Neurotrophic Abnormalities and Development of High Blood Pressure in Genetically Hypertensive Rats

• Inbred strains ofWistar rats that spontaneously develop high blood pressure are used commonly as models of essential hypertension. In two of these strains, the spontaneously hypertensive rat and the genetically hypertensive rat, there is evidence for peripheral neurotrophic abnormalities. In the spontaneously hypertensive rat, there is elevated production of nerve growth factor, but the numbers of sympathetic and sensory neurons suggest that there may also be abnormal availability of some other neurotrophins early in development. In the genetically hypertensive rats, there is apparent decreased sympathetic access to and increased sensory access to nerve growth factor. In neither case is it clear whether or not there is any causal relationship between the neurotrophic abnormality and genesis of elevated blood pressure. The mechanistic relevance of the spontaneously hypertensive rats or the genetically hypertensive rats to the clinical syndrome of essential hypertension is similarly uncertain. However, both of these strains constitute interesting and potentially valuable systems for studying the neurotrophic regulation of normal development.