Decreased concentration of myocardial alpha-adrenoceptors with increasing age in foetal lambs.
Using [3H]-dihydroergocryptine, we identified myocardial alpha-adrenoceptor binding sites in foetal lambs and demonstrated that the concentration of receptors decreased with increasing foetal age. The presence of the receptor in the foetus correlated with the presence of myocardial alpha-adrenergic responsiveness. However, we found neither the alpha-receptor binding site nor responsiveness to alpha-adrenoceptor stimulation in the myocardium of adult sheep.
D000818:Animals; D001665:Binding Sites; D005260:Female; D005318:Fetal Heart / Q000032:analysis*; D005865:Gestational Age; D009200:Myocardial Contraction / Q000187:drug effects; D011247:Pregnancy; D011941:Receptors, Adrenergic / Q000032:analysis*; D011942:Receptors, Adrenergic, alpha / Q000032:analysis*; D011943:Receptors, Adrenergic, beta / Q000032:analysis; D012756:Sheep
D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta