Expression of α2-adrenergic receptors (α2-AR) is very high in fetal rat heart although numbers decline with increasing gestational age. The current experiments were designed to identify the subtypes of α2-AR expressed and the function of these receptors in fetal cardiac myocytes. Expression of α2A and α2C, but not α2B, was confirmed in the myocyte population by indirect immunofluorescence microscopy with subtype-specific antibodies and by Western blot. Both dexmedetomidine, an α2-selective agonist, and norepinephrine, increased actin cytoskeleton organization and this increase was blocked by the α2-selective antagonist, atipamezole. Furthermore, dexmedetomidine inhibited isoproterenol-stimulated cAMP accumulation in isolated fetal rat heart and this was blocked by rauwolscine. Therefore, functional α2A and α2B subtypes are present in the fetal rat heart where they may have a role in cardiac development.
- Fetal heart
- α-adrenergic receptors
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)