Final answer:
Nicotine is the neuromuscular blocker that stimulates nicotinic Ach at autonomic ganglia and muscarinic receptors on the heart, causing depolarization and activation of sympathetic and parasympathetic systems.
Step-by-step explanation:
The neuromuscular blocker that stimulates nicotinic Ach at autonomic ganglia and muscarinic receptors on the heart is nicotine. Nicotine acts as an ACh analog and binds to the ACh receptors on the ganglionic neurons, causing depolarization. This leads to the activation of the sympathetic and parasympathetic systems, which control heart function.