Final answer:
The statement that opioid receptors only act as monomers is b) false; they can also form dimers and oligomers, affecting their signaling and function.
Step-by-step explanation:
The statement that opioid receptors only act as monomers is b) false.
Opioid receptors, like many other G-protein coupled receptors (GPCRs), can function not only as monomers but also as higher-order structures such as dimers and oligomers.
This capacity to form such structures can affect the pharmacology, signaling, and regulation of these receptors, thus influencing the response to opioids.
There has been considerable research into the dimerization and oligomerization of opioid receptors, which has provided insights into their function and the complexity of their signaling mechanisms.