Glucocorticoids can alter the features of neurotransmitter systems and make them less effective
The fact that people with depression generally have higher levels of glucocorticoids due to an overactive stress-response is fitting in that the hormones can alter features of all three neurotransmitter systems of the limbic system—the amount of neurotransmitter synthesized, how fast it is broken down, how many receptors there are for each neurotransmitter, how well the receptors work, and so on. Moreover, stress has been shown to cause many of the same changes as well. Although Amygdala activity triggers the VTA to release dopamine, sustained stress will eventually deplete dopamine from the mesolimbic pathway, and norepinephrine from alerting the locus ceruleus. Moreover, stress alters all sorts of aspects of the synthesis, release, efficacy, and breakdown of serotonin. Also, excessive cortisol release has been shown to down-regulate serotonin-1a receptors. It is likely that whatever neurochemical abnormalities wind up being shown definitively link to depression, there is precedent for stress and glucocorticoids causing those same abnormalities.
References
- Sapolsky, Robert. (2004). Why Zebras Don’t Get Ulcers Chapter 14. Stress and Depression (p. 417). New York, NY: Henry Holt and Company.
Metadata
Type:🔴 Tags: Biology / Neuroscience Status:⛅️