Central and peripheral cardiovascular effects of angiotensin III in trout.
The present study was undertaken to determine the central and peripheral actions of trout angiotensin III (ANG III) on heart rate (HR) and mean dorsal aortic blood pressure (P(DA)) in the unanaesthetized rainbow trout. Intracerebroventricular injection of ANG III (5-100 pmol) produced a significant and dose-dependent increase in HR without significant change in P(DA). In contrast, when injected peripherally ANG III (5-50 pmol) evoked a significant and dose-dependent increase in P(DA). The hypertensive responses were accompanied by a bradycardia that reached significance only for the highest dose of ANG III tested. In conclusion, our results have shown that ANG III has potent and contrasting cardiovascular actions depending on whether its site of action is the brain or the peripheral circulation. Endogenous ANG III may have important physiological functions in teleost fishes.
Mimassi
N
N
Université Européenne de Bretagne, Université de Brest, Institut National de la Santé et de la Recherche Médicale (U650), IFR 148 ScInBioS, Centre Hospitalier Universitaire de Brest, Brest, France.
Lancien
F
F
Le Mével
J C
JC
D000805:Angiotensin III / Q000494:pharmacology*; D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects*; D014337:Trout
D000805:Angiotensin III