The neurotransmitter released at the neuromuscular junction of skeletal muscle is

Explanation

Acetylcholine diffuses across the synaptic cleft and depolarises the sarcolemma, and the resulting action potential spreads down the T tubules to release calcium. The enzyme cholinesterase then destroys it quickly, so each nerve impulse produces one twitch rather than continuous contraction. Nerve gases and some insecticides are lethal because they block that enzyme.