Smoking is an important risk factor for cardiovascular disease, in particular for acute cardiovascular events such as myocardial infarction and sudden death. The mechanisms linking smoking to acute cardiovascular events are not known. Sympathetic and hemodynamic responses to cigarette smoking may be implicated. Previous studies have demonstrated that smoking increases heart rate and blood pressure and decreases muscle sympathetic nerve activity (SNA) in healthy subjects. However, the baroreflex response to the increased blood pressure during smoking may be inhibiting muscle SNA and blunting the tachycardia during smoking. Thus, in patients with baroreflex impairment (patients with hypertension, coronary artery disease or heart failure), smoking may trigger increases in muscle SNA and potentiated increases in heart rate and blood pressure. It is not known whether these populations, who are most vulnerable to acute cardiovascular events, have a differential response to cigarette smoking in comparison to healthy control subjects. We propose a series of investigations that promise mechanistic insight into the effects of cigarette smoking and the link between smoking and acute cardiovascular events. We will test the following specific hypotheses. 1) In young healthy subjects, cigarette smoking increases baroreflex independent skin SNA. Attenuation of the pressor effect of cigarette smoking (using intravenous nitroprusside infusion) is accompanied by increases in muscle SNA. 2) In patients with baroreflex impairment (elderly subjects and patients with overt cardiovascular disease), there is an increase in muscle SNA and catecholamines and a potentiation of the pressor and heart rate responses to smoking. 3) The effects of cigarette smoking on skin SNA and muscle SNA are mediated by nicotine. The integrity of the proposed hypotheses are supported by exciting preliminary data. These studies build on our broad experience in investigating both smoking and neural circulatory control, and should contribute significantly to understanding the mechanisms linking cigarette smoking to acute cardiovascular events.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL061560-03
Application #
6224939
Study Section
Cardiovascular and Renal Study Section (CVB)
Project Start
1999-09-01
Project End
2004-01-31
Budget Start
2000-02-01
Budget End
2001-01-31
Support Year
3
Fiscal Year
2000
Total Cost
$265,195
Indirect Cost
Name
Mayo Clinic, Rochester
Department
Type
DUNS #
City
Rochester
State
MN
Country
United States
Zip Code
55905
Hering, Dagmara; Kucharska, Wieslawa; Kara, Tomas et al. (2011) Potentiated sympathetic and hemodynamic responses to alcohol in hypertensive vs. normotensive individuals. J Hypertens 29:537-41
Lanfranchi, Paola A; Ackerman, Michael J; Kara, Tomas et al. (2010) Gene-specific paradoxical QT responses during rapid eye movement sleep in women with congenital long QT syndrome. Heart Rhythm 7:1067-74
Swierblewska, Ewa; Hering, Dagmara; Kara, Tomas et al. (2010) An independent relationship between muscle sympathetic nerve activity and pulse wave velocity in normal humans. J Hypertens 28:979-84
Hering, Dagmara; Somers, Virend K; Kara, Tomas et al. (2008) Heightened acute circulatory responses to smoking in women. Blood Press 17:141-6
Kapa, Suraj; Sert Kuniyoshi, Fatima H; Somers, Virend K (2008) Sleep apnea and hypertension: interactions and implications for management. Hypertension 51:605-8
Okcay, Aynur; Somers, Virend K; Caples, Sean M (2008) Obstructive sleep apnea and hypertension. J Clin Hypertens (Greenwich) 10:549-55
Hausberg, Martin; Somers, Virend K (2008) Environmental smoke exposure: a complex cardiovascular challenge. Hypertension 51:1468-9
Ciecwierz, Dariusz; Hering, Dagmara; Somers, Virend K et al. (2007) Sympathetic neural responses to coronary occlusion during balloon angioplasty. J Hypertens 25:1650-4
Wolk, Robert; Snyder, Eric M; Somers, Virend K et al. (2007) Arginine 16 glycine beta2-adrenoceptor polymorphism and cardiovascular structure and function in patients with heart failure. J Am Soc Echocardiogr 20:290-7
Otto, Maria E; Belohlavek, Marek; Romero-Corral, Abel et al. (2007) Comparison of cardiac structural and functional changes in obese otherwise healthy adults with versus without obstructive sleep apnea. Am J Cardiol 99:1298-302

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