to be more attractive.