Which plants have neuromuscular (nicotinic) effects?

• A. Poison Hemlock (Conium), Larkspur (Delphinium), Goldenchain (Laburnum), Cardinal Flower plus Giant Lobelia (Lobelia)
• B. Nightshade family such as Lycopersicon (Tomato), Physalis (Ground Cherry), Solanum
• C. Aster family such as Helianthus (Sunflower)
• D. Poison Ivy and Poison Oak

Answer: (A)

Plants with neuromuscular (nicotinic) effects carry alkaloids that interact with nicotinic acetylcholine receptors at the neuromuscular junction and in autonomic ganglia. This can cause an initial overstimulation (twitching, tremors) followed by weakness or paralysis, and can be fatal if respiration is impaired.

The best example group includes poison hemlock, larkspur, golden chain, and Lobelia. Poison hemlock provides coniine, a classic nicotinic-acting toxin. Larkspur contains potent nicotinic receptor–active alkaloids such as methyllycaconitine, which disrupt neuromuscular transmission. Golden chain (Laburnum) contains cytisine, a nicotinic receptor agonist, producing nicotine-like effects. Lobelia (cardinal flower and giant lobelia) contains lobeline, another alkaloid with nicotinic activity. Together, these plants are known for causing neuromuscular nicotinic symptoms in exposed animals or people.

The other groups don’t primarily produce these nicotinic neuromuscular effects. Nightshade family members have alkaloids with anticholinergic or other mechanisms rather than targeted nicotinic neuromuscular action. The Aster family and plants like poison ivy/oak cause different toxic effects (such as dermatitis) rather than neuromuscular nicotinic toxicity.