Posted by Ritch on January 3, 2003, at 10:16:35
In reply to Re: I do believe in norepinephrine (and CRF), posted by Shawn. T. on January 2, 2003, at 22:08:16
> As a side note, the subsensitivity of norepinephrine alpha-2 receptors in depression may be a result of CRF's stimulatory effects on norepinephrine release. In other words, persistent activity due to CRF at alpha-2 receptors could decrease their responsiveness to norepinephrine. The significance of this subsensitivity is more evident if you consider the fact that the activation of alpha-2 receptors has a generally inhibitory effect on the HPA axis (but not CRF). So the desensitization of alpha-2 receptors decreases the brain's ability to counteract some of the effects of stress. Cortisol seems to cause both the down- and up- regulation of alpha-2 receptors depending on how long levels remain abnormally high, which would probably explain why people with unipolar depression can exhibit either extreme.
>
> ShawnShawn, thanks for that information. For some reason, I get rage reactions from meds (or their metabolites) that antagonize the alpha-2 adrenoreceptors. Is there a mechanism that involves the a2 receptors/CRF, etc. to explain that?
thanks in advance, Mitch
poster:Ritch
thread:133959
URL: http://www.dr-bob.org/babble/20021230/msgs/134292.html