Which receptor stimulation is primarily associated with CNS depression both at the spine and above?

The Mu Opioid Receptor is primarily associated with central nervous system (CNS) depression that occurs both at the spinal cord level and in higher brain regions. This is primarily due to the role that Mu receptors play in modulating pain and analgesia, where their activation results in decreased perception of pain and sedation. When opioids bind to these receptors, they inhibit neuronal excitability and decrease the release of neurotransmitters associated with pain signaling, leading to a reduction in overall CNS activity.

Mu receptors are critical targets for opioid analgesics, which are widely used for pain management. Their effects include not just analgesia but also sedation and euphoria, which contribute to the overall CNS depressant effects. In contrast, Kappa and Delta receptors do have roles in the opioid system and can also impact mood and pain, but their effects are not as strongly associated with widespread CNS depression as those mediated by the Mu receptor. Full agonist refers more to the action of certain drugs rather than a specific receptor and does not pinpoint the mechanism in the context of CNS depression as distinctly as the Mu receptor does.