Ginkgolide B inhibits carotid sinus baroreflex in anesthetized male rats.
The effects of ginkgolide B on the carotid sinus baroreflex (CSB) were studied in the perfused isolated carotid sinus of 30 anesthetized Sprague-Dawley male rats. The results were as follows. (1) By perfusing with ginkgolide B (0.1, 1, 10 μmol/L), the functional curve of the baroreflex was shifted to the right and upward. There was a marked decrease in peak slope (PS) and reflex decrease (RD) in mean arterial pressure (P<0.01), while the threshold pressure (TP), equilibrium pressure (EP) and saturation pressure (SP) were significantly increased (P<0.05, P<0.01). Among the functional parameters of CSB, the changes in PS, RD, TP, EP and SP were dose-dependent. (2) Pretreatment with Bay K8644 (500 nmol/L), an agonist of L-type calcium channel, completely eliminated the effects of ginkgolide B (1 μmol/L) on the CSB. (3) Pretreatment with tetraethylammonium (TEA, 1 mmol/L), an inhibitor of potassium channel, completely abolished the above effects of ginkgolide B (1 μmol/L) on the CSB. These results suggest that ginkgolide B inhibits the CSB in anesthetized rats, which is mediated by decreased calcium influx and increased potassium efflux in baroreceptor nerve endings.
Wang
Chun-Yan
CY
Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017, China.
Wu
Yu-Ming
YM
Xiao
Lin
L
Xue
Hong-Mei
HM
Wang
Ru
R
Wang
Fu-Wei
FW
He
Rui-Rong
RR
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D017704:Baroreflex / Q000187:drug effects*; D002120:Calcium Channel Agonists / Q000494:pharmacology; D020746:Calcium Channels, L-Type; D002346:Carotid Sinus / Q000503:physiopathology*; D046934:Ginkgolides / Q000494:pharmacology*; D007783:Lactones / Q000494:pharmacology*; D008297:Male; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011311:Pressoreceptors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019789:Tetraethylammonium / Q000494:pharmacology
D002120:Calcium Channel Agonists; D020746:Calcium Channels, L-Type; D046934:Ginkgolides; D007783:Lactones; D026902:Potassium Channel Blockers; D019789:Tetraethylammonium; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; C045856:ginkgolide B