A comparison of AT(1) angiotensin II antagonists at pre- and postjunctional angiotensin II receptors of the rat tall artery

• Type: Article in International Scientific Journal
• Date: 2002

Authors

Pinheiro, H (Author) Other; moura, d (Author) FMUP; Albino Teixeira, A (Author) FMUP; Alves, C (Author) Other; Torres, L (Author) Other; Guimaraes, S (Author) Other

Journal

Title: Naunyn-Schmiedeberg's Archives of Pharmacology

Vol. 366

Pages: 537-542

ISSN: 0028-1298

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 11 Citations

Scopus - 13 Citations

Other information

Authenticus ID: P-000-M9W

DOI: 10.1007/s00210-002-0645-8

Abstract (EN): A comparison was made of the influence of candesartan, ZD7155, losartan and eprosartan on angiotensin II effects at pre- and postjunctional. AT(1) receptors of the rat tail artery. To study the anti- angiotensin II effect at prejunctional receptors, the tissues were preincubated with [H-3]noradrenaline and then superfused and electrically stimulated (1 Hz, 2 ms, 50 mA, during 5 min); to study the angiotensin II effect at postjunctional receptors, non-cumulative concentration-response curves to angiotensin II were determined in the absence and in the presence of the antagonist. pA(2) values were calculated for competitive antagonists and pD'(2) values for insurmountable antagonists. At the prejunctional level, losartan and eprosartan displayed competitive antagonism with pA(2) values of 6.50 and 8.08, respectively, whereas candesartan and ZD7155 displayed non-competitive antagonism with pD'(2) values of 8.71 and 7.98, respectively. At the postjunctional level, the four antagonists displayed the same kind of antagonism as prejunctionally with pA(2) values for losartan and eprosartan of 8.52 and 8.22, respectively, and pD'(2) values of 10.62 and 9.01, for candesartan and ZD7155, respectively. The ratios between post- and prejunctional potencies were: losartan 101, candesartan 81, ZD7155 11, and eprosartan 1.4. We conclude that, at least functionally, pre- and postjunctional angiotensin II AT(1) receptors are different and propose that the prejunctional. receptors in this tissue belong to the AT(1B)-subtype.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6