Quoted article starts by saying: “Many painful conditions occur more frequently in women, and estrogen is a predisposing factor. Estrogen may contribute to some pain syndromes by enhancing axon outgrowth by sensory dorsal root ganglion (DRG) neurons.” This effect may be blocked by ACE inhibitors
Endocrinology. 2008 Apr 3 [Epub ahead of print]
Estrogen Elicits Dorsal Root Ganglion Axon Sprouting via a Renin-Angiotensin System.
Chakrabarty A, Blacklock A, Svojanovsky S, Smith PG.
Estrogens help induce “sciatica area” nerve sprouts
There experiments demonstrated estrogen upregulates regional angiotensin II receptors and this induced neurogenesis (new nerve outsprouts that could be painful) in the mouse model.
These sprouts were “[near]by sensory dorsal root ganglion (DRG) neurons”. These are the cells that cause so much sciatica pain. Nerve Sprouts, with blood supply, have been recently shown to form a membrane near this dorsal nerve ganglion ,this pain sensitive nerve centre. This ganglion resides in the foramen (hole) where the spinal nerves exit. This finding supplements my feeling that much chronic pain is related to neurovascular membranes “fuzz” that grows on tendons (see prior blog writeup), in the “high intensity zone” of damaged discs, and also near the “sciatica” nerve roots.
re this see:
Nerve Sprouts Seen in Chronic Back Pain Near Dorsal Ganglion
Surg Technol Int. 2006;15:243-56.
In-vivo endoscopic visualization of patho-anatomy in painful degenerative conditions of the lumbar spine. Yeung AT, Yeung CA.
“Neo-angiogenesis and neurogenesis in the inflammatory membrane present in the foraminal triangle was a new finding not reported in traditional clinical studies” abstract here
(foraminal triangle is where the dorsal ganglion resides)
ACE inhibitor stops sprouts:
In first study, Enalapril, a ACE inhibitor used in Blood pressure control, stopped the nerve sprouting in this mouse model.
However, one article found in Hypertensives, Enalapril made patients as pain sensitive as normal BP patients (ie. high blood pressure was associated with better pain tolerance but this disappearred once normotensive on Enalapril)
abstract here
ACE inhibitors are used to prevent migraines but never has the implication made that it might prevent chronic sciatica. Someone should do a study…
Off topic,
while researching enalapril I found it might help get rid of surgical scars:
Enalapril helps overactive surgical scars:
MedGenMed. 2006 Dec 20;8(4):60.
Low-dose enalapril in the treatment of surgical cutaneous hypertrophic scar and keloid–two case reports and literature review. Iannello S, Milazzo P, Bordonaro F, Belfiore F.article here
they used 10 mg/day.
Am interested in any thoughts…