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Biomedical subjects

K Kamoi

Publications and source records attributed to K Kamoi.

At least 145 records · Page 8Linked to original sources
PubMed1980

Effects of intraventricular injection of Sar1-Ala8-angiotensin II on plasma vasopressin level increased by angiotensin II and by water deprivation in conscious rats.

The effects of intraventricular injection of Sar1-Ala8-angiotensin II (A specific antagonist of angiotensin II) on the plasma vasopressin level increased by intraventricular injection of angiotensin II and by water deprivation (46 h) were examined in conscious male rats with an indwelling cannula in the third cerebral ventricle. Blood samplings were made by decapitation and the plasma level of vasopressin was determined by radioimmunoassay. Twenty-five, 50 or 100 ng of angiotensin II produced significant (P less than 0.05) increase in plasma vasopressin level 90 sec after the injection. The effect of 50 ng of angiotensin II was inhibited significantly (P less than 0.05) at least with 100 ng of Sar1-Ala8-angiotensin II given 2 min before the injection of angiotensin II. The dehydrated rats to which 1000 ng of Sar1-Ala8-angiotensin II was given 5 min before the decapitation showed the significantly (P less than 0.05) lower median plasma vasopressin level than that of the dehydrated controls. No significant difference in plasma osmolality was noted between them. These results suggest that the plasma vasopressin response to intraventricular angiotensin II is produced via angiotensin II receptors in the brain and that Sar1-Ala8-angiotensin II inhibits the effect of endogenous angiotensin II on plasma vasopressin level under dehydration.

Angiotensin II↗
PubMed1979

[A comparison between the effects of angiotensin II and angiotensin III injected into the third cerebral ventricle on vasopressin secretion in conscious rats (author's transl)].

As the greater part of the immunoreactive angiotensin II in cerebrospinal fluid has been suggested to be angiotensin III, a comparison was made between the effects on vasopressin release of angiotensin II and angiotensin III administered into the third cerebral ventricle in conscious male rats. The blood samples were collected 90 seconds after the injection of angiotensin II or angiotensin III by means of decapitation. Plasma vasopressin (microU/ml) extracted and determined by radioimmunoassay were 2.3 +/- 0.8, 6.7 +/- 5.0, 14.0 +/- 2.2, 16.3 +/- 4.3 and 20.7 +/- 2.5 (mean +/- SEM), respectively following the injection of 0, 10, 25, 50 and 100ng of angiotensin II. The increases in plasma vasopressin produced by angiotensin II 25, 50 and 100ng were statistically significant (p less than 0.05). On the other hand, plasma vasopressin following the injection of 22.7 and 45.4ng of angiotensin III, which are equimolar to 25 and 50ng of angiotensin II each, were 14.9 +/- 2.7 and 16.3 +/- 5.6, respectively. No significant difference was found between the effect on plasma vasopressin of angiotensin II and that of angiotensin III at the dose level of 24.3 or 48.6 p. mol. These data indicate that angiotensin III is equipotent to angiotensin II in terms of vasopressin release when administered into the third cerebral ventricle. The possible role of angiotensin III in the brain on vasopressin secretion is discussed.

Angiotensin II↗