To really grasp the impact of norepinephrine on panic and anxiety, we need to understand the action of what are called feedback loops. And we need to learn how norepinephrine influences serotonin.
Now, most any system, biological or otherwise, has input and output capabilities. When the output of a system in some manner loops back to the system as input, and influences its functioning, a feedback loop has been established.
A positive feedback loop increases system output, a negative feedback loop decreases it.
There is a feedback loop relationship between norepinephrine and serotonin. According to design, as serotonin levels are sufficiently maintained, so are levels of norepinephrine.
Now, when supplies of serotonin run low, levels of norepinephrine increase in an effort to ramp-up serotonin levels. And when serotonin levels, indeed, rise; levels of norepinephrine recede in kind. This may result in a decrease in anxiety.
So if an individual’s brain can’t maintain sufficient levels of serotonin, and norepinephrine can’t stimulate a boost, the presence of serotonin plummets; the result of which is thought to be symptoms of anxiety and depression.
You know, it’s interesting that some forty years ago the panic pioneer, D.F. Klein, M.D., made the observation that imipramine (Tofranil), a tricyclic antidepressant that impacts norepinephrine, terminated panic. Or at least greatly reduced its frequency and intensity. By the way, the very first med I was prescribed for my panic situation was imipramine. That was in 1989.
The theory that specific neurotransmitters had much to do with the dynamics of panic gained a ton of notoriety and momentum as a result of Dr. Klein’s work. And research over the next twenty-some years underscored his hypotheses.
Tune in tomorrow and we’ll talk about epinephrine (adrenaline), and perhaps wrap-up the series.
Between now and then, will you review all three posts and assess what you’ve learned thus far?