whereas brief exposure to epinephrine or bt2camp does not significantly affect the total number of cellular beta 2ars ( assessed by ligand binding ) , continued exposure results in a gradual decline in beta 2ar number to approximately 20 % ( epinephrine ) or approximately 45 % ( bt2camp ) of the levels in control cells by 24 hr .
C1517880
ligand binding
C0001643
beta 2ar