Renal catecholamines and alpha 2-adrenergic receptors in salt-related and genetic hypertension.
Increased dietary salt intake alters renal function which often leads to deleterious cardiovascular consequences. Studies were carried out to characterize the effects of high-salt diets on renal catecholamines and alpha 2-adrenergic receptors. These parameters were evaluated in both genetic and acquired forms of hypertension and also in normotensive rats on high-salt diets. Renal catecholamine content was determined by high-performance liquid chromatography with electrochemical detection. Renal alpha 2-adrenergic receptor-binding studies were performed on whole kidney homogenates using 3H-p-aminoclonidine to label both high- (0.5 nM) and low-affinity (5.0 nM) renal alpha 2-adrenergic receptors. Increased salt intake elevated blood pressure, decreased renal norepinephrine stores and resulted in renal alpha 2-adrenergic receptor up-regulation in deoxycorticosterone acetate salt hypertensive rats, Dahl-S rats and COX-SHR. The decreased renal stores of norepinephrine (NE) appeared to reflect increased renal NE utilization. In contrast, SHR (Charles River) had elevated NE stores and alpha 2-adrenergic receptors while on normal salt diets. Short-term (10-14 days) exposure to high-salt diets had modest effects in normotensive rats or COX-SHR, although it was sufficient to increase low affinity renal alpha 2-adrenergic receptor number. Renal dopamine metabolism was also altered by high-salt diets. These studies demonstrated a relationship between renal NE content and renal alpha 2-adrenergic receptors. The implications of this relationship and other salt-related changes in renal catecholamine metabolism were discussed as they pertained to hypertension and renal function.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002395:Catecholamines / Q000652:urine*; D003900:Desoxycorticosterone; D004298:Dopamine / Q000652:urine; D006973:Hypertension / Q000139:chemically induced / Q000235:genetics / Q000652:urine*; D006977:Hypertension, Renal / Q000652:urine; D009638:Norepinephrine / Q000652:urine; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D012965:Sodium Chloride
D002395:Catecholamines; D011942:Receptors, Adrenergic, alpha; D003900:Desoxycorticosterone; D012965:Sodium Chloride; D004298:Dopamine; D009638:Norepinephrine