Question

There are ---- subtypes of alpha receptors (α1 andα2 )

and ---- subtypes of beta receptors (β1 andβ2 ).

Answer 1

There are two established subtypes of alpha receptors (α1 and α2) and three subtypes of beta receptors (β1, β2, and β3).

Step-by-step explanation:

There are two subtypes of alpha receptors (α1 andα2) and three subtypes of beta receptors (β1, β2, and β3). The alpha adrenergic receptors are involved in various responses such as vasoconstriction and pupillary dilatation, whereas beta receptors are largely related to the relaxation of smooth muscle tissues and the increment of heart rate. It is important to note that there is some discrepancy in sources regarding the existence of a third alpha (α3) adrenergic receptor; however, the more commonly accepted notion at present is that there are only two, α1 and α2, as the presence of α3 is not as well documented or recognized.