a direct involvement of beta 2-adrenoceptors became manifest by selectively antagonizing beta 1-adrenoceptors by 1- [ 2 [ 3-carbamoyl-4-hydroxy ) phenoxy ) ethylamino ] - 3- [ 4 ( 1-methyl-4-trifluoromethyl-2-imidazolyl ) phenoxy ] -2-propanol ( cgp 20712 a ) without affecting beta 2-adrenoceptor . beta 2-adrenoceptors can mediate half of the maximum increase of contractile force elicited by low concentrations of adrenaline and also contribute to the increase of contractile force caused by high concentrations of noradrenaline . beta-adrenoceptors were labelled in membrane particles with 3h- ( - ) -bupranolol in the absence ( beta 1 & beta 2 ) and presence of 500 nmol/l cgp 20712 a ( beta 2 ) .
C0014563
adrenaline
C0028351
noradrenaline