Acetylcholine decreases permeability of the sinus node to potassium, effectively hypopolarizing it
Acetylcholine closes the sodium channels of the sinus node, effectively hyperpolarizing it
Acetylcholine opens the calcium channels of the cardiac myocytes, effectively delaying repolarization
Acetylcholine closes the sodium channels of the sinus node, effectively hypopolarizing it
Acetylcholine increases permeability to potassium in of the sinus node, effectively hyperpolarizing it