there are also 2 principal subtypes of beta-adrenoceptors . beta 1-receptors have a high affinity for both noradrenaline and adrenaline ( epinephrine ) and are found in the heart , brain , and adipose tissue . beta 2-receptors have a low affinity for noradrenaline and are involved in mediation of relaxation of vascular and other smooth muscles and in many of the metabolic effects of catecholamines .
C0014563
epinephrine
C0028351
noradrenaline