Reflex bradycardia

Reflex bradychardia is a hormone activated response mechanism that results from an insufficient Mean Arterial Pressure, or from an irregular Pulmonary tachycardia. This reflex mechanism is conduced through a second messenger system; ACDH production in the anteriorpituitary is stopped thereby diminishing blood levels of cortisol. Transient depolarization of (nor)epinephrine neurotransmitters in the adrenal medulla now becomes repressed. The parasympathetic nervous system homeostatically maintains membrane potentials in the neuromuscular junctions of the pace-making cells. Most importantly EKG of the patient will now be stable; the QRS complex now innervates normal electrical signals.

More information regarding Dopamine's interaction in this response is not well documented.