Which symptom is NOT typically associated with nerve agent exposure?

Nerve agents are a class of chemical warfare agents that primarily affect the nervous system by inhibiting the enzyme acetylcholinesterase, leading to an accumulation of the neurotransmitter acetylcholine. This results in a series of symptoms that reflect the excessive stimulation of muscles and glands.

Miosis, or constricted pupils, occurs because the excessive acetylcholine leads to prolonged stimulation of the muscles that control pupil size. Salivation, another symptom, happens due to overstimulation of the salivary glands, causing excessive drooling. Muscle twitching can also be observed, as the overstimulation of muscles can lead to involuntary contractions or spasms.

In contrast, increased heart rate is typically not a symptom of nerve agent exposure. Instead, nerve agent exposure frequently results in bradycardia, a decreased heart rate, due to the parasympathetic actions of acetylcholine flooding the system. Thus, the correct answer is the symptom that does not align with the characteristic responses to nerve agent exposure.