TY - JOUR
T1 - Relationship between sodium balance and renal innervation during hypertension development in the spontaneously hypertensive rat
AU - Greenberg, Suzanne
AU - Osborn, Jeffrey L.
PY - 1994/12
Y1 - 1994/12
N2 - Introduction: The spontaneously hypertensive rat (SHR) has been shown to possess elevated efferent sympathetic nerve activity, and renal denervation delays the development of hypertension in this genetic strain. Evidence that the renal sympathetic nerves have direct effects on tubular function suggests that one of the mechanisms for increasing arterial pressure in the SHR might involve neurally mediated sodium retention. Aims and methods: The present study examined the relationships between renal sympathetic tone, daily sodium balance and the development of hypertension in SHR over a 4-week period. Conscious, unrestrained, 7-week-old SHR with innervated or denervated kidneys were placed on a fixed sodium intake by intravenous infusion (5.72 μmol/day per 100 g body weight). Urinary sodium excretion was determined once a day for 28 consecutive days; systolic blood pressure (SBP) and body weight were monitored twice a week. Results: Renal denervation delayed the onset of and retarded the development of hypertension. Despite the difference in SBP, daily sodium balance was equal in the innervated and the denervated SHR. The positive sodium balances exhibited by both groups are attributed to the rapid growth observed during the time course of the experiment. The growth rate was also similar in the two groups. Conclusion: The present data indicate that, although the renal nerves may mediate enhanced transient tubular sodium reabsorption, sodium retention does not contribute directly to the development of hypertension in the SHR. Rather, it appears that the elevation of arterial pressure might occur as a requirement to excrete excess sodium and thus maintain a daily sodium balance.
AB - Introduction: The spontaneously hypertensive rat (SHR) has been shown to possess elevated efferent sympathetic nerve activity, and renal denervation delays the development of hypertension in this genetic strain. Evidence that the renal sympathetic nerves have direct effects on tubular function suggests that one of the mechanisms for increasing arterial pressure in the SHR might involve neurally mediated sodium retention. Aims and methods: The present study examined the relationships between renal sympathetic tone, daily sodium balance and the development of hypertension in SHR over a 4-week period. Conscious, unrestrained, 7-week-old SHR with innervated or denervated kidneys were placed on a fixed sodium intake by intravenous infusion (5.72 μmol/day per 100 g body weight). Urinary sodium excretion was determined once a day for 28 consecutive days; systolic blood pressure (SBP) and body weight were monitored twice a week. Results: Renal denervation delayed the onset of and retarded the development of hypertension. Despite the difference in SBP, daily sodium balance was equal in the innervated and the denervated SHR. The positive sodium balances exhibited by both groups are attributed to the rapid growth observed during the time course of the experiment. The growth rate was also similar in the two groups. Conclusion: The present data indicate that, although the renal nerves may mediate enhanced transient tubular sodium reabsorption, sodium retention does not contribute directly to the development of hypertension in the SHR. Rather, it appears that the elevation of arterial pressure might occur as a requirement to excrete excess sodium and thus maintain a daily sodium balance.
KW - Renal hypertension
KW - Sodium chloride
KW - Water-electrolyte balance
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U2 - 10.1097/00004872-199412000-00007
DO - 10.1097/00004872-199412000-00007
M3 - Article
C2 - 7706694
AN - SCOPUS:0028586803
SN - 0263-6352
VL - 12
SP - 1359
EP - 1364
JO - Journal of Hypertension
JF - Journal of Hypertension
IS - 12
ER -