Cardiac α1A-AR mRNA and receptor levels are normal in the knockin mouse (GqKI) with a 6-amino acid substitution in the 3rd intracellular loop of the α1A. A. Diagram of the mutation: CCPGCC replaces DSEQVT at amino acid 228. B. α1-AR subtype mRNA levels in AMVMs (AU/HKGs, arbitrary units relative to 2 house keeping genes). C. Saturation binding for total α1-ARs in WT and mutant heart. WT levels are identical to those reported previously (Rokosh et al., 2002; Myagmar et al., 2017).18,34
D. Competition binding to identify the α1A as the site with high 5-methylurapidil affinity, ~20% α1A in both WT and GqKI. Prism was used for nonlinear fitting in C and D. All Ns are hearts.