What types of receptors does mitragynine, the principal psychoactive compound in kratom, primarily bind to?

Mitragynine, the principal psychoactive compound in kratom, primarily binds to mu opioid receptors and alpha-2 adrenergic receptors. The binding to mu receptors contributes to the analgesic (pain-relieving) and possibly euphoric effects that users report. However, it also has activity at alpha-2 adrenergic receptors, which can have implications for sedation and anxiolytic effects. This dual action helps to explain the varied effects of kratom, making it appealing to users seeking both pain relief and mood enhancement.

Other receptor types such as kappa opioid receptors and delta opioid receptors play roles in the opioid system as well, but they do not primarily interact with mitragynine to the extent that mu opioid and alpha-2 adrenergic receptors do. They do not account for the main pharmacological effects associated with kratom consumption, which is why they are not part of the correct answer.