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Cigarette smoking and the adrenergic nervous system
G Grassi1, G Seravalle, D A Calhoun
1Cattedra di Semeiotica Medica, Università di Milano, Italy.
Summary
Cigarette smoking acutely raises blood pressure and heart rate. Contrary to belief, smoking reduces central sympathetic nerve activity, indicating peripheral mechanisms drive these cardiovascular changes.
Area of Science:
- Cardiovascular Physiology
- Neuroendocrinology
- Autonomic Nervous System
Background:
- Cigarette smoking acutely increases blood pressure and heart rate.
- This response is traditionally attributed to stimulation of the adrenergic nervous system.
Purpose of the Study:
- To investigate whether the adrenergic stimulation during smoking is central or peripheral.
- To elucidate the mechanisms behind the acute hemodynamic effects of smoking.
Main Methods:
- Direct recording of efferent post-ganglionic sympathetic nerve activity using microneurography from the peroneal nerve.
- Measurement of blood pressure, heart rate, and plasma catecholamines (norepinephrine and epinephrine).
Main Results:
- Smoking significantly increased blood pressure, heart rate, and plasma norepinephrine and epinephrine.
- Concurrently, sympathetic nerve activity showed a marked reduction.
Conclusions:
- Peripheral mechanisms, not central sympathetic activation, explain the adrenergic involvement in smoking's acute hemodynamic effects.
- Central sympathetic drive is inhibited during smoking, likely due to arterial baroreceptor stimulation.