Optogentic dopamine sleep switch
Gero Miesenboeck’s lab at Oxford published in the Aug 16 issue of Nature results of an experiment in which they used light to activate genes in dopaminergic neurons working as a switch that governs the wake/sleep cycle in the brain. No, their experiment was not done on humans, but instead in fruit flies, whose brains are structured similarly to our own and whose genetic expression we can control by introducing arbitrary genes and then studying the behavior they govern. After they identified a candidate class of neurons in the fruit fly brain, the team introduced a dopamine transporter gene that can be activated by light, and then discovered that activation of the gene alters the fly’s sleep cycle.
I work with the Human Nature Lab at Yale, and one one the questions that we are interested in is how humans in social networks coordinate their genetic expression. When it comes to sleep, people often tend to identify as being “early-risers”, or alternatively not being “a morning-person.” We have known for some time that levels of dopamine in the brain determine sleep patterns, and because different people have different levels of neurotransmitters normally, they can be expected also to have different sleep patterns. What is particularly interesting about the new findings published by the Oxford group is that a single type of neuron, with a particular dopamine gene, is responsible for switching the awake cycle on and off. Could it be possible that humans exhibit natural variation in the number, types or sensitivity of the sleep/awake switch in the brain? And could there be a mechanism by which humans connected in social networks can epigenetically regulate the expression of the unique gene encoding the domaine transporter responsible for the function of the switch?
It is also worth noting that demand for better sleep medications drives billions of dollars-worth pharmaceutical industry R&D and marketing efforts. Discovering sleep medications with greater target-specificity could eliminate undesirable (and sometimes) dangerous side-effects of existing sleep aides.
