title: Race and sex differences in cardiovascular α-adrenergic and β-adrenergic receptor responsiveness in men and women with high blood pressure.
abstract: Hypertension is associated with unfavorable changes in adrenergic receptor responsiveness, but the relationship of race and sex to adrenergic receptor responsiveness in the development of cardiovascular disease is unclear. This study examined α-adrenergic and ß-adrenergic receptor responsiveness in African-American and white men and women with untreated high blood pressure (BP) (HBP) and with normal BP.
  
  
  
  The study sample comprised 161 African-American and white men and women in the age range 25-45 years. Isoproterenol, a nonselective ß-adrenergic receptor agonist, was administered intravenously to determine the bolus dose required to increase heart rate by 25 bpm, an index of β-adrenergic receptor responsiveness. Similarly, phenylephrine, an α1-adrenergic receptor agonist, was administered to determine the bolus dose required to increase BP by 25 mmHg, an index of vascular α1-adrenergic receptor responsiveness. HBP (P < 0.01), male sex (P = 0.04), and higher BMI (P < 0.01) were all associated with reduced β-adrenergic receptor responsiveness, with a similar trend observed for African-American race (P = 0.07). Conversely, α1-adrenergic receptor responsiveness was increased in association with HBP (P < 0.01), female sex (P < 0.01), and African-American race (P < 0.01).
  
  
  
  In the early stages of hypertension, cardiovascular β-adrenergic receptors demonstrate blunted responsiveness, whereas conversely α1-adrenergic receptors exhibit increased responsiveness. This pattern of receptor changes is especially evident in men and African-Americans, is exacerbated by obesity, and may contribute to the development of cardiovascular disease.
authors.affiliation: aDepartment of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham bDepartment of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Sherwood
authors.forename: LaBarron K
authors.initials: LK
authors.lastname: Hill
authors.forename: James A
authors.initials: JA
authors.lastname: Blumenthal
authors.forename: Kristy S
authors.initials: KS
authors.lastname: Johnson
authors.forename: Alan L
authors.initials: AL
authors.lastname: Hinderliter
mesh_terms: D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology; D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000328:Adult; D001741:Black or African American; D001794:Blood Pressure / Q000187:drug effects*; D015992:Body Mass Index; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D012737:Sex Factors; D044465:White People
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000318:Adrenergic beta-Agonists; D018340:Receptors, Adrenergic, alpha-1; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; D007545:Isoproterenol; D009638:Norepinephrine