In normotensive postmenopausal women, chronic transdermal ERT decreases SND without augmenting arterial baroreflexes and causes a small but statistically significant decrease in ambulatory BP. Sympathetic inhibition is evident only with chronic rather than acute estrogen administration, implying a genomic mechanism of action. Because the effects of transdermal ERT are larger than those of oral ERT, the route of administration may be an important consideration in optimizing the beneficial effects of ERT on BP and overall cardiovascular health.

These studies provide direct microneurographic evidence in humans that intranasal cocaine stimulates central sympathetic outflow. This central sympathetic activation appears to be targeted not only to the cutaneous circulation promoting peripheral vasoconstriction but also to the heart promoting tachycardia.

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Abstract-A large body of clinical investigation implicates an important role for the sympathetic nervous system in linking obesity with hypertension. However, the experimental support for this hypothesis is derived from strictly white cohorts. The goal of this study was to determine whether being overweight begets sympathetic overactivity in black Americans, the ethnic minority at highest risk for hypertension. We recorded postganglionic sympathetic nerve discharge with microelectrodes in muscle nerve fascicles of the peroneal nerve in 92 normotensive young adult black men and women within a wide range of body mass index. The same experiments were performed in a control group of 45 normotensive white men and women of similar ages and body mass indices. The major new findings are 2-fold. First, in young, normotensive, overtly healthy black women, being overweight begets sympathetic overactivity (rϭ0.45, Pϭ0.0009), a putative intermediate phenotype for incident hypertension. Second, in black men, sympathetic nerve discharge is dissociated from body mass index (rϭ0.03, PϭNS). This dissociation is explained in part by a 20% to 40% higher rate of sympathetic nerve discharge in lean black men compared with lean white men and lean black and white women (28Ϯ3 versus 18Ϯ2, 21Ϯ2, and 17Ϯ2 bursts/min, respectively; PϽ0.05). Sympathetic nerve discharge in lean black men is comparable to that of overweight black men and women as well as white men and women. These data provide the first microneurographic evidence for tonic central sympathetic overactivity in blacks, both adiposity-related sympathetic overactivity in black women and adiposity-independent sympathetic overactivity in black men. Key Words: obesity Ⅲ sympathetic nervous system Ⅲ blacks Ⅲ blood pressure O besity is firmly established to be a major risk factor for hypertension, and a large body of clinical investigation implicates an important role for the sympathetic nervous system in linking adiposity with hypertension. [1][2][3][4][5][6] In numerous studies of normotensive young adults, increasing adiposity is accompanied by increased sympathetic nerve discharge (SND) to skeletal muscle, a major site of energy expenditure. 5-7 Overweight-related sympathetic overactivity is hypothesized to be a compensatory mechanism to burn fat and minimize weight gain but at the cost of increased sympathetic discharge to the peripheral vasculature, which could predispose to hypertension. 2,8 However, the experimental support for this hypothesis is derived from strictly white cohorts. 5,6 The importance of inclusion of minority subjects in this field of clinical investigation is underscored by recent studies of Pima Indians, an ethnic minority with a high prevalence of obesity but a comparatively low prevalence of hypertension. 4 Basal levels of skeletal muscle SND are lower in normotensive male Pima Indians than in whites and do not track with adiposity. This relative sympathetic underactivity constitutes a potential explanation for the surprisingly low prevalence of hypertensio...

Drug delivery and lung deposition from a dry powder inhaler (DPI) are dependent on the peak inspiratory flow (PIF) through the DPI. Therefore, when prescribing a DPI, it is important to know whether a child is able to generate sufficient PIF through a particular device. Using a PIF meter (In-Check Dial) that mimics the internal resistance of DPIs, two commonly used devices (high-resistance Turbohaler (TH) and low-resistance Diskus (DK)) determined the PIF generated by asthmatic children through each of them. Two hundred and twenty-three children were studied, of whom 100 (mean age, 9.1 +/- 3.0 years; range, 3-15 years) were experienced with the use of a DPI (>1 month of regular DPI use), and 123 (mean, 5.5 +/- 1.9 years; range, 3-9 years) were inexperienced (no previous DPI use). All of the experienced patients generated more than 30 l/min through both devices, but a PIF of 60 l/min through the TH was obtained by only 68 (68%) of them. The age above which a minimal PIF of 30 l/min (for DK) or 60 l/min (for TH) could be achieved in new DPI users (inexperienced) was 4 years and 9 years, respectively. Even among experienced patients, many young children may not generate optimal PIFs through high-resistance DPIs. When DPI treatment is considered for young children, some devices may be successfully introduced at a younger age. It may thus be important to measure PIF in children who use a DPI or in whom DPI use is contemplated. This evaluation can be easily undertaken in the clinic with the In-Check Dial device.