Norepinephrine overflow and re-uptake in perfused mesenteric arteries of Dahl salt-sensitive and salt-resistant rats.
We compared the overflow of endogenous norepinephrine (NE) upon electrical stimulation, the associated pressor response and rate of initial neuronal uptake of 3H-I-NE in the perfused mesenteric arteries of Dahl salt-sensitive (DS) and salt-resistant (DR) rats on two dietary NaCl regimens (0.4 and 8.0% for 2 weeks) from 4 weeks of age. The tissues of two rats, a DS and a DR control, were simultaneously processed and subjected to the same electrical stimulation. The pressor response and overflow of endogenous NE during periarterial nerve stimulation (5, 10 Hz, 1 min) in the tissue of DS rats on a high-salt diet (HS) were significantly greater, while those of DS on a low-salt diet (LS) were moderately but significantly higher than those of DR rats on either a high (HR) or a low-salt diet (LR). The tissue content of NE in DS rats was significantly lower than DR groups. There was a significantly reduced 3H-I-NE uptake in the tissues of DS rats on both salt diet groups compared with DR rats. A submaximal dose of exogenous NE evoked a significantly greater pressor response amplitude in mesenteric tissues from DS rats on a high-salt diet than in any of the other three groups, suggesting that smooth muscle supersensitivity, either in the density of the NE receptor or in the excitation-contraction coupling system, had been induced in the vasculature of DS rats by feeding them on a high-salt diet for 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)
Hano
T
T
Department of Clinical Pharmacology, School of Medicine, University of Southern California, Los Angeles 90033.
Jeng
Y
Y
Rho
J
J
D000818:Animals; D003042:Cocaine / Q000502:physiology; D004558:Electric Stimulation; D006973:Hypertension / Q000209:etiology / Q000235:genetics / Q000378:metabolism*; D008638:Mesenteric Arteries / Q000294:innervation; D014179:Neurotransmitter Uptake Inhibitors; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012982:Sodium, Dietary / Q000009:adverse effects*; D014661:Vasoconstriction
D014179:Neurotransmitter Uptake Inhibitors; D012982:Sodium, Dietary; D003042:Cocaine; D009638:Norepinephrine