Comparison of opioid and alpha-2 adrenergic receptor binding in horse and dog brain using radioligand autoradiography.
Abstract: To test the hypothesis that the distribution, density, and subtype of opioid and alpha (alpha)-2 adrenergic receptors within the central nervous system (CNS) are significantly different between horse and dog. Methods: Prospective experimental study. Methods: Three dogs (3 years of age) and three horses (2-5 years of age). Animals were opioid- and alpha-2 agonist-free at the time of euthanasia. Methods: Brain tissue was obtained at 126 days post-surgery from dogs and 72 days post-surgery from horses. The brains were removed, sectioned coronally into 1-cm slabs, frozen in methylbutane, which was cooled by liquid nitrogen, and stored at -70 degrees C. Receptor autoradiography was performed using established techniques. [3H]DAMGO, [3H]U-69593, and [3H]RX821002 were used for mu ( micro )-opioid, kappa (kappa)-opioid, and alpha-2 adrenergic-binding assays, respectively. Species differences were analyzed separately for each major brain region by repeated measures anova for subregions followed by Fisher's protected Latin square design (LSD). p < 0.05 was considered significant. Results: There was higher binding of micro -opioid receptors in the frontal cortex, left somatosensory cortex, colliculus (mid-brain), and granule cell layer of the cerebellum of horses than that of dogs. There was higher binding to kappa-opioid receptors in the frontal cortex of dogs compared to horses, whereas binding to kappa-opioid receptors in the cerebellum was higher in horses. Binding to alpha-2 adrenergic receptors in the mid-brain was significantly higher in dogs than in horses. There was higher binding of alpha-2 adrenergic receptors in the dorsomedial and dorsolateral periaqueductal grey of dogs as compared to that of horses. Conclusions: The results of this study show that the distribution of these receptors is different between horses and dogs. Further work is needed to understand the relevance of these differences to clinical responses to opioids and alpha-2 adrenergic agonists in these species.
Publication Date: 2003-09-23 PubMed ID: 14498849DOI: 10.1046/j.1467-2995.2003.00143.xGoogle Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study explores and compares how opioid and alpha-2 adrenergic receptors are distributed, dense, and their subtypes in the central nervous system of horses and dogs. The research reveals significant variations in the receptor types and locations between these two species, which calls for more studies to understand the clinical responses to opioids and alpha-2 adrenergic agonists in these species.
Methodology
- In the experiment, three dogs aged 3 and three horses aged 2-5, free from opioid and alpha-2 agonist, were euthanized.
- The harvested brain tissues were sectioned into 1cm slabs, frozen in methylbutane cooled with liquid nitrogen, and stored at -70 degrees Celsius.
- Traditional techniques of receptor autoradiography were used. Three types of binding assays were used: [3H]DAMGO for micro-opioid, [3H]U-69593 for kappa-opioid, and [3H]RX821002 for alpha-2 adrenergic receptors.
- Any species differences for every significant brain region were analyzed separately via repeated measures ANOVA for subregions followed by Fisher’s protected Latin square design.
- Any occurrence with a p-value of less than 0.05 was marked as significant.
Results
- The result showed significantly higher binding of micro-opioid receptors in the frontal cortex, left somatosensory cortex, mid-brain, and cerebellum granule cell layer of horses compared to dogs.
- Dogs had a higher kappa-opioid receptors binding in the frontal cortex compared to horses, whereas horses showed higher kappa-opioid receptors binding within the cerebellum.
- Alpha-2 adrenergic receptors binding in the mid-brain was found to be significantly more in dogs than horses. Also, the dorsomedial and dorsolateral periaqueductal grey of dogs had higher binding of alpha-2 adrenergic receptors compared to horses.
Conclusion
- This research explicitly shows that the distribution of opioid and alpha-2 adrenergic receptors varies significantly between horses and dogs. The unique variance in receptor distribution and type density could explain the distinctive effects of specific drugs across different species.
- The study underlines the importance of further investigation to understand the clinical bearing of these variations, particularly in determining responses to opioids and alpha-2 adrenergic agonists across species.
Cite This Article
APA
Hellyer PW, Bai L, Supon J, Quail C, Wagner AE, Mama KR, Magnusson KR.
(2003).
Comparison of opioid and alpha-2 adrenergic receptor binding in horse and dog brain using radioligand autoradiography.
Vet Anaesth Analg, 30(3), 172-182.
https://doi.org/10.1046/j.1467-2995.2003.00143.x Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA. phellyer@colostate.edu
MeSH Terms
- Animals
- Autoradiography / veterinary
- Brain / metabolism
- Dogs / metabolism
- Female
- Horses / metabolism
- Male
- Prospective Studies
- Radioligand Assay / veterinary
- Receptors, Adrenergic, alpha-2 / metabolism
- Receptors, Opioid / metabolism
- Sex Factors
Citations
This article has been cited 5 times.- Dmitrović P, Vanaga J, Dupont J, Franck T, Gougnard A, Detilleux J, Kovalcuka L, Salciccia A, Serteyn D, Sandersen C. Effect of Fentanyl Infusion on Heart Rate Variability and Anaesthetic Requirements in Isoflurane-Anaesthetized Horses. Animals (Basel) 2021 Oct 9;11(10).
- Steagall PV, Monteiro-Steagall BP, Taylor PM. A review of the studies using buprenorphine in cats. J Vet Intern Med 2014 May-Jun;28(3):762-70.
- Tana LM, Isaza R, Koch DE, Hunter RP. Pharmacokinetics and intramuscular bioavailability of a single dose of butorphanol in Asian elephants (Elephas maximus). J Zoo Wildl Med 2010 Sep;41(3):418-25.
- Wang JY, Huang J, Chang JY, Woodward DJ, Luo F. Morphine modulation of pain processing in medial and lateral pain pathways. Mol Pain 2009 Oct 13;5:60.
- Ambros B. Effect of pretreatment with hydromorphone or buprenorphine on thermal antinociception induced by fentanyl in awake cats. J Feline Med Surg 2016 Oct;18(10):818-25.
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