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The vasopressor action of angiotensin II (ANG II) in ball pythons (Python regius).

Authors
  • Hansen, Line Mathilde Brostrup1
  • Wang, Tobias2
  • 1 Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark. Electronic address: [email protected] , (Denmark)
  • 2 Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark; Aarhus Institute of Advanced Studies, 8000 Aarhus C, Denmark. , (Denmark)
Type
Published Article
Journal
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology
Publication Date
Feb 01, 2021
Volume
252
Pages
110839–110839
Identifiers
DOI: 10.1016/j.cbpa.2020.110839
PMID: 33166686
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Angiotensin II (ANG II) is part of the renin-angiotensin system (RAS) in vertebrates and exert vasoconstriction in all species studied. The present study examines the vasopressor effect of ANG II in the ball python (Python regius), and examines whether ANG II exert its effect through direct angiotensin receptors or through an activation of α-adrenergic receptors. The studies were conducted in snakes with chronic arterial catheters that had recovered from anesthesia. In addition to demonstrating a clear and pronounced dose-dependent rise in arterial blood pressure upon repeated injections of boluses with ANG II (0.001-1 μg/kg), we demonstrate that the pressor response persisted following α-adrenergic blockade using the α-adrenergic antagonist phentolamine (2.5 mg/kg). Unfortunately, it proved impossible to block the ANG receptors using losartan (1, 3 or even 10 mg/kg). The pressor response to ANG II was associated with a significant rise in heart rate at the higher dosages, pointing to a resetting of the barostatic mechanism for heart rate regulation. The responses were similar in fasting and digesting pythons despite the expected rise in baseline values for blood pressure and heart rate of the digesting snakes. Copyright © 2020 Elsevier Inc. All rights reserved.

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