The effect of detomidine and its antagonism with tolazoline on stress-related hormones, metabolites, physiologic responses, and behavior in awake ponies.
Abstract: Six ponies were used to investigate the effect of tolazoline antagonism of detomidine on physiological responses, behavior, epinephrine, norepinephrine, cortisol, glucose, and free fatty acids in awake ponies. Each pony had a catheter inserted into a jugular vein 1 hour before beginning the study. Awake ponies were administered detomidine (0.04 mg/kg intravenously [i.v.]) followed 20 minutes later by either tolazoline (4.0 mg/kg i.v.) or saline. Blood samples were drawn from the catheter 5 minutes before detomidine administration (baseline), 5 minutes after detomidine administration, 20 minutes before detomidine administration which was immediately before the administration of tolazoline or saline (time [T] = 0), and at 5, 30, and 60 minutes after injections of tolazoline or saline (T = 5, 30, and 60 minutes, respectively). Compared with heart rate at T = 0, tolazoline antagonism increased heart rate 45% at 5 minutes. There was no difference in heart rate between treatments at 30 minutes. Blood pressure remained stable after tolazoline, while it decreased over time after saline. Compared with concentrations at T = 0, tolazoline antagonism of detomidine in awake ponies resulted in a 55% increase in cortisol at 30 minutes and a 52% increase in glucose at 5 minutes. The change in free fatty acids was different for tolazoline and saline over time. Free fatty acids decreased after detomidine administration. Free fatty acids did not change after saline administration. After tolazoline administration, free fatty acids increased transiently. Tolazoline tended to decrease sedation and analgesia at 15 and 60 minutes postantagonism. Antagonism of detomidine-induced physiological and behavioral effects with tolazoline in awake ponies that were not experiencing pain appears to precipitate a stress response as measured by cortisol, glucose, and free fatty acids. If antagonism of an alpha-agonist is contemplated, the potential effect on hormones and metabolites should be considered.
Publication Date: 1997-01-01 PubMed ID: 9123816DOI: 10.1111/j.1532-950x.1997.tb01467.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research investigates how the interplay between detomidine and tolazoline impacts physical responses, behavior, and certain hormone and metabolite levels in awake ponies. The focus is on determining whether the antagonism – or contrasting interaction – of tolazoline against detomidine generates a stress response.
Methodology
- The study was carried out on six ponies. Each was fitted with a catheter in a jugular vein an hour before the experiment commenced.
- Each pony was administered detomidine, followed 20 minutes later by either tolazoline or saline – a type of placebo.
- Blood samples were extracted from the ponies before and after both the detomidine and the tolazoline or saline. Time intervals for blood extraction were five minutes before detomidine administration, five minutes after detomidine administration, twenty minutes before detomidine (which also means immediately before tolazoline or saline), and at five, thirty, and sixty minutes post tolazoline or saline administration.
Findings
- Tolazoline increased the ponies’ heart rate by 45%, compared with the heart rate before it was administered.
- There was no discernible difference in heart rate half an hour after the administration of either tolazoline or saline.
- Tolazoline maintained stable blood pressure levels, whereas saline usage saw a decline in blood pressure over time.
- Tolazoline produced an increase in cortisol and glucose levels, by 55% and 52% respectively.
- Free fatty acids decreased post detomidine administration and maintained stable after saline administration, while they increased transiently after the use of tolazoline.
- The study found tolazoline decreased sedation and analgesia both 15 and 60 minutes after being administered.
Implications
- The study indicates the antagonism of detomidine with tolazoline in awake ponies appears to induce a stress response, as signified by changes in cortisol, glucose, and free fatty acid levels.
- If a similar antagonism is to be used in any application, consideration should be given to its likely impact upon hormones and metabolites.
Cite This Article
APA
Carroll GL, Matthews NS, Hartsfield SM, Slater MR, Champney TH, Erickson SW.
(1997).
The effect of detomidine and its antagonism with tolazoline on stress-related hormones, metabolites, physiologic responses, and behavior in awake ponies.
Vet Surg, 26(1), 69-77.
https://doi.org/10.1111/j.1532-950x.1997.tb01467.x Publication
Researcher Affiliations
- Department of Small Animal Medicine and Surgery, Texas A&M University, College Station, USA.
MeSH Terms
- Adrenergic alpha-Antagonists / administration & dosage
- Adrenergic alpha-Antagonists / pharmacology
- Animals
- Behavior, Animal / drug effects
- Behavior, Animal / physiology
- Blood Glucose / metabolism
- Blood Pressure / drug effects
- Blood Pressure / physiology
- Consciousness / physiology
- Dose-Response Relationship, Drug
- Drug Interactions
- Epinephrine / blood
- Fatty Acids, Nonesterified / blood
- Female
- Heart Rate / drug effects
- Heart Rate / physiology
- Horse Diseases / metabolism
- Horse Diseases / physiopathology
- Horse Diseases / psychology
- Horses / blood
- Horses / metabolism
- Horses / physiology
- Hydrocortisone / blood
- Hypnotics and Sedatives / administration & dosage
- Hypnotics and Sedatives / pharmacology
- Imidazoles / administration & dosage
- Imidazoles / pharmacology
- Injections, Intravenous
- Male
- Norepinephrine / blood
- Receptors, Adrenergic, alpha / drug effects
- Receptors, Adrenergic, alpha / physiology
- Stress, Physiological / metabolism
- Stress, Physiological / physiopathology
- Stress, Physiological / veterinary
- Time Factors
- Tolazoline / administration & dosage
- Tolazoline / pharmacology
Citations
This article has been cited 5 times.- Gehlen H, Jaburg N, Merle R, Winter J. Can Endocrine Dysfunction Be Reliably Tested in Aged Horses That Are Experiencing Pain?. Animals (Basel) 2020 Aug 14;10(8).
- Pakkanen SAE, de Vries A, Raekallio MR, Mykkänen AK, Palviainen MJ, Sankari SM, Vainio OM. Changes in energy metabolism, and levels of stress-related hormones and electrolytes in horses after intravenous administration of romifidine and the peripheral α-2 adrenoceptor antagonist vatinoxan. Acta Vet Scand 2018 May 9;60(1):27.
- Tabar JJ, Cruz AM. Cecal rupture in foals--7 cases (1996-2006). Can Vet J 2009 Jan;50(1):65-70.
- Kanda T, Hikasa Y. Neurohormonal and metabolic effects of medetomidine compared with xylazine in healthy cats. Can J Vet Res 2008 Apr;72(3):278-86.
- Ambrisko TD, Hikasa Y. The antagonistic effects of atipamezole and yohimbine on stress-related neurohormonal and metabolic responses induced by medetomidine in dogs. Can J Vet Res 2003 Jan;67(1):64-7.
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