Potassium feeding reduces hyperactive central nervous system pressor responses in Dahl salt-sensitive rats.
Dahl showed that feeding KCl prevents the rise in blood pressure caused by a high NaCl diet in salt-sensitive Dahl "S" rats. Such S rats when normotensive on a low NaCl diet have a 2 to 3 times greater pressor response than Dahl "R" rats to intracerebroventricular hypertonic saline (600 mOsm/liter) or angiotensin II (AII) (500 ng). Does dietary KCl prevent NaCl hypertension in S rats partly by abolishing these hyperactive central nervous system (CNS) pressor responses? The effect of potassium-loading on CNS pressor responses was studied in S rats on a low (0.3%) NaCl diet. Drinking a 2% KCl solution reduced the CNS pressor responses in S rats to both AII and hypertonic saline by 44% (p less than 0.025) and brought them down almost as low as in R rats. KCl added to the low NaCl dry diet also decreased the CNS pressor responses in S rats to AII and to hypertonic saline by 39% (p less than 0.01) and 59% (p less than 0.02) respectively. K-citrate added to the low NaCl diet was generally as effective as KCl in reducing CNS pressor responses. K-citrate reduced the angiotensin pressor response by 44% (p less than 0.001) and the hypertonic saline pressor response by 46% (p less than 0.05). Thus, potassium feeding greatly diminished the hyperactive CNS pressor responses in S rats. This CNS action may well explain a good part of the protective effect of KCl against NaCl hypertension in S rats.
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000502:physiology*; D004032:Diet; D008297:Male; D011188:Potassium / Q000494:pharmacology*; D011311:Pressoreceptors / Q000502:physiology; D051381:Rats; D012965:Sodium Chloride / Q000494:pharmacology*
D000804:Angiotensin II; D012965:Sodium Chloride; D011188:Potassium