17 beta-Estradiol inhibits carotid sinus baroreceptor activity in anesthetized male rats.
OBJECTIVE
To study the effect of 17beta-estradiol (E2) on carotid baroreceptor activity (CBA).


METHODS
The functional curve of carotid baroreceptor (FCCB) was constructed and the functional parameters of carotid baroreceptor were measured by recording sinus nerve afferent discharge in anesthetized male rats with perfused isolated carotid sinus.


RESULTS
E2 3, 10, and 30 micromol/L shifted FCCB to the right and downward, with a marked decrease in peak slope (PS) and peak integral value of carotid sinus nerve discharge (PIV) in a concentration-dependent manner, indicating the inhibitory effect of E2 on CBA. Pretreatment with tamoxifen (TAM) 10 micromol/L, an inhibitor of estrogen receptor, did not block the effect of E2 on CBA. Preperfusion with L-NAME 100 micromol/L, an inhibitor of NO synthase, could completely abolish the effect of E2 on CBA. NO donor SIN-1 10 micromol/L could potentiate the inhibitory effect of E2.


CONCLUSIONS
E2 inhibits CBA via endothelial NO release.
Wang
S
S
Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017, China.
Fan
Z Z
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He
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D000758:Anesthesia; D000818:Animals; D002346:Carotid Sinus / Q000187:drug effects* / Q000502:physiology; D004958:Estradiol / Q000494:pharmacology*; D008297:Male; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011311:Pressoreceptors / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors; D013629:Tamoxifen / Q000494:pharmacology
D020030:Nitric Oxide Donors; D011960:Receptors, Estrogen; D013629:Tamoxifen; D004958:Estradiol; C002385:linsidomine; D008981:Molsidomine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester