methacholine was used as an agonist to decrease the stimulation-evoked overflow of either endogenous noradrenaline ( rabbit heart ) or previously incorporated 3h-noradrenaline ( rat heart ) by a presynaptic muscarine receptor mechanism , and to reduce the atrial tension development of either the spontaneously beating perfused rabbit heart or incubated rat left atria paced at 2 hz ( postsynaptic effect ) .
C0018787
heart
C0225860
left atria