This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
[{'content': 'Site of action of epidural analgesia \nSelect and explain. \nA. Sensory nerve endings, B. Ventral horn, C. Substantia gelatinosa, D. Coex', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Substantia gelatinosa Opoid receptors are maximum in Lamina 2 (substantia gelatinosa) Lamina 5 of spinal cord. So Epidural Narcotics acts mainly on substantia gelatinosa Common side effects of intraspinal/ epidural opioids are pruritis (itching), nausea - vomiting; urinary retention, sedation, ileus and dose dependent respiratory depression (most serious)Q', 'role': 'assistant'}]