Abstract
It is unknown whether amiodarone exerts a direct central action on the cardiovascular autonomic nervous system. This study was designed to evaluate the effects of acute amiodarone administration on vagal and sympathetic efferent nerve discharges. Experiments were carried out in 25 decerebrate unanesthetized rats. In one group, vagal activity was recorded from preganglionic fibers isolated from the cervical vagus nerve. In another group, sympathetic recordings were obtained from fibers isolated from the cervical sympathetic trunk in intact conditions or after barodenervation. Recordings were performed before and for 60 min after amiodarone (50 mg/kg iv) administration. In all groups, amiodarone induced bradycardia and hypotension. Vagal activity increased immediately, reaching a significant difference after 20 min (260 ± 131% from 16.4 ± 3.3 spikes/s) and was unmodified by the barodenervation. At difference, sympathetic activity after an initial and short-lasting increase (150 ± 83% from 24.8 ± 5.7 spikes/s) began to decrease significantly after 20 min (36 ± 17%) throughout the experiment. The initial increase in sympathetic activity was not observed in barodenervated animals. These changes in vagal and sympathetic activity could play an important role in contributing to the antiarrhythmic action of amiodarone.
| Original language | English |
|---|---|
| Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
| Volume | 283 |
| Issue number | 2 52-2 |
| Publication status | Published - 2002 |
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Keywords
- Arrhythmias
- Autonomic nervous system
- Baroreceptors
- Heart rate
ASJC Scopus subject areas
- Physiology
Cite this
Opposite effects of iv amiodarone on cardiovascular vagal and sympathetic efferent activities in rats. / Silva, Valdo Jose Dias Da; Gnecchi-Ruscone, Tomaso; Lavelli, Barbara; Bellina, Valentina; Manzella, Daniela; Porta, Alberto; Malliani, Alberto; Montano, Nicola.
In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 283, No. 2 52-2, 2002.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Opposite effects of iv amiodarone on cardiovascular vagal and sympathetic efferent activities in rats
AU - Silva, Valdo Jose Dias Da
AU - Gnecchi-Ruscone, Tomaso
AU - Lavelli, Barbara
AU - Bellina, Valentina
AU - Manzella, Daniela
AU - Porta, Alberto
AU - Malliani, Alberto
AU - Montano, Nicola
PY - 2002
Y1 - 2002
N2 - It is unknown whether amiodarone exerts a direct central action on the cardiovascular autonomic nervous system. This study was designed to evaluate the effects of acute amiodarone administration on vagal and sympathetic efferent nerve discharges. Experiments were carried out in 25 decerebrate unanesthetized rats. In one group, vagal activity was recorded from preganglionic fibers isolated from the cervical vagus nerve. In another group, sympathetic recordings were obtained from fibers isolated from the cervical sympathetic trunk in intact conditions or after barodenervation. Recordings were performed before and for 60 min after amiodarone (50 mg/kg iv) administration. In all groups, amiodarone induced bradycardia and hypotension. Vagal activity increased immediately, reaching a significant difference after 20 min (260 ± 131% from 16.4 ± 3.3 spikes/s) and was unmodified by the barodenervation. At difference, sympathetic activity after an initial and short-lasting increase (150 ± 83% from 24.8 ± 5.7 spikes/s) began to decrease significantly after 20 min (36 ± 17%) throughout the experiment. The initial increase in sympathetic activity was not observed in barodenervated animals. These changes in vagal and sympathetic activity could play an important role in contributing to the antiarrhythmic action of amiodarone.
AB - It is unknown whether amiodarone exerts a direct central action on the cardiovascular autonomic nervous system. This study was designed to evaluate the effects of acute amiodarone administration on vagal and sympathetic efferent nerve discharges. Experiments were carried out in 25 decerebrate unanesthetized rats. In one group, vagal activity was recorded from preganglionic fibers isolated from the cervical vagus nerve. In another group, sympathetic recordings were obtained from fibers isolated from the cervical sympathetic trunk in intact conditions or after barodenervation. Recordings were performed before and for 60 min after amiodarone (50 mg/kg iv) administration. In all groups, amiodarone induced bradycardia and hypotension. Vagal activity increased immediately, reaching a significant difference after 20 min (260 ± 131% from 16.4 ± 3.3 spikes/s) and was unmodified by the barodenervation. At difference, sympathetic activity after an initial and short-lasting increase (150 ± 83% from 24.8 ± 5.7 spikes/s) began to decrease significantly after 20 min (36 ± 17%) throughout the experiment. The initial increase in sympathetic activity was not observed in barodenervated animals. These changes in vagal and sympathetic activity could play an important role in contributing to the antiarrhythmic action of amiodarone.
KW - Arrhythmias
KW - Autonomic nervous system
KW - Baroreceptors
KW - Heart rate
UR - http://www.scopus.com/inward/record.url?scp=0036333544&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036333544&partnerID=8YFLogxK
M3 - Article
C2 - 12121869
AN - SCOPUS:0036333544
VL - 283
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6119
IS - 2 52-2
ER -