Institut for Biologi

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Line Mathilde Brostrup Hansen

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

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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.

OriginalsprogEngelsk
Artikelnummer110839
TidsskriftComparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology
Vol/bind252
ISSN1095-6433
DOI
StatusUdgivet - feb. 2021

Bibliografisk note

Funding Information:
T.W. is supported by the Danish Natural Science Research Council and was a recipient of a Skou-fellowship from Aarhus Institute of Advanced Sciences (AIAS) when this study was performed.

Publisher Copyright:
© 2020 Elsevier Inc.

Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.

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