Leakage of catecholamines from rabbit cerebrospinal fluid following intracerebroventricular injection.

Abstract

The intracerebroventricular (i.c.v.) injection of (-)-isoprenaline and the selective beta 1-adrenoceptor agonist, RO363, elicited reproducible dose-related increases in heart rate in unanaesthetized and anaesthetized rabbits. (-)-Isoprenaline produced vasodepressor effects in unanaesthetized animals, whereas both catecholamines decreased blood pressure in anaesthetized rabbits. Pretreatment with guanethidine sulphate (5 mg/kg i.v.) reduced but did not abolish the tachycardia elicited by i.c.v. RO363, whereas heart rate responses to i.c.v. (-)-isoprenaline were unaffected. Pretreatment of anaesthetized rabbits with hexamethonium bromide (10 mg/kg i.v.) did not markedly affect the tachycardia elicited by i.c.v. RO363 and reduced the response to i.c.v. (-)-isoprenaline in only one out of five experiments. The results suggest that there is a marked leakage of centrally administered catecholamines into the peripheral circulation and that the rabbit may be unsuited for examining centrally mediated cardiovascular effects of catecholamines.

• Authors: C Maccarrone, E Malta, C Raper
• Journal: Clinical and experimental pharmacology & physiology (Clin Exp Pharmacol Physiol) 1983 Jul-Aug Vol. 10 Issue 4 Pg. 421-5 ISSN: 0305-1870 [Print] Australia
• PMID: 6138175 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Adrenergic beta-Agonists
• Catecholamines
• Catechols
• Hexamethonium Compounds
• Propanolamines
• Hexamethonium
• Ro 363
• Isoproterenol
• Guanethidine

Topics

• Adrenergic beta-Agonists (pharmacology)
• Animals
• Catecholamines (cerebrospinal fluid)
• Catechols
• Guanethidine (pharmacology)
• Hexamethonium
• Hexamethonium Compounds (pharmacology)
• Injections, Intraventricular
• Isoproterenol (administration & dosage, pharmacology)
• Propanolamines (administration & dosage, pharmacology)
• Rabbits