Variability in vascular responsiveness between Mexican–Americans and White Americans

Dachman, W; Adubofour, KO; Kapoor, Charanjit; Rackleff, D

doi:10.1038/sj.jhh.1000577

Cited by 5 publications

(2 citation statements)

References 15 publications

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“…20 In a study among 24 white and black Americans, Eichler et al found a lower E max in African Americans compared to Caucasians and a lower ED 50 (245 and 342 ng/min for African Americans and Caucasians, respectively), although the latter was not statistically significant (P=0.50). 21 In contrast, in this present study, using a much larger cohort we found a similar, but statistically significant racial difference in ED 50 , and additionally a trend to increased E max in African Americans compared to Caucasians.…”

Section: Discussionmentioning

confidence: 92%

Blacks Have a Greater Sensitivity to α ₁ -Adrenoceptor–Mediated Venoconstriction Compared With Whites

et al. 2013

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African Americans have increased hemodynamic responses to both physiologic and pharmacologic adrenergic stimulation compared to Caucasians, and this may contribute to the greater prevalence of hypertension in this ethnic group. A small study suggested enhanced α1-adrenoreceptor-mediated arterial vasoconstriction in the forearm vasculature of African Americans compared to Caucasians, but it is unknown whether this reflects a generalized vascular phenomenon. The objective of this study was to examine the hypothesis that there are ethnic differences in venous α1-adrenoreceptor responsiveness. Using a linear variable differential transformer, we measured local dorsal hand vein responses to increasing doses of the selective α1-adrenoreceptor agonist, phenylephrine, in 106 subjects (64 Caucasians and 42 African Americans). There was wide interindividual variability in responses to phenylephrine. The dose that produced 50% of maximal constriction (ED50) ranged from 11 to 5442 ng/min, and maximal venoconstriction (Emax) ranged from 13.5% to 100%. African Americans (geometric mean ED50=172 ng/min; 95% CI, 115 to 256 ng/min) were more sensitive to phenylephrine than Caucasians (310 ng/min; 95% CI, 222 to 434 ng/min; unadjusted P=0.026; adjusted P=0.003). Median Emax was slightly higher in African Americans (89%; IQR, 82% to 98%) compared to Caucasians (85%; IQR, 75% to 95%; P=0.07). Taken together with previous findings in arterial vessels, our results suggest a generalized increased sensitivity to α1-adrenoreceptor-mediated vasoconstriction in African Americans. Increased vascular α-adrenoreceptor sensitivity could predispose to hypertension, and future studies addressing this mechanism’s contribution to ethnic differences in the prevalence of hypertension will be of interest.

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Section: Discussionmentioning

confidence: 92%

Blacks Have a Greater Sensitivity to α ₁ -Adrenoceptor–Mediated Venoconstriction Compared With Whites

et al. 2013

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“…Luthra et al 16 reported very similar ED 50 values of norepinephrine in pairs of monozygotic twins that differed considerably in dizygotic twins. Eichler et al 17 and Dachmann et al 18 provided evidence that venous responses to α‐adrenoceptor agonists may be genetically determined.…”

Section: Discussionmentioning

confidence: 99%

Reproducibility of Dorsal Hand Vein Responses to Phenylephrine and Prostaglandin F_2α Using the Dorsal Hand Vein Compliance Method

Schindler

Großmann

Dobrev

et al. 2003

The Journal of Clinical Pharma

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Assessment of drug-induced venodilation by the dorsal hand vein compliance method requires stable constriction of the vein. This study was designed to investigate intra- and intersubject reproducibility of the venous preconstriction technique in response to phenylephrine and prostaglandin F2 alpha and to determine the influence of basal vein size. Twelve healthy male nonsmokers participated in a prospective cross-over study. Inter- and intrasubject variability was tested in response to phenylephrine and PGF2 alpha on different study days in the same hand vein. The dose of the respective constrictor causing approximately 80% constriction of the vein (ED80) was determined and infused for another 100 minutes. Actual vein size was measured every 5 minutes. Coefficient of variation and regression analyses were performed to analyze influence of vessel size on ED80 of the respective constrictor. Adjusted constriction levels were stable and well reproducible in all subjects. The intersubject coefficient of variation of ED80 ranged from 0.9% to 6.7% for phenylephrine and from 0.9% to 6.9% for PGF2 alpha. Whereas responses to phenylephrine were independent of basal vein diameter, there was a positive correlation between ED80 of PGF2 alpha and basal vein size. Thus, the hand vein compliance method is a suitable method to study dilatory responses in phenylephrine- or PGF2 alpha-constricted veins with considerable interindividual but small intraindividual variability. However, in such studies, phenylephrine appears to be a more reliable tool than PGF2 alpha.

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Acculturation to Western Society as a Risk Factor for High Blood Pressure: A Meta-Analytic Review

Steffen

Smith

Larson

et al. 2006

Psychosomatic Medicine

165

140

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Variability in vascular responsiveness between Mexican–Americans and White Americans

Cited by 5 publications

References 15 publications

Blacks Have a Greater Sensitivity to α ₁ -Adrenoceptor–Mediated Venoconstriction Compared With Whites

Blacks Have a Greater Sensitivity to α ₁ -Adrenoceptor–Mediated Venoconstriction Compared With Whites

Reproducibility of Dorsal Hand Vein Responses to Phenylephrine and Prostaglandin F_2α Using the Dorsal Hand Vein Compliance Method

Acculturation to Western Society as a Risk Factor for High Blood Pressure: A Meta-Analytic Review

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Variability in vascular responsiveness between Mexican–Americans and White Americans

Cited by 5 publications

References 15 publications

Blacks Have a Greater Sensitivity to α 1 -Adrenoceptor–Mediated Venoconstriction Compared With Whites

Blacks Have a Greater Sensitivity to α 1 -Adrenoceptor–Mediated Venoconstriction Compared With Whites

Reproducibility of Dorsal Hand Vein Responses to Phenylephrine and Prostaglandin F2α Using the Dorsal Hand Vein Compliance Method

Acculturation to Western Society as a Risk Factor for High Blood Pressure: A Meta-Analytic Review

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Product

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Blacks Have a Greater Sensitivity to α ₁ -Adrenoceptor–Mediated Venoconstriction Compared With Whites

Blacks Have a Greater Sensitivity to α ₁ -Adrenoceptor–Mediated Venoconstriction Compared With Whites

Reproducibility of Dorsal Hand Vein Responses to Phenylephrine and Prostaglandin F_2α Using the Dorsal Hand Vein Compliance Method