Question

Local release by immune cells of which neuropeptide plays the most important role in nociception produced in areas of inflammation by the immune system? a. methionine-enkephalin. b. \(\alpha-\mathrm{MSH}\) c. \(\mathrm{ACTH}\) d. \(\beta\)-endorphin e. urocortin-1

Short answer

Answer: Urocortin-1

Step-by-step solution

Understanding the terms

Nociception is the process through which our body identifies and reacts to harmful stimuli, thus inducing the sensation of pain. Neuropeptides are small molecules that interplay neurotransmission in the nervous system and may modulate nociception depending on the particular neuropeptide involved.

Eliminating incorrect options

We can immediately eliminate some options based on their functions: a. Methionine-enkephalin: It is an endogenous opioid peptide, which has analgesic effects, meaning they attenuate pain, not cause it. b. \(\alpha-\mathrm{MSH}\) (Alpha-Melanocyte Stimulating Hormone): It is involved in pigmentation, anti-inflammatory, and neuroprotective effects; not in nociception. c. \(\mathrm{ACTH}\) (Adrenocorticotropic Hormone): It plays a role in stress response and regulation of cortisol levels; not directly involved in nociception.

Identifying the correct answer

Now we have two remaining options: d. \(\beta\)-endorphin: It is an endogenous opioid neuropeptide that is involved in pain modulation, and can induce analgesia. e. Urocortin-1: It is a member of the corticotropin-releasing factor (CRF) family and has been shown to play a significant role in inflammatory pain (nociception) through interaction with immune cells.

Concluding the answer

Based on the functions of the given neuropeptides, we can conclude that local release by immune cells of urocortin-1 (option e) plays the most important role in nociception produced in areas of inflammation by the immune system.