Final answer:
The G protein-coupled receptors in question that have 5 subtypes in the CNS and peripheral tissue are adrenergic receptors, which include both alpha and beta subtypes and are activated by adrenaline and noradrenaline.
Step-by-step explanation:
Adrenergic receptors, which are G protein-coupled receptors found in the central nervous system (CNS) and peripheral tissue, exist in 5 subtypes. The adrenergic system is characterized by two main groups: alpha (α)-adrenergic and beta (β)-adrenergic receptors. Of these, there are three subtypes of α-adrenergic receptors (α₁, α₂, and α₃) and three subtypes of β-adrenergic receptors (β₁, β₂, and β₃). These receptors are activated by their endogenous ligands, the catecholamines adrenaline (also known as epinephrine) and noradrenaline (also known as norepinephrine), which trigger a sympathetic response, such as an increase in heart rate and a diversion of blood flow to skeletal muscle.
In contrast, serotonin receptors also fall into the category of G protein-coupled receptors but they encompass a wider variety and a larger number of subtypes beyond just five, which does not align with the question's specification. As for dopamine and opioid receptors, they too are G protein-coupled receptors but they don't match the specific characteristics laid out in the question.