Angiotensin receptors in an Australian marsupial, the brushtail possum Trichosurus vulpecula

Sernia, C, Lello, P and Thomas, WG (1990) Angiotensin receptors in an Australian marsupial, the brushtail possum Trichosurus vulpecula. General and Comparative Endocrinology, 77 1: 116-126. doi:10.1016/0016-6480(90)90212-5


Author Sernia, C
Lello, P
Thomas, WG
Title Angiotensin receptors in an Australian marsupial, the brushtail possum Trichosurus vulpecula
Journal name General and Comparative Endocrinology   Check publisher's open access policy
ISSN 1095-6840
Publication date 1990-01-01
Sub-type Article (original research)
DOI 10.1016/0016-6480(90)90212-5
Volume 77
Issue 1
Start page 116
End page 126
Total pages 11
Language eng
Subject 1310 Endocrinology
Abstract In this study, the binding properties of angiotensin receptors were examined in the liver, adrenal, brain, and vascular tissue of the brushtail possum, Trichosurus vulpecula. With 125I-Ile5-angiotensin II as the radioligand, the binding affinity (Ka) and receptor number (R0) were estimated for the liver (Ka = 3.60 ± 0.31 liters/nmol; R0 = 23.8 ± 1.30 pmol/g tissue; n = 8) and adrenal (Ka = 1.68 ± 0.29 liters/nmol; R0 = 1.67 ± 0.23 pmol/g tissue; n = 8). Specific binding was not found in any of seven areas of the possum brain (n = 6), whereas the expected binding was present in similar areas of the rat brain. Using angiotensin III or the antagonist Sar1-Ala8-angiotensin II as radioligands or changing the composition of the incubation buffer did not alter the outcome. Moreover, the intracerebroventricular injection of 1 and 5 nmol of angiotensin II did not elicit an increase in blood pressure which could be attributed to brain angiotensin II (AII) receptors. Ligand affinities of the adrenal and liver receptors were found to be in the following decreasing order: Val5-AII > Ile5-AII = Ile5-AIII > Sar1-Ala8-AII > Sar1-Gly8-AII > Sar1-Leu8-AII > Ile5-AI > hexapeptide > Phe3-Tyr8-AII. The cardiovascular All receptor was investigated by generating dose-response curves of the pressor activity of Ile5-AII and six AII analogs infused intravenously. It was concluded that liver, adrenal, and vascular AII receptors in the marsupial possum have characteristics similar to those in eutherian mammals. However, the failure to find brain AII receptors raises the possibility that those functions mediated by such receptors in the eutherian brain are absent in the possum and perhaps other marsupials.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
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