Mushrooms' Muscaria Magic: A Guide To Their Power

Muscarine is a natural product found in certain mushrooms, particularly in Inocybe and Clitocybe species. It was discovered in 1869 and was long thought to be the active hallucinogenic agent in Amanita muscaria mushrooms. However, researchers in England, Japan, and Switzerland showed that the effects were mainly due to ibotenic acid and muscimol, not muscarine. Mushrooms containing muscarine are commonly found in yards, parks, and wooded areas throughout the United States, Europe, and Asia. Ingesting these mushrooms can lead to mushroom poisoning and potentially fatal results. Symptoms of muscarine intoxication include sweating, facial flushing, salivation, vomiting, abdominal cramps, diarrhea, urination, and in more severe cases, bradycardia, hypotension, and dizziness. There is no specific antidote for muscarine toxicity, but atropine and symptomatic supportive care can help in reversing the symptoms.

Muscarine-containing mushrooms are poisonous and can be fatal

Mushrooms are a type of fungus that can be found in many shapes, sizes, and colours. While some mushrooms are edible and nutritious, others are poisonous and can be fatal if consumed. One type of toxic mushroom is muscarine-containing mushrooms.

Muscarine, L-(+)-muscarine, or muscarin is a natural substance found in certain mushrooms, particularly in Inocybe and Clitocybe species. Mushrooms in the genera Entoloma and Mycena also contain levels of muscarine that can be dangerous if ingested. The name "muscarine" comes from the Latin word "musca," meaning fly, as the mushroom was often used to attract and catch flies. Its discovery is credited to German chemists Oswald Schmiedeberg and Richard Koppe at the University of Tartu in 1869.

Muscarine mimics the function of acetylcholine, a natural neurotransmitter in the cholinergic nervous system. It selectively binds to and activates muscarinic acetylcholine receptors (M1-M5), causing excessive stimulation of these receptors. This leads to a range of toxic symptoms, including excessive perspiration, lacrimation, and salivation, known as PSL syndrome. Other symptoms include blurred vision, miosis, vomiting, abdominal pain, diarrhoea, bradycardia, lowered blood pressure, dyspnea, congested pulmonary circulation, bronchorrhea, and urinary incontinence. The onset of symptoms is rapid, usually occurring within 30 minutes to two hours of ingestion.

The toxicity of muscarine-containing mushrooms depends on the concentration of muscarine present. Inocybe and Clitocybe mushrooms have the highest muscarine concentrations, up to 1.6%, resulting in higher chances of mushroom poisoning and potentially fatal outcomes. According to data, consuming 500 grams of raw Inocybe or Clitocybe mushrooms can contain a lethal dose of muscarine for humans. In contrast, Amanita muscaria mushrooms have much lower muscarine content, typically around 0.0003% of the mushroom's fresh weight, making extreme toxicity and fatalities unlikely.

While mild muscarinic toxicities may not require specific treatment beyond adequate hydration, severe cases demand immediate medical attention. There is no specific antidote for muscarine mushroom toxicity, but atropine administration and symptomatic supportive care can help manage symptoms. However, education about the poisonous nature of wild mushrooms is essential to prevent accidental ingestion and reduce the risk of mushroom poisoning.

The symptoms of muscarine poisoning include sweating, facial flushing, vomiting, and hypotension

Mushrooms are a delicacy in many parts of the world, but only 200-300 of the 5,000 known species have been established as safe for consumption. Poisoning from wild mushrooms can occur due to ingestion of toxins, and muscarine is one such toxin. It was first isolated from the mushroom Amanita muscaria in the 1800s and is also found in some Inocybe and Clitocybe species.

The onset of symptoms varies, with some people experiencing gastrointestinal upset within 20 minutes to 4 hours of ingestion, while others may not show serious symptoms until the toxin attacks the kidneys or liver, which could be days or weeks later. The symptoms of muscarine poisoning from mushrooms start early, usually within one to two hours, with a headache, nausea, vomiting, and pharynx constriction. This is followed by excessive salivation, sweating, and blurred vision.

Mushroom poisoning with muscarinic toxidrome can present a variety of signs and symptoms, even among people who ingested mushrooms from the same patch. Accurate diagnosis of muscarine poisoning should be based on recognising common muscarinic manifestations, such as excessive sweating, salivation, and bladder cramping. In cases of severe muscarinic poisoning, patients may be administered intravenous crystalline fluids and bolus injections of atropine.

Mushrooms from the Inocybe and Clitocybe genera contain the highest concentrations of muscarine

The symptoms of intoxication with mushrooms rich in muscarine, especially Inocybe, are very typical and start early, within 15 to 120 minutes. The symptoms include headache, nausea, vomiting, and constriction of the pharynx. This is followed by excessive perspiration, lacrimation, and salivation (PSL syndrome), as well as miosis, disturbed accommodation, and reduced vision. Gastric and small bowel colic lead to diarrhea, along with a painful urge for urination. Bronchoconstriction causes asthmatic attacks and severe dyspnea, while bradycardia, marked hypotension, and vasodilation result in circulatory shock. Death after 8 to 9 hours has been reported in about 5% of cases.

The high concentrations of muscarine in Inocybe and Clitocybe mushrooms result in a higher risk of mushroom poisoning and potentially fatal outcomes. However, prompt administration of IV or IM anticholinergic drugs, such as atropine, can effectively treat severe muscarinic symptoms and prevent death. Atropine is a specific antidote for muscarine poisoning, but it is toxic and should only be administered by a qualified physician.

Inocybe and Clitocybe mushrooms produce muscarine, a natural product that mimics the function of acetylcholine, a natural neurotransmitter in the muscarinic part of the cholinergic nervous system. Muscarine binds to muscarinic acetylcholine receptors, and its action is slower but longer-lasting compared to acetylcholine. This prolonged effect may be due to muscarine's resistance to hydrolysis by acetylcholinesterase in the synaptic cleft.

Muscarine mimics acetylcholine, a natural neurotransmitter

Muscarine is a natural product found in certain mushrooms, particularly in Inocybe and Clitocybe species, such as the deadly C. dealbata. Mushrooms in the genera Entoloma and Mycena have also been found to contain dangerous levels of muscarine when ingested. Inocybe and Clitocybe mushrooms contain the most significant muscarine concentrations (up to 1.6%), resulting in higher chances of mushroom poisoning and potentially fatal results.

Acetylcholine is a neurotransmitter that plays a role in cognitive functioning and is involved in various physiological processes in the body, including heart rate, smooth muscle contraction, pupil constriction, and vasodilation of blood vessels. It binds to muscarinic and nicotinic receptors, which are classified based on two chemical agents that mimic the effects of acetylcholine at the receptor site: nicotine and muscarine.

The activation of muscarinic receptors can be either excitatory or inhibitory, and it is always slow in onset and long in duration. Muscarine, as a muscarinic agonist, can overstimulate these receptors, leading to harmful effects such as increased parasympathetic response, which is associated with certain diseases like COPD and asthma. Overstimulation of muscarinic receptors can also lead to overactive bladder syndrome, where the detrusor muscle is overactive, causing urinary frequency, urgency, and incontinence.

The symptoms of muscarine intoxication from mushrooms are well-defined, and there are treatments available for severe symptoms, including atropine administration and hemodynamic monitoring. However, there is no specific antidote for muscarinic mushroom toxicity, and mild cases can be managed with adequate hydration.

There is no antidote for muscarine poisoning, but atropine can help reverse the symptoms

Mushrooms containing muscarine are considered poisonous and are often accidentally ingested due to being mistaken for edible mushrooms. The symptoms of muscarine poisoning include sweating, salivation, tears, blurred vision, palpitations, and, in high doses, respiratory failure. In around 5% of cases, death can occur within 8 to 9 hours of ingestion.

While there is no antidote for muscarine poisoning, atropine can be used to reverse the symptoms. Atropine is a muscarinic antagonist, which competitively blocks the effects of acetylcholine and other choline esters on muscarinic receptors. It is a relatively inexpensive drug and is included in the World Health Organization List of Essential Medicines. Atropine can be administered intravenously, subcutaneously, intramuscularly, intraosseously, or endotracheally. The dose for adults is 1-2 mg IV, and for children, it is 0.02-0.05 mg/kg IV.

It is important to note that atropine is not indicated in cases of poisoning by ibotenic acid or muscimol, which are also found in some mushrooms that contain muscarine. In dogs, the use of atropine with any of these species can easily cause death. Therefore, it is crucial to seek medical advice and not self-administer atropine in the event of suspected muscarine poisoning.

Additionally, measures to replace fluids and electrolytes can speed up recovery from mushroom poisoning. Overall, prompt medical intervention is necessary to prevent serious health consequences or death from muscarine poisoning.

Frequently asked questions