Pharmacology Botulinum toxin blocks neuromuscular transmission by which of the following mechanism: A Closure of Ca++ channels at presynaptic membrane B Closure of Na+ channels at the postsynaptic membrane C Opening of K+channels at the presynaptic membrane D Opening of Cl– channels at the postsynaptic membrane 💡 Explanation Botulinum toxin blocks neuromuscular transmission by which of the following mechanism: ✓ Correct Answer: A. Closure of Ca++ channels at presynaptic membrane