Acetylcholine and the Cholinergic Receptors

Effector organs Response Receptor type Response 

S-A node Decrease in heart rate Vagal arrest P Increase in heart rate 

Atria Decrease in contractility and (usually) increase in conduction velocity P Increase in contractility and conduction velocity 

A-V node and conduction system Decrease in conduction velocity A-V block P Increase in conduction velocity 

Ventricles P Increase in contractility, conduction velocity, automaticity, and rate of idiopathic pacemakers 

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FIGURE 5.2 (See color insert following page 46.) Presynaptic and postsynaptic regions of the acetylcholine neuron, emphasizing the synthesis and degradation of acetylcholine and the cholinergic receptor suhtypes (Panel [A]) summary of the peripheral nervous system that utilizes acetylcholine as the transmitter (Panel [ B]). 

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