Serotonin receptors expressed in a specific type of neuron in the brain regulate insulin sensitivity in the liver, reports a study published online this week in Nature Neuroscience.
Previous work has implicated brain serotonin receptors, specifically the 2C subtype, in the regulation of whole body energy balance and glucose homeostasis. Joel Elmquist and colleagues took advantage of genetically-modified mice lacking the serotonin 2C receptor to delve further into the identity of the neurons mediating these effects. They find that mice lacking the serotonin 2C receptor displayed insulin resistance in the liver. This resistance was ameliorated when the expression of the serotonin 2C receptor was restored in a specific group of neurons, the pro-opiomelanocortin (POMC)-expressing neurons, in the arcuate nucleus of the hypothalamus — a brain region critical for regulation of feeding and glucose homeostasis.
The authors also found that serotonin 2C receptor expression in POMC neurons was sufficient to mediate the anti-diabetic effects of a drug that targets these receptors. These findings in mice provide potential insight into blood glucose control in humans.