Asymmetrical effect of captopril on the angiotensinase activity in frontal cortex and plasma of the spontaneously hypertensive rats: expanding the model of neuroendocrine integration.

There is a reciprocal connection between the frontal cortex (FC) and cardiovascular function, and this connection is functionally lateralized. The possible pathophysiological impact of neuroendocrine asymmetries is largely underestimated. Our aim was to examine the activity of soluble (SOL) and membrane-bound (MB) aminopeptidases (APs) involved in the renin-angiotensin system in the peripheral plasma and in the left and right FC, in both untreated (control) and captopril-treated spontaneously hypertensive rats (SHRs). Enzymatic activities were measured fluorometrically using arylamide derivatives as substrates. Captopril reduced systolic blood pressure, but no differences in plasma AP activity were observed between the control and treated SHRs. In contrast, whereas the bilateral pattern (left vs. right differences) of SOL activities did not substantially change in the FC after captopril treatment, the asymmetries observed for MB activities in the FC markedly increased compared with the control group. Moreover, correlations between the AP activities in the plasma and those in the left or right FC were observed. In the control rats, the plasma AP activities correlated significantly with those in the right FC, whereas they correlated with those in the left FC in the captopril-treated group. In both groups (control and captopril), these correlations were negative for the SOL activity but positive for the MB activity. The present results reveal a pattern of bilateral behavior between the nervous and cardiovascular systems. The inverted bilateral behavior after captopril treatment suggests a systematized, lateralized neuroendocrine response representing a regular bilateral behavior that has yet to be analyzed.
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