Hypertension, Vol 8, 122-127, Copyright © 1986 by American Heart Association
Catecholamines in kidneys of normotensive and genetically hypertensive rats. Effects of salt load
T Petrovic and C Bell
The tissue content of norepinephrine, dopamine, and epinephrine was
determined in different zones of the kidney in normotensive Sprague- Dawley
and Otago Wistar rats and in genetically hypertensive Otago Wistar rats.
One kidney in each animal was chronically denervated to allow estimation of
the neuronal contribution to renal catecholamine content. In all strains,
the renal cortex contained negligible amounts of nonneuronal norepinephrine
and dopamine, while outer and inner medullary layers contained
progressively larger amounts. Nonneuronal epinephrine was distributed
fairly evenly through cortex and medulla. Neuronal norepinephrine content
was similar in inner and outer cortex, substantially less in outer medulla,
and not discernible in inner medulla. The amounts of neuronal dopamine were
consistent with its localization predominantly in noradrenergic nerves. The
renal cortices of normotensive Wistar rats contained more neuronal
norepinephrine and less neuronal dopamine than those of Sprague-Dawley
rats, and the cortices of hypertensive Wistar rats contained slightly more
norepinephrine than those of normotensive Wistar rats. In both normotensive
strains, long-term salt loading decreased selectively the neuronal
norepinephrine in renal cortex. By contrast, in hypertensive animals,
cortical norepinephrine was not reduced by salt loading. These results
indicate that the genetically hypertensive rat may have an abnormal
sympathetic reflex response to increased blood volume.