Differential ontogeny of alpha 1-adrenergic and cholinergic receptor sites in the atria and ventricles of the inbred Dahl hypertension-sensitive (S/JR) and -resistant (R/JR) rat.
The ontogeny of atrial and ventricular alpha 1-adrenergic and muscarinic cholinergic receptor sites was investigated in inbred Dahl hypertension-sensitive (S/JR) and -resistant (R/JR) rats between 5 and 150 days of age. The density of sites in both cardiac regions was generally greater in the neonate than mature rat. A marked proliferation of sites was observed in neonatal and young adult rats that occurred in the following order: ventricular cholinoceptors----ventricular adrenoceptors----atrial cholinoceptors----atrial adrenoceptors. The density of ventricular adrenoceptors was greater in the S/JR rat than the R/JR rat at 5 days of age. At 150 days of age, the density of sites was less in the S/JR rat than the age-matched R/JR rat or the normotensive 50-day-old S/JR rat. The development of atrial adrenoceptors was similar between the strains, regardless of the blood pressure. The density of ventricular cholinergic receptors was greater in the S/JR strain at 5 and 15 days of age. However, the density of atrial cholinergic sites was consistently greater in the S/JR strain throughout development. The results of this study suggest that: (1) significant prenatal receptor development occurs in the heart; (2) receptor development may precede the functional maturation of postganglionic autonomic efferents; and (3) distinguishing differences in the regional density of alpha 1-adrenergic and muscarinic cholinergic binding sites are present between S/JR and R/JR rats at much earlier points in development than previously shown.
McCaughran
J A
JA
Department of Psychiatry and Behavioral Sciences, State University of New York, Stony Brook 11794.
Juno
C J
CJ
O'Malley
E
E
D000818:Animals; D001665:Binding Sites; D005260:Female; D006321:Heart / Q000294:innervation*; D006325:Heart Atria / Q000294:innervation; D006352:Heart Ventricles / Q000294:innervation; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000502:physiology*
D011942:Receptors, Adrenergic, alpha; D011950:Receptors, Cholinergic; D011813:Quinuclidinyl Benzilate; D011224:Prazosin