Cyprodime is a selective opioid antagonist which blocks the μ-opioidreceptor, but without affecting the δ-opioid or κ-opioid receptors. This makes it useful for scientific research as it allows the μ-opioid receptor to be selectively deactivated so that the actions of the δ and κ receptors can be studied separately, in contrast to better known opioid antagonists such as naloxone which block all three opioid receptor subtypes.
Tianeptine, an atypical, selective MOR full-agonist licensed for major depression since 1989.
Samidorphan, an opioid antagonist preferring the MOR, which is under development for major depression.
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