简介：ObjectivesToinvestigatetheeffectsofadrenergicreceptorantagonist(metoprololorprazosin)onmyocardialα1-ARdensityandthechangesofventriculareffectiverefractoryperioddispersion(VERP-D)inrabbitsaftermyocardialinfarction.Methodstwenty-fouradultmaleNewZealandrabbitsweredividedintofourgroupsatrandom:controlgroup(n=6);MIwithplacebogroup(n=6);MIwithmetoprololgroup(n=6);MIwithprazosingroup(n=6).Therabbitsreceivedcorrespondingdrugsforsevendays,beginningatthefirstdayafterMIandmyocardialα1-ARdensityweremeasuredandmeanwhile,myocardialβ-ARwasalsomeasured.ResultsIntheplacebogroup,thedensityofventricularα1-ARwasincreasedincomparisonwithcontrolgroup(α1-ARinnormalregion36.9±0.2vs27.3±0.9fmolmg-1Pro-1,p＜0.01;α1-ARinischemicregion33.0±0.9vs26.6±0.4fmolmg-1pro-1P＜0.01).Inthemetoprololgroup,itwasalsoincreasedincomparisonwithcontrolgroup(α1-ARinnormalregion44.7±1.5vs27.3±0.9fmolmg-1pro-1,P＜0.01;α1-ARinischemicregion33.6±0.5vs26.6±0.4fmolmg-1pro-1,P＜0.01).Meanwhilethedensityofventricularα1-ARinnormalregioninthemetoprololgroupwasincreasedincomparisonwithplacebogroup(44.7±1.5vs36.9±0.2fmolmg-1pro-1,P＜0.01).Whileitdecreasedintheprazosingroupincomparisonwithcontrolgroup(α1-ARinnormalregion22.5±0.6vs27.3±0.9fmolmg-1pro-1,P＜0.01;α1-ARinischemicregion20.9±0.4vs26.6±0.4fmolmg-1pro-1,P＜0.01).VERP-DwasincreasedafterMI(P＜0.01).Aftertreatmentwithmetoprololorprazosin,VERP-Dwasdecreased(P＜0.01).ConclusionsAfteracuteMI,α1-ARofventricularmyocardiumwasupregulated,whichmaybeaccompaniedbyitsactivitation.Thedensityofmyocardialα1-ARbecameupregulatedmoredramaticallytreatedwithmetoprololanddownregulatedwithprazosin.Whentreatedwithmetoprololorprazosin,VERP-Ddecreased.

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