these findings suggest that the postjunctional adrenoceptors present in the sarcolemma of the isolated cardiac muscle cells , which mediate automaticity responses to catecholamines , are of beta 1 , beta 2 , and alpha 1 types , the physiological contribution of the beta 1-adrenoceptors being predominant .
C0034783
adrenoceptors
C0001642
beta 1-adrenoceptors