What type of receptor does phenylephrine primarily act on?

Phenylephrine primarily acts on α-adrenergic receptors, which are part of the sympathetic nervous system. These receptors are mainly located on vascular smooth muscle, and their activation leads to vasoconstriction, which ultimately results in an increase in blood pressure. This action is particularly useful in clinical settings where there is a need to counteract hypotension or maintain perfusion pressure.

The specificity of phenylephrine for α-adrenergic receptors distinguishes it from other medications that may have broader effects. For instance, β-adrenergic receptors, when stimulated, typically lead to vasodilation and increased heart rate, which is contrary to the effects of phenylephrine. Moreover, V1 receptors primarily mediate vasopressor effects elsewhere, while muscarinic receptors are associated with parasympathetic functions, such as stimulation of salivary secretion and decreased heart rate. Therefore, understanding the receptor subtype that phenylephrine targets is crucial for comprehending its pharmacological effects and appropriate clinical applications.