Olfactory neurons adapt to the surrounding environment
May 2022, phys.org
This title could have had way more clickbait. The news is that we have no idea what's going on with olfactory neurons.
Not like it's ever been claimed; they just never seem to obey any sensical laws, and they're always doing things we can't understand, but now it seems that even basic assumptions about how they work are way off.
The scientists discovered an unsuspected variability in gene expression profiles depending on the expressed olfactory receptor and previous exposure to odors.And in a previous study, these scientists found that after stimulation of a receptor by an odorant molecule for less than an hour, the expression of the gene coding for this receptor decreased in the neuron, indicating a very rapid adaptation mechanism."While it was thought that the binding of an odorant molecule would only lead to the activation of the corresponding receptor, we discover that olfactory neurons drastically change their identity by modulating the expression of hundreds of genes after activation. And this new identity is again dependent on the expressed receptor. We are facing an unexpected, massive, rapid and reversible adaptation mechanism," explains Ivan Rodriguez, co-corresponding author of the study.This work reveals that olfactory neurons are not to be considered as sensors simply passing from a resting state to a stimulated state, but that their identity is in permanent evolution, not only according to the expressed receptor but also according to past experiences. This discovery adds another level to the complexity and flexibility of the olfactory system.
via Faculty of Science and the Faculty of Medicine of the University of Geneva: Luis Flores Horgue et al, Transcriptional adaptation of olfactory sensory neurons to GPCR identity and activity, Nature Communications (2022). DOI: 10.1038/s41467-022-30511-4
Image credit: Unexpected Outcome, by shironosov and Getty, 2022 - Three shocked scientists looking at the obtained substance expressing intense emotions [link]
Consider that the olfactory family of genes is evolving within us in real time. It's a huge group of genes, being the largest family there is, at 2% of the genome, and it's highly variable in the population, with a 30% variation from person to person.
Do you remember that item we learned back when the Human Genome project came out, that we share over 90% of our genome with monkeys, and almost as much with bananas? Now consider that our individual olfactory apparatus is 30% different from that of other humans. There's a lot of action here in the olfactory system.
Just wait until we figure out that it's running our immune system, because that's when things will get really crazy.