Does cardiac-specific expression of a constitutively active alpha 1B-adrenergic receptor induce cardiac hypertrophy in transgenic mice?
Cardiac-specific expression of a constitutively active alpha 1B-adrenergic receptor in transgenic mice induces cardiac hypertrophy, providing a useful experimental model for studying the biochemical triggers of this condition.
Transgenic mice were generated by using the alpha-myosin heavy chain promoter coupled to the coding sequence of a constitutively active mutant alpha 1B-adrenergic receptor (AR). These transgenic animals demonstrated cardiac-specific expression of this alpha 1-AR with resultant activation of phospholipase C as shown by increased myocardial diacylglycerol content. A phenotype consistent with cardiac hypertrophy developed in adult transgenic mice with increased heart/body weight ratios, myocyte cross-sectional areas, and ventricular atrial natriuretic factor mRNA levels relative to nontransgenic controls. These transgenic animals may provide insight into the biochemical triggers that induce hypertrophy in cardiac disease and serve as a convenient experimental model for studies of this condition.
Milano et al. (Tue,) studied this question.