Negative Chronotropic Effect of Catecholamines on Adrenergic Receptors in Cardiac Ganglia in the Spinal Dog
| Autor: | Kazushi Kushiku, Tatsuo Furukawa, Hiro-o Kamiya, Seiichi Ichimasa |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
Male
Chronotropic medicine.medical_specialty Adrenergic receptor Dopamine Adrenergic beta-Antagonists Propranolol Catecholamines Dogs Phentolamine Heart Rate Internal medicine medicine Animals Chlorpromazine Adrenergic alpha-Antagonists Pharmacology Ganglia Sympathetic business.industry Heart Receptors Adrenergic Apomorphine Epinephrine Endocrinology Spinal Cord Depression Chemical Female Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | Journal of Cardiovascular Pharmacology. 2:857-866 |
| ISSN: | 0160-2446 |
| DOI: | 10.1097/00005344-198011000-00014 |
| Popis: | The effects of catecholamines (CAs) on cardiac chronotropism were investigated in the spinal dog. The CAs were administered through the right subclavian artery (i.a.) to reach the cardiac sympathetic ganglia. Without preganglionic stimulation. CAs administered intra-arterially induced a slight negative chronotropic effect, which was reversed to a positive chronotropic effect after neostigmine (200 microgram, i.a.) in many cases. With preganglionic stimulation, intra-arterial injection of norepinephrine (0.5-25 microgram), epinephrine (0.1-10 microgram), or dopamine (0.1-500 microgram) caused dose-dependent bradycardia. The negative chronotropic effect of dopamine was significantly inhibited intra-arterial phentolamine (2 mg), dihydroergotamine (0.4 mg), apomorphine (0.5 mg), haloperidol (0.5 mg), or chlorpromazine (5 mg) but not by propranolol (0.1 mg) or bulbocapnine (1 mg), whereas the same effect of epinephrine was significantly reduced by alpha-blockade but not by propranolol or the dopamine antagonists. These results suggest that CAs exert a negative chronotropic action by inhibiting cardiac ganglionic transmission and that the receptors for dopamine are alpha-adrenergic and dopamine-specific and those for epinephrine are alpha-adrenergic specific. |
| Databáze: | OpenAIRE |
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