pretreatment of the atria with clonidine noncompetitively antagonized ( 10 ( -6 ) -- 10 ( -4 ) m ) the positive chronotropic actions of isoproterenol , and competitively antagonized ( 10 ( -4 ) m ) the negative chronotropic actions of pilocarpine .
C1372804
positive chronotropic
C0022245
isoproterenol