Dysphoria is mediated by which opoid receptor –
**Core Concept**
Dysphoria, a state of unease or dissatisfaction, is a complex emotional response that can be influenced by various factors, including opioid use. In the context of opioids, dysphoria is a significant concern as it can occur as a side effect of these medications.
**Why the Correct Answer is Right**
Dysphoria is primarily mediated by the kappa opioid receptor (KOR). Activation of KOR is associated with anxiogenic and aversive effects, including dysphoria. This is in contrast to the mu opioid receptor (MOR), which is primarily responsible for the analgesic and euphoric effects of opioids. The kappa receptor's role in dysphoria is thought to be mediated by its activation of G-protein coupled signaling pathways, leading to the release of various neurotransmitters, including dopamine and serotonin.
**Why Each Wrong Option is Incorrect**
* **Option A:** Mu opioid receptors are primarily responsible for the analgesic effects of opioids, not dysphoria.
* **Option B:** Delta opioid receptors are involved in various physiological processes, including pain modulation and mood regulation, but are not the primary mediators of dysphoria.
* **Option D:** Sigma opioid receptors are involved in various pathological processes, including schizophrenia and cognitive impairment, but are not directly associated with dysphoria.
**Clinical Pearl / High-Yield Fact**
It's essential to recognize that kappa opioid receptor agonists can induce dysphoria, which can be a significant concern in the treatment of pain and addiction.
**Correct Answer:** C.