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.

No abstract

Endogenous noradrenaline and 3,4-dihydroxyphenylethylamine (dopamine) levels were measured in different zones of the dog kidney following chronic unilateral renal denervation. In outer and inner renal cortex, and in outer medulla, >95% of the tissue content of both catecholamines was contributed by renal nerves, whereas in inner medulla only nonneuronal catechol-amines were found. The amounts of neuronal dopamine present in outer renal cortex were greater than would be expected for a population of solely noradrenergic nerves. Key Words: Noradrenaline-Dopamine-Renal nerves -Kidney. Petrovic T. et al. Neuronal and nonneuronal contributions to renal catecholamine content in the dog. Abbreviations used: DA, 3,4-dihydroxyphenylethylamine (dopamine); DOPA, 3,4-dihydroxyphenylalanine; NA, noradrenaline.

We describe the design and development of a highly interactive model-building program to assist students from a diverse range of academic backgrounds to understand the baroreceptor reflex. Our approach is to have students work in small groups to construct their own simple model of such a control system. This model then provides the basis for a structural framework for students to add further complexity without losing overall perspective and allows exploration of deeper issues. Our program is suitable for many disciplines and student backgrounds and provides a visual representation of a difficult concept, providing a basis to ground further knowledge. Audit trail data have been analyzed to identify and resolve areas of student difficulty, and extensive surveys and observations on students' use of the program over three years in several courses have been used to test and improve its effectiveness.

No abstract