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Adrian Gericke, Marcin L. Kordasz, Andreas Steege, Atsushi Sanbe, Evgeny Goloborodko, Jan M. Vetter, Andreas Patzak, Norbert Pfeiffer; Functional Role of α1-Adrenoceptor Subtypes in Murine Ophthalmic Arteries. Invest. Ophthalmol. Vis. Sci. 2011;52(7):4795-4799. doi: 10.1167/iovs.11-7516.
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© ARVO (1962-2015); The Authors (2016-present)
To identify the α1-adrenoceptor (α1-AR) subtypes mediating vascular adrenergic responses in murine ophthalmic arteries.
Expression of mRNA was quantified for individual α1-AR subtypes in murine ophthalmic arteries using real-time PCR. To assess the functional relevance of α1-ARs for mediating vascular responses, ophthalmic arteries from mice deficient in one of the three α1-AR subtypes (α1A-AR−/−, α1B-AR−/−, and α1D-AR−/−, respectively) and wild-type controls were isolated, cannulated with micropipettes, and pressurized. Changes in luminal artery diameter in response to the α1-AR agonist phenylephrine, the sympathetic transmitter noradrenaline, and to the nonadrenergic vasoconstrictor arginine vasopressin (AVP) were measured by video microscopy.
Using real-time PCR, mRNA for all three α1-AR subtypes was detected in ophthalmic arteries from wild-type mice. In functional studies, phenylephrine and noradrenaline produced dose-dependent constriction of ophthalmic arteries that was similar in wild-type, α1B-AR−/−, and α1D-AR−/− mice. Strikingly, responses to phenylephrine and noradrenaline were almost completely abolished in α1A-AR−/− mice. In contrast, the nonadrenergic agonist AVP produced dose-dependent vasoconstrictor responses that did not differ between any of the mouse genotypes tested.
These findings provide evidence that the α1A-AR subtype mediates adrenergic vasoconstriction in murine ophthalmic arteries.
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