Anhedonia and depression arise when POMC neurons in the arcuate nucleus of the hypothalamus become hyperactive as a result of chronic stress. Reducing the activity also reduces feelings of depression and loss of pleasure.
In mice genetically more susceptible to PTSD following a stressful event, researchers found an increased expression of cortisol receptors on neurons in the CA1 region of the dorsal hippocampus. Those increased receptors enabled an elevated expression of the HCN1 protein and TRIP8b, reducing neural excitability.
MicroRNAs that should attack SARS-CoV-2, the virus that causes COVID-19, diminish with age, and due to chronic health problems. The findings shed light on why those who are older, and those with health conditions are more susceptible to coronavirus.