Okay, we’re gonna’ tie a bow on our norepinephrine series by first chatting about epinephrine and the HPA axis.
Epinephrine, a hormone and neurotransmitter synthesized in the adrenal glands , is involved with our reaction to immediate stress, prompting our physiological responses to threatening or highly stimulating environmental stressors.
The HPA axis is a cortisol generating stress response system starring the hypothalamus, the pituitary gland, and the adrenals.
When released into the bloodstream by the adrenal glands, prompted by norepinephrine, epinephrine has significant influence throughout the body. It increases heart stroke volume and rate, dilates the pupils, constricts arterioles in the skin and abdomen, and dilates arterioles in the leg muscles.
Epinephrine also supports our threat reaction by elevating blood sugar levels. Anything having to do with epinephrine and its functioning is adrenergic.
Now, in so-called “healthy” individuals the noradrenergic (norepinephrine) system and the HPA axis work in harmony through, as we discussed, feedback loops, in maintaining a sense of stress-balance. When everything is operating as it should, as activity in the noradrenergic system increases, activity in the HPA axis follows suit.
But in panic and anxiety sufferers this delicate balance is interrupted by chronic and/or situational overproduction of norepinephrine, which messes up the whole works. As a result, the HPA axis becomes cut off from any and all noradrenergic activity, leading to an unmanaged increase in stress.
The term dysregulation refers to the inability of a neural system to maintain a balance of its intended neurotransmitter activity. If you haven’t caught on as yet, noradrenergic activity in panic and anxiety sufferers is theorized to be highly susceptible to dysregulation because of all of the funny business mentioned in the last paragraph.
And the success of the ever-popular selective serotonin reuptake inhibitors (SSRI’s) in the treatment of panic and anxiety may well be due to normalization of a “dysregulated” noradrenergic system by the enhancement of serotonin activity. As we discussed, as serotonin levels rise, levels of norepinephrine fall.
Well, that’s going to do it for our four-part series on norepinephrine. Hopefully you’ve learned a lot. And, as I always say; when we’re learning we’re growing and becoming, and staying, well.
What will you do with your new insight?