Question

What are the names and sources of peripheral mediators that produce activation and sensitization of nociceptor endings?

Answer 1

The nociceptors carry pain sensation to the brain. The nociceptive nerve endings are activated through various peripheral mediators such as :

1. Bradykinin : released from mast cells and damaged tissue cells. Bradykinin is produced by proteolytic cleavage of high-molecular-weight kininogen by the enzyme kallikrein.

2. Histamine : released by mast cells and basophils.

3. Serotonin : secreted by platelets

4. Acetylcholine : secreted by cholinergic nerve endings upon activation of autonomic nervous system.

5. Prostaglandin : secreted by inflammatory nucleated cells such as mast cells.

6. Substance P : secreted by macrophages, eosinophils, lymphocytes, and dendritic cells.

7. Interleukins : secreted by helper CD4 T lymphocytes, macrophages, monocytes and endothelial cells.

8. Leukotrienes : secreted by mast cells, eosinophils, neutrophils, monocytes, and basophils.