title: Intracerebroventricular administration of angiotensin II increases heart rate in the conscious trout.
abstract: The central effect of angiotensin II on cardiovascular activity has been investigated in conscious trout bearing an intracerebroventricular (i.c.v.) cannula and an intra-arterial catheter. I.c.v. injection of the angiotensin II agonist [Asn1,Val5]AII (6.2-50 pmol) induced a dose-dependent increase in heart rate and arterial blood pressure. Central administration of the angiotensin II antagonist DuP 753 (5 nmol) 30 min before i.c.v. injection of [Asn1,Val5]AII totally prevented the tachycardia and reduced the hypertension induced by the angiotensin II agonist. Intra-arterial injection of arginine-vasotocin (12.5 pmol) caused a bradycardia associated with a marked increase in arterial blood pressure. I.c.v. injection of [Asn1,Val5]AII totally blocked the bradycardia induced by arginine-vasotocin and this effect was prevented by central administration of DuP 753. In contrast, [Asn1,Val5]AII did not affect the increase in blood pressure induced by arginine vasotocin. Suppression of the vagal tone by atropine treatment totally blocked the central effect of [Asn1,Val5]AII. These results show that angiotensin II acts directly on the trout brain to increase blood pressure and heart rate. The effect of angiotensin II is mediated through a receptor related to the mammalian AT1 receptor type.
authors.affiliation: Laboratoire de Neurophysiologie, UFR de Médecine, Université de Bretagne Occidentale, Brest, France.
authors.forename: J C
authors.initials: JC
authors.lastname: Le Mevel
authors.forename: T F
authors.initials: TF
authors.lastname: Pamantung
authors.forename: D
authors.initials: D
authors.lastname: Mabin
authors.forename: H
authors.initials: H
authors.lastname: Vaudry
mesh_terms: D000804:Angiotensin II / Q000819:agonists / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000008:administration & dosage / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D003243:Consciousness; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects*; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D007269:Injections, Intra-Arterial; D007276:Injections, Intraventricular; D019808:Losartan; D013777:Tetrazoles / Q000008:administration & dosage / Q000494:pharmacology*; D014337:Trout
chemical_list: D001713:Biphenyl Compounds; D007093:Imidazoles; D013777:Tetrazoles; D000804:Angiotensin II; C031193:angiotensin II, Asp(1)-Val(5)-; D001285:Atropine; D019808:Losartan