Table 3.

Opioid receptors, site of action and their effects.

Receptor	Site of Action	Effects	References
MOR	Systemic	Analgesia, euphoria, constipation, respiratory depression, Nausea/vomiting	[32,38,39,40,41,42,43,44,45,46]
	Peripheral	Analgesia, constipation, reduced inflammation	[40,42,47,48,49,50]
DOR	Systemic	Analgesia, convulsions, anxiolysis	[51,52,53]
	Peripheral	Analgesia, Decreases colonic transit time (constipation),	[48,54,55]
KOR	Systemic	Analgesia, diuresis, dysphoria	[56,57]
	Peripheral	Analgesia, reduced inflammation, Visceral nociception antagonist	[25,39,58,59,60]