Abstract
The relationship between sympathetic neural activity and blood pressure was examined for 167 women living in a rural area in Hyogo Prefecture, under ordinary conditions. In this study, serum Dopamine-beta-hydroxylase (DBH) activity and urinary noradrenaline/creatinine (NA/cr) ratio were used as the indices of sympathetic neural activity.
The results obtained are as follows:
1. No significant correlation was observed between serum DBH activity and urinary NA/cr. However, several different subgroups were included in the subjects examined, particularly among the age group of 40-49, one whose urinary NA/cr correlated positively to serum DBH activity and the others without this correlation.
2. The relation of serum DBH activity or urinary NA/cr to blood pressure was not clear when the factors were examined independently for the subjects as a whole.
3. However, when the same subjects were subdivided based on the 33 and 66 percentile values of serum DBH activity and urinary NA/cr and respective blood pressure levels were compared, blood pressure tended to increase with urinary NA/cr in the group with a moderate DBH activity level (20-40 IU).
4. In the subgroup selected from a scatter diagram of serum DBH activity and urinary NA/cr, which fell within±1 standard deviation from the regression line, systolic and diastolic blood pressure increased as serum DBH activity or urinary NA/cr increased. These relations were observed for all age groups.
The results suggest that sympathetic neural activity causally affects blood pressure level in some subjects.
