Angiotensin (Ang) II and atrial natriuretic peptide (ANP) have opposing effects on blood pressure, sympathetic activity, vasopressin and ACTH secretion, salt appetite, and drinking. We observed their interaction by infusing Ang II (7.2 nmol/h) into the peritoneum (ip) or into the lateral ventricle (icv) of rats with osmotic minipumps for seven days. At sacrifice, rats receiving Ang II-icv had a systolic blood pressure of 184±3 (SEM) mmHg, those receiving Ang Il-ip had 159±5 niniHg (p<0.05), while controls had 109±2 and 110±2 mmHg, respectively (p<0.05). Drinking and urine volume increased similarly in rats receiving Ang II by either route, while Uosm decreased. Renin (PRA) values were lower (p<0.05) in rats receiving Ang II-icv (0.7±0.2 ng Ang 1/ml/h) or Ang Il-ip (0.9±0.2) than in the respective controls (2.3±0.7 and 2.0±0.3). Plasma ANP values with Ang II-icv (18±1.6 pg/ml) or with Ang Il-ip (49 ±6) were also lower (p<0.05) than respective controls (89±12, 76 ±4). Vasopressin (AVP) concentrations in the plasma were not influenced by the regimens. In the brain, the ANP contents in areas of the so-called AV3V-region (organum vasculosum laminae terminalis, preoptic periventricular nucleus, medial preoptic nucleus) were similarly and significantly reduced by both Ang II-icv and Ang Il-ip. ANP values were also reduced in the median eminence by both types of Ang H-treatment, while ANP concentrations in the supraoptic nucleus were increased. The data show that Ang II infusions producing a chronic rise in blood pressure exert similar effects on drinking behavior, PR A, and ANP concentrations in blood and brain. The AV3V area may be pivotal to both models. (Hypertens Res 1995; 18: 279-284).
- Angiotensin II
- atrial natriuretic peptide
ASJC Scopus subject areas
- Internal Medicine
- Cardiology and Cardiovascular Medicine