YSM Issue 93.2

DOES BEING KIND MAKE
YOU FEEL LESS PAIN?
&
WHY DOES STRESS TURN
YOUR HAIR GRAY?
By Anmei Little
Have you ever noticed that politicians and CEOs develop
grey hairs fairly quickly? Usually the growth of grey
or white hairs accompanies old age due to the natural
depletion of melanocyte stem cells (MeSCs), which are responsible
for the hair pigmentation. A recent study by Ya-Chieh Hsu’s lab at
the Harvard Stem Cell Institute discovered that acute stress caused
mice to develop grey hairs by the same process as aging: MeSC
depletion. This could explain the premature greying of politicians,
CEOs, and others who experience stress on a daily basis.
In their experiment, the researchers stimulated stress in mice by
injecting them with a chemical called resiniferatoxin (RTX). RTX
acts similarly to the compound in chili peppers that is responsible
for the burning sensation of spice. In response to this stressor, the
researchers observed that the sympathetic nervous system in mice
became overstimulated and activated a “fight-or-flight” response,
releasing a neurotransmitter called noradrenaline. Noradrenaline
caused MeSCs to multiply and migrate, depleting the reservoir
and leading to premature greying. Interestingly enough, if
noradrenaline release was blocked, the mice’s hair did not lose
color. This suggests that noradrenaline is associated with, perhaps
even necessary for, the mechanism for hair greying.
While it may sound like bad news that your stress spawns
grey hairs, scientists are deeply interested in further exploring
the mechanisms of MeSC depletion. Future research may well
discover a way to prevent both stress-induced and age-induced
greying. To the next generation of politicians and leaders: do not
fret—the era of hair dye might pass soon. ■
By Selma Abouneameh
From morphine to ibuprofen, modern medicine has made
enormous progress in the field of pain management.
However, a recent study conducted by Professor Xiaofei
Xie’s lab at Peking University showed that medicine might not be
the only means by which we can attain pain relief. The proposed
alternative? Helping others.
Why do people help others? The question has plagued
scientists for centuries—after all, altruism is a costly behavior.
The researchers’ study sought to address this paradox. “Our
experiments suggest that altruism is not just other-benefiting, but
it benefits the performers as well,” said Yilu Wang, lead author of
the study. According to their results, a key benefit is pain relief.
In order to get a deeper understanding into how altruism
affects our biology, the authors conducted three experiments
that placed individuals in either altruistic or non-altruistic roles,
then either induced pain or measured naturally existing pain. In
one of these experiments, the researchers used functional MRI
(fMRI) to measure how brain activity changed after participants
performed the altruistic task of donating money to orphans.
The fMRI results showed that those who had donated money
exhibited decreased activity in the right insula, the area of the
brain responsible for feeling pain.
Thus, performing altruistic behaviors regularly can serve as
a “low-cost, side effect-free approach to supplement current
therapies for chronic pain,” Wang and Xie said. Their research
not only sheds light on different psychological and biological
motivations behind our behaviors but may also provide insight
into a new method for pain management. ■
Wang, Y., Ge, J., Zhang, H., Wang, H., & Xie, X. (2020). Altruistic
behaviors relieve physical pain. Proceedings of the National
Academy of Sciences, 117(2), 950-958.
Zhang, B., Ma, S., Rachmin, I., He, M., Baral, P., Choi, S., Gonçalves, W. A.,
Shwartz, Y., Fast, E. M., Su, Y., Zon, L. I., Regev, A., Buenrostro, J. D., Cunha,
T. M., Chiu, I. M., Fisher, D. E., & Hsu, Y.-C. (2020). Hyperactivation of
sympathetic nerves drives depletion of melanocyte stem cells. Nature,
577(7792), 676–681. https://doi.org/10.1038/s41586-020-1935-3
4 Yale Scientific Magazine September 2020 www.yalescientific.org