Responses of the rat cardiovascular system to substance P, neurotensin and bombesin
| Autor: | Loris A. Chahl, S. Belinda Walker |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Male
medicine.medical_specialty Mepyramine Blood Pressure Substance P Propranolol complex mixtures digestive system General Biochemistry Genetics and Molecular Biology chemistry.chemical_compound Phentolamine Heart Rate Internal medicine medicine Animals Anesthesia General Pharmacology Toxicology and Pharmaceutics Neurotensin musculoskeletal neural and ocular physiology Hemodynamics Bombesin Rats Inbred Strains General Medicine Rats Endocrinology chemistry Catecholamine Hexamethonium Peptides hormones hormone substitutes and hormone antagonists circulatory and respiratory physiology medicine.drug |
| Zdroj: | Life Sciences. 29:2009-2015 |
| ISSN: | 0024-3205 |
| DOI: | 10.1016/0024-3205(81)90611-1 |
| Popis: | The carotid arterial blood pressure and heart rate responses to intravenous injections of substance P, neurotensin and bombesin were compared in anaesthetized rats. In rats anaesthetized with urethane neurotensin produced only a fall in blood pressure but in rats anaesthetized with sodium thiobutabarbitone, the fall was preceded by a transient rise in blood pressure. The reason for the different responses to neurotensin with the two anaesthetics was not investigated. The hypotensive effect of neurotensin observed with both anaesthetics was abolished by mepyramine and therefore appeared to be mediated by action on H1 receptors either of neurotensin directly or of histamine released. On the other hand, catecholamines might be implicated in the pressor response to neurotensin observed in rats anaesthetized with sodium thiobutabarbitone since it was reduced by phentolamine and hexamethonium. Low doses of substance P produced a depressor response which was not inhibited by the antagonists tested. At higher doses marked tachycardia occurred and the depressor response was less and was often followed by a pressor response. The tachycardia was abolished by propranolol but not by cervical cord section or by hexamethonium. Bombesin produced a pressor response which was unaffected by hexamethonium but was reversed to depressor by phentolamine. This depressor response to bombesin was abolished by propranolol. It was concluded that substance P produced a depressor response by action on its own specific receptors and tachycardia by catecholamine release whereas neurotensin and bombesin produced cardiovascular actions which were mediated entirely by amine release. |
| Databáze: | OpenAIRE |
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