Posted by kendoka on November 9, 2014, at 10:31:49
In reply to why do opiates help depression?, posted by rjlockhart37 on November 8, 2014, at 17:52:29
Opiates bind to the mu receptor, which inhibits GABA neurons in the VTA. The VTA is the source of most of the dopamine. Activating the mu receptor also inhibits the amygdala, helping with anxiety. Anyway,the GABA neurons in the VTA are like brakes that prevent the flow of dopamine. Turning the GABA brakes off increases the firing rate of dopamine neurons, which improves your mood by activating your mesolimbic circuit.
In depression this firing rate is dysregulated, probably due to some kind of malfunction between the limbic system and prefrontal cortex. Could be a problem with various nodes, like the caudate/putamen, the mPFC, OFC or the anterior cingulate, which have direct or indirect connections to the VTA and nucleus accumbens. I suspect asymmetry issues in the developing brain to play a role here as well.
Opiates have great antidepressant effect, but of course tolerance, addiction, and withdrawal issues become apparent with frequent use so caution is advised.
poster:kendoka
thread:1073295
URL: http://www.dr-bob.org/babble/20141017/msgs/1073300.html