Abstract |
The effect of serotonin on cardiac sympathetic transmission was investigated in vagotomized and cardiac decentralized dogs. Administration of serotonin in doses of 10-100 micrograms/kg i.v., during the resting unstimulated state caused tachycardia and pressor responses which were inhibited by cyproheptadine but not by guanethidine. The tachycardia was reduced by a beta-adrenoceptor antagonist, bufetolol. Serotonin in doses of 3-100 micrograms/kg depressed the elevated heart rate during maintained electrical stimulation of the cardiac sympathetic nerves. Cyproheptadine did not antagonize the serotonin-induced depression of the stimulation-elevated heart rate, while desipramine attenuated but did not abolish it. Serotonin did not have a significant effect on the heart rate elevated by maintained infusion of noradrenaline. The present results suggest that serotonin-induced depression of heart rate during sympathetic nerve stimulation is due to presynaptic inhibition by serotonin of cardiac sympathetic transmission which is not mediated via 'classic' tryptaminergic receptors.
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Authors | T Kimura, S Satoh |
Journal | Clinical and experimental pharmacology & physiology
(Clin Exp Pharmacol Physiol)
1983 Sep-Oct
Vol. 10
Issue 5
Pg. 535-42
ISSN: 0305-1870 [Print] Australia |
PMID | 6315283
(Publication Type: Journal Article)
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Chemical References |
- Cyproheptadine
- Serotonin
- Atropine
- Norepinephrine
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Topics |
- Animals
- Atropine
(pharmacology)
- Cyproheptadine
(pharmacology)
- Dogs
- Electric Stimulation
- Heart
(innervation)
- Heart Rate
(drug effects)
- Male
- Norepinephrine
(pharmacology)
- Serotonin
(pharmacology)
- Sympathetic Nervous System
(drug effects)
- Synaptic Transmission
(drug effects)
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