Regulation of protein synthesis by alpha 1-adrenergic receptor subtypes in cultured rabbit aortic vascular smooth muscle cells

J Cardiovasc Pharmacol. 1996 Apr;27(4):508-18. doi: 10.1097/00005344-199604000-00009.


To investigate the role of the sympathetic nervous system in maintenance and remodeling of vascular smooth muscle, we have examined regulation of protein synthesis by alpha 1-adrenergic receptors (alpha 1-AR) in cultured rabbit aortic vascular smooth muscle cells (VSMC). Stimulation of postconfluent cultures (passages 2-6) in serum-free growth medium with the alpha-AR agonist phenylephrine (PE, 30 microM) increases protein synthesis, measured as [3H]leucine incorporation into protein (146 +/- 5%, p < or = 0.001) and total protein content (117 +/- 2%, p < or = 0.001). PE treatment does not affect cellular proliferation or [3H]thymidine incorporation into DNA. PE-stimulated protein synthesis is evident within 24 h, sustained over 96 h, concentration-dependent, and saturable. PE-elicited responses are completely inhibited by the alpha 1-AR antagonist prazosin but not by the alpha 2-AR antagonist yohimbine or the beta-AR antagonists propranolol and atenolol; the beta-AR agonist isoproterenol is ineffective. Competition with [3H]prazosin occupancy of alpha 1-AR and agonist-elicited [3H]leucine incorporation by subtype-selective receptor antagonists (WB4101 and 5-methylurapidil, alpha 1A; chloroethylclonidine, alpha 1B) demonstrates that these cells express a majority of alpha 1B-AR (75%) relative to alpha 1A-AR (25%), which elicit protein metabolism in proportion to their relative abundances. These results indicate that alpha 1B-AR predominate in coupling to metabolic responses, in contrast to previous reports that contractile responses in this tissue are preferentially mediated by alpha 1A-AR.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic alpha-1 Receptor Agonists*
  • Adrenergic alpha-Agonists / pharmacology*
  • Adrenergic beta-Agonists / pharmacology
  • Animals
  • Aorta, Thoracic / metabolism
  • Cell Division / drug effects
  • Cells, Cultured
  • In Vitro Techniques
  • Male
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / metabolism*
  • Phenylephrine / pharmacology*
  • Protein Biosynthesis*
  • Rabbits
  • Time Factors


  • Adrenergic alpha-1 Receptor Agonists
  • Adrenergic alpha-Agonists
  • Adrenergic beta-Agonists
  • Phenylephrine