Key result
Photolysis of rabbit aortic strips with three consecutive doses of 0.1 microM nitroazidobenzoyl-angiotensin II resulted in a 62% loss of response to subsequent doses.
Photochemical inactivation of the angiotensin receptor in rabbit aorta demonstrates specific, long-lasting receptor inhibition mediated via the angiotensin II binding site.
Shows irreversible angiotensin receptor inactivation ex vivo; leaves open translation to in vivo or clinical angiotensin modulation.
The photoaffinity label N alpha-(2-nitro-5-azidobenzoyl)-[Asp1,Ile5]angiotensin II (nitroazidobenzoyl-angiotensin II) has a pD2 of 7.22 in the rabbit aortic strip assay compared to 8.44 for [Asp1,Ile5]angiotensin II and can be completely inhibited by [Sar1, Ala8]angiotensin II. Photolysis of a single dose of nitroazidobenzoyl-angiotensin II (0.1 microM) with aortic strips for 3 min with light of wavelengths of greater than 320 nm, followed by washing, resulted in loss of approximately 25% of the strip's response to a subsequent dose of nitroazidobenzoyl-angiotensin II. Photolysis of three consecutive doses of label resulted in loss of 62% of the strips response to a subsequent dose. Repetitive exposure to label in the dark and repetitive photolyses without label resulted in loss of no more than 20% of the strips ability to respond to angiotensin II. Photolysis with three consecutive doses of 0.1 microM nitroazidobenzoyl-angiotensin II in the presence of 0.5 microM of the competitive inhibitor [Sar1,Ala8]angiotensin II decreased the observed inhibition from 62 to 22%. The long-lasting inhibition observed after photolysis with 0.1 microM nitroazidobenzoyl-angiotensin II therefore occurred via photolysis of some part of the nitroazidobenzoyl chromophore. This inhibition was mediated via the receptor that binds [Sar1,Ala8]angiotensin II and, therefore, angiotensin II.
No takes yet. Share an insight, caveat, or question.
Galardy et al. (1981) studied this question. nitroazidobenzoyl-angiotensin II vs. exposure in the dark or photolyses without label was evaluated on loss of strip's response to a subsequent dose. Photolysis of rabbit aortic strips with three consecutive doses of 0.1 microM nitroazidobenzoyl-angiotensin II resulted in a 62% loss of response to subsequent doses.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: