Estrogen-sensitive projections from the medial preoptic area to the dorsal pontine tegmentum, including Barrington's nucleus, in the rat.
OBJECTIVE
Urinary incontinence affects a significant number of post-menopausal women. There is conflicting evidence whether voiding symptoms in these women are related to hypoestrogenism or aging itself. This neuroanatomical study was designed to determine whether a specific central nervous system (CNS) pathway that projects to the pontine micturition center (PMC, also known as "Barrington's nucleus") is estrogen sensitive in a rat model.


METHODS
A fluorescent retrograde tracer was injected into the dorsal pontine tegmentum of adult female Sprague-Dawley rats to identify neurons in the medial preoptic area (MPA) that project to the PMC. Immunohistochemistry was performed using antibodies directed against estrogen receptor-alpha (ERalpha) and estrogen receptor-beta (ERbeta) to identify estrogen-sensitive neurons. The brain sections were examined using fluorescence microscopy to identify cells that project to the PMC (contain fluorescent tracer) and also express ER (are immunoreactive for ER).


RESULTS
There are neurons in the MPA that are double labeled (contain fluorescent tracer and express ERalpha, but not ERbeta), showing that a subset of neurons projecting from the MPA to the PMC is estrogen sensitive.


CONCLUSIONS
A subset of estrogen-sensitive neurons projects from the MPA to the PMC in rats, raising the possibility that indirect estrogenic regulation of forebrain neuronal function may modulate the micturition reflex. Future development of drugs that alter the function of this estrogen-sensitive CNS pathway may provide therapeutic strategies to treat post-menopausal incontinence.
Rickey
Leslie Minor
LM
Division of Urology, University of Maryland Medical Center, Baltimore, Maryland 21201, USA. lrickey@smail.umaryland.edu
Sarkey
Sara
S
DonCarlos
Lydia L
LL
D000818:Animals; D003627:Data Interpretation, Statistical; D047628:Estrogen Receptor alpha / Q000187:drug effects / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000187:drug effects / Q000378:metabolism; D004967:Estrogens / Q000502:physiology*; D005260:Female; D005456:Fluorescent Dyes; D008125:Locus Coeruleus / Q000502:physiology*; D008856:Microscopy, Fluorescence; D009434:Neural Pathways / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D010052:Ovariectomy; D011149:Pons / Q000502:physiology*; D011301:Preoptic Area / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013266:Stilbamidines
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D005456:Fluorescent Dyes; D013266:Stilbamidines