3H-norepinephrine release in caudal artery of spontaneously hypertensive and Wistar-Kyoto rats: effects of altered salt diets.
The potassium-induced release of 3H-norepinephrine (3H-NE) was examined in the rat caudal artery. A simple and reliable method was developed to examine stimulated neurotransmitter release from this highly innervated resistance vessel. The potassium-induced release of 3H-NE was dose- and calcium-dependent. Stimulated 3H-NE release was elevated in the spontaneously hypertensive (SHR) compared to age-matched Wistar-Kyoto (WKY) animals (p less than 0.05). However, in animals at 5-6 weeks of age, where the blood pressure was not different between the SHR and WKY, the stimulation-induced release of 3H-NE was also not significantly different. Low salt diets for 7 days significantly decreased the potassium-induced release of 3H-NE from both 10- to 11-week-old SHR and WKY animals. High salt diets did not significantly effect 3H-NE release, even though the high salt diets for 7 days significantly increased the blood pressure in the SHR. The results suggest that the caudal artery is a good model to study stimulation-induced transmitter release and that elevated 3H-NE release plays a role in the development of hypertension in the SHR. Low salt diets, which did not lower blood pressure, were shown to decrease 3H-NE release. High salt diets elevated the blood pressure in the SHR but had no significant effect on stimulated 3H-NE release.
Meldrum
M J
MJ
University of Florida, Department of Pharmacodynamics, JHMHC, Gainesville 32610.
Glenton
P
P
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000294:innervation*; D001794:Blood Pressure; D002118:Calcium / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012982:Sodium, Dietary / Q000494:pharmacology*; D009435:Synaptic Transmission; D013623:Tail / Q000098:blood supply; D014316:Tritium
D012982:Sodium, Dietary; D014316:Tritium; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine