@Mars - I did a search on Google scholar using: redhaired people pain threshold as keywords and these were the first two hits:
Decreased Local Anesthetic Efficacy in Subjects with Naturally Red HairEdwin B. Liem, M.D., Teresa V. Joiner, B.S.N., Kentaro Tsueda, M.D., Daniel I. Sessler, M.D.
Outcomes Research Institute and Department of Anesthesiology, University of Louisville, Louisville, Kentucky.
Conclusion: A recent study demonstrated that desflurane requirement is greater in redheaded women.1 That finding is extended by our current observation that subcutaneous lidocaine is less effective in redheads than in subjects with dark hair. However, our current results also indicate that pain sensitivity in the absence of drugs is independent of hair color. Increased anesthetic requirement and reduced efficacy of subcutaneous lidocaine in redheaded women thus appear to be pharmacodynamic effects.
and
Increased Sensitivity to Thermal Pain and Reduced Subcutaneous Lidocaine Efficacy in Redheads
Edwin B. Liem, M.D.,* Teresa V. Joiner, B.S.N.,† Kentaro Tsueda, M.D.,‡ and Daniel I. Sessler, M.D.§
Conclusion: Red hair is the phenotype for mutations of the melanocortin 1 receptor. Our results indicate that redheads are more sensitive to thermal pain and are resistant to the analgesic effects of subcutaneous lidocaine. Mutations of the melanocortin 1 receptor, or a consequence thereof, thus modulate pain sensitivity.
from the introduction:
Red hair nearly always results from mutations of melanocortin-1 receptor gene (
MC1R).
1-
3 The human melanocrotin-1 receptor (MC1R) is expressed on the surface of melanocytes and is a key regulator of intracellular signaling to the melanin biosynthetic pathway governing pigment formation. In general, the balance of pheomelanin (yellow-red) and eumelanin (dark brown) pigments determines hair and skin color in the Caucasian population.
4 The red hair phenotype results from excess pheomelanin production due to dysfunctional MC1Rs.
5,
6 In contrast, when a normal (consensus) MC1R is expressed, the predominant pigment produced by melanocytes is eumelanin resulting in a high eumelanin to pheomelanin ratio.
In a previous study,
we found that women with red hair required 19% more desflurane to suppress movement in response to noxious electrical stimulation than women with dark hair,
making red hair a distinct phenotype associated with anesthetic requirement in humans.
7
Always happy to help prove an INTP right
Just wanted to see if anyone else would bite, lol.
