Reduced sympathetic neuronal uptake (uptake1) in a genetic model of desoxycorticosterone-NaCl hypertension.
The effect of desoxycorticosterone (DOC)-NaCl treatment upon sympathetic neuronal uptake of norepinephrine (uptake1) was evaluated in strains of hypertension-resistant (SBN) and -prone (SBH) rats. Uninephrectomized animals were given either a placebo pellet sc and tapwater (untreated) or a 25-mg DOC pellet and 1% NaCl. Four weeks later, tail systolic pressure was significantly higher in DOC-NaCl SBH, 183 +/- 3 mm Hg, than SBN, 141 +/- 2 (P less than 0.01). [3H]Norepinephrine (NE) uptake was determined in heart slices of all four groups by incubation in Krebs buffer at 37 degrees C for 20 min at several concentrations. Preliminary studies confirmed that this is a measure of uptake1. Heart slices of DOC-NaCl-treated SBN and SBH rats had significantly reduced NE uptake at concentrations of 10-80 nM (P less than 0.01); there was no significant difference between SBN and SBH in this regard. Untreated SBH rats have been shown to have a defect in baroreflex regulation when normotensive. The results raise the possibility that the greater increase in arterial pressure caused by DOC-NaCl in SBH compared to SBN may be related to both the inborn difference in reflex function and an acquired reduction in inactivation of norepinephrine by sympathetic neuronal uptake.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003900:Desoxycorticosterone / Q000494:pharmacology*; D004285:Dogs; D006801:Humans; D006973:Hypertension / Q000139:chemically induced / Q000235:genetics*; D009206:Myocardium / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000378:metabolism* / Q000503:physiopathology
D003900:Desoxycorticosterone; D012965:Sodium Chloride; D009638:Norepinephrine