| Background:Sympathetic nervous system plays an important role in blood pressure regulation and response to position change. Some polymorphisms of genes encoding components of the sympathetic nervous system significantly increase the risk of hypertension, but it’s relation with orthostatic blood pressure was not widely studied. We then hypothesized that polymorphisms of genes encoding components of the sympathetic nervous system may impair the sympathetic function and then orthostatic blood pressure regulation in hypertensive patients.Methods:We recruited3630untreated hypertensive patients and826normotensive subjects aged40-75years from7rural communities. Orthostatic hypertension was defined as an increase in systolic blood pressure of20mmHg or more;orthostatic hypotension, as a drop in blood pressure of20/10mmHg or more, upon assumption of upright posture within3minutes. Polymorphisms of Gs protein alpha-subunit (GNAS1) gene T131/C,01-adrenergic receptor (AR) gene Arg389/Gly and β2-AR gene Arg16/Gly were determined.Results:No significant effect of genotypes/alleles was found on the prevalence of orthostatic hypertension. On the contrary, the prevalence of orthostatic hypotension was significantly different among GNAS1T131/C genotypes [17.5%vs.8.0%(CC vs. TT+TC), P<0.001] in male hypertensive patients, and β1AR Arg389/Gly genotypes [9.8%vs.4.0%(GG vs. CG+CC), P<0.001] in female hypertensive patients. After adjustment for conventional risk factors, both the GNAS1CC genotype (OR,3.59;95%CI,1.30to8.86) and β1adrenergic receptor Gly389homozygote (OR,3.10;95%CI,1.27to7.61) were independent risk factors for orthostatic hypotension. In normotensive controls, no association was identified between studied polymorphisms and OHT or OH after controlling for confounders.Conclusions:Our results indicate that polymorphisms of genes encoding components of the sympathetic nervous system was associated with orthostatic hypotension in hypertensive patients. |
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