whereas 1 is a potent beta-adrenoceptor agonist in guinea pig atria and trachea ( pd2 = 8.2 ) , analogue 2 was marginally effective at relaxing guinea pig tracheal smooth muscle ( pd2 = 4.4 ) and inactive as an agonist on guinea pig atria .
C0040578
trachea
C1710458
tracheal smooth muscle