The effects of intracerebroventricular administration of renin on drinking and blood pressure.
The aim of the present investigation was to (a) determine if renin-substrate (angiotensinogen) is present in cerebrospinal fluid; (b) investigate the effects of intracerebroventricular administration of renin on drinking and blood pressure; and (c) determine if such effects are mediated via the formation of angiotensin II. Angiotensinogen concentration in cerebrospinal fluid was measured in 15 dogs and averaged 205 +/- 34 ng/ml. This value was approximately 1/5th of the corresponding plasma angiotensinogen concentration but the ratio of angiotensinogen:total protein in cerebrospinal fluid was approximately 15 times greater than in plasma. Intraventricular injection of hog renin (0.1 Goldblatt units) stimulated drinking in each of 8 dogs; the mean volume drunk in the 15 min period following the injection was 485 +/- 84 ml. When the renin was preceded by intraventricular saralasin acetate, a specific antagonist of angiotensin II, the drinking response was reduced to 8 +/- 6 ml. In eight pentobarbital anesthetized dogs, intraventricular dog or hog renin (0.05-0.25 Goldblatt units) increased systolic pressure from 152 +/- 10 to 168 +/- 10 mm Hg (P less than 0.001) and diastolic pressure from 101 +/- 8 to 116 +/- 7 mm Hg (P less than 0.001). This response, which lasted from 30 min to more than 3 h, was also abolished by saralasin acetate. These data indicate that centrally administered renin increases drinking and blood pressure and that these effects are mediated via the formation of angiotensin II.
D000804:Angiotensin II / Q000031:analogs & derivatives*; D000808:Angiotensinogen / Q000134:cerebrospinal fluid / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004285:Dogs; D004326:Drinking / Q000187:drug effects*; D005260:Female; D008297:Male; D012083:Renin / Q000134:cerebrospinal fluid / Q000494:pharmacology*
D000808:Angiotensinogen; D000804:Angiotensin II; D012083:Renin