thus , when catecholamines , histamine and adenosine are released together , as in myocardial ischemia , in addition to their individual effects , negative inotropism , decreased impulse conduction velocity and coronary constriction ( i.e. , h1- and alpha-mediated responses ) may result from the adenosine-histamine-norepinephrine interaction .
C0007412
catecholamines
C0028351
norepinephrine