Date of Award
Doctor of Philosophy in Pharmaceutical Sciences
John J. DeFeo
The relationship among urinary dopamine levels, arterial blood pressure and kidney monoanine oxidane activity was studied in hypertensive rats.
The rats were rendered hypertensive by two operations: right nephrectomy followed in two weeks by contralateral renal arterial compression.
The blood pressures rose steadily throughout the first 11 weeks following the second operation and at the end of this period leveled off at approximately 180-185 mm Hg.
Dopamine was extracted from pooled urine samples by ion exchange techniques and measured by spectrofluorimetric methods.
Dopamine levels (means from pooled group data) rose throughout the experimental period from a control value of 675 ± 166 μg/1 to 1022 ± 449 μg/1. The rising pattern of dopamine was interrupted by sharp decreases during the eleventh and thirteenth weeks.
A linear correlation, excluding control values and values from the last week of the investigation, was conducted by regressing blood pressure on logarithm dopamine concentration. The analysis which was valid only for dopamine concentration ranging from 500-1000 μg/1 resulted in a regression coefficient of 0.85 and a coefficient of determination of 0.72 indicating a fair degree of linear association between the two variables.
Monoamine oxidase activity dropped off sharply following the second operation, went through what appeared to be a compensatory rise, and then decreased to 40 percent of its original activity at the end of the investigational period.
In considering the interrelationship among the three variables, a definite correlation between dopamine and the blood pressure was shown to exist, however, a clear relationship between dopamine and monoamine oxidase inhibition was not established.
De Fanti, David Rockwell, "The Relationship of Dopamine to Blood Pressure and Monoamine Oxidase Activity in Hypertensive Rats" (1961). Open Access Dissertations. Paper 495.