Nitric oxide synthase inhibition reveals differences in the nitric oxide pathway in previously laminitic ponies.
Abstract: Previously laminitic (PL) ponies are reported to have higher blood pressure than non laminitic (NL) ponies. This relative hypertension may be related to endothelial cell dysfunction, similar to humans with metabolic syndrome. To investigate the relationship between laminitis predisposition and endothelial dysfunction, the effect of nitric oxide synthase (NOS) inhibition on the change in circulating nitric oxide (NO) concentrations and systemic blood pressure (BP) was determined. An intravenous NO sensor was used to measure changes in blood NO concentration during and after intravenous infusion of the NOS inhibitor L-nitroarginine methyl ester (L-NAME; 4 mg/kg IV) in PL and NL ponies. NO concentrations decreased and BP increased in response to L-NAME infusion, with a significantly (p = 0.02) greater rate of increase in systolic BP in PL (14.62 ± 1.88 mmHg/h) compared to NL (8.54 ± 1.88 mmHg/h) ponies. This greater effect on BP in PL compared to NL ponies is consistent with higher basal NO production in PL ponies, suggesting that the relative hypertension previously seen in PL ponies results in increased basal NO production, rather than being caused by reduced NO production as hypothesised. Up-regulation of the NO system may be a compensatory mechanism stimulated by the higher resting BP in PL ponies. Further investigation of the mechanism underlying the relative hypertension seen in PL ponies is required.
Copyright © 2022 Mars Horsecare UK Limited, The Author(s). Published by Elsevier Ltd.. All rights reserved.
Publication Date: 2022-07-01 PubMed ID: 35809416DOI: 10.1016/j.rvsc.2022.05.012Google Scholar: Lookup
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- Journal Article
Summary
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The research article analyzes the possible relationship between laminitis susceptibility in ponies and endothelial dysfunction, by studying the effects of nitric oxide synthase (NOS) inhibition on nitric oxide (NO) concentrations and systemic blood pressure (BP). It concludes that the relative hypertension seen in previously laminitic (PL) ponies may cause increased nitric oxide production, suggesting a compensatory mechanism.
Research Method
- The paper investigates the connection between predisposition to laminitis, a condition in horses that affects their hooves, and endothelial dysfunction, that is commonly linked to metabolic syndrome in humans.
- In order to delve into this relationship, the researchers introduce an inhibitor to nitric oxide synthase (NOS), an enzyme that catalyses the production of nitric oxide (NO), which is key in regulating blood pressure.
- They use an intravenous NO sensor to monitor changes in blood NO concentration during and after the introduction of the NOS inhibitor, L-nitroarginine methyl ester (L-NAME).
- This experiment is carried out on two separate groups — previously laminitic (PL) ponies and non-laminitic (NL) ponies — to observe the different reactions.
Research Findings
- NO concentrations decreased and blood pressure increased in response to the infusion of L-NAME.
- Significantly, the rate of increase in systolic blood pressure was greater in PL ponies compared to NL ponies.
- This greater effect on BP in PL compared to NL ponies indicates higher basal NO production in PL ponies, contrary to the initial hypothesis of reduced NO production causing the relative hypertension in PL ponies.
Conclusion
- The research suggests that an overactive NO system, working as a compensatory mechanism to balance the high resting BP, could be the cause for the relative hypertension seen in PL ponies.
- It underscores the need for further investigation into the mechanisms underlying the hypertension observed in PL ponies.
Cite This Article
APA
Finding EJT, Elliott J, Harris PA, Menzies-Gow NJ.
(2022).
Nitric oxide synthase inhibition reveals differences in the nitric oxide pathway in previously laminitic ponies.
Res Vet Sci, 150, 79-82.
https://doi.org/10.1016/j.rvsc.2022.05.012 Publication
Researcher Affiliations
- Department of Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK. Electronic address: efinding@rvc.ac.uk.
- Department of Comparative Biological Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, UK.
- Waltham Petcare Science Institute, Leicestershire, UK.
- Department of Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK.
MeSH Terms
- Animals
- Blood Pressure
- Dermatitis / veterinary
- Horse Diseases
- Horses
- Humans
- Hypertension / veterinary
- NG-Nitroarginine Methyl Ester / pharmacology
- Nitric Oxide / metabolism
- Nitric Oxide Synthase / metabolism
- Nitric Oxide Synthase / pharmacology
Citations
This article has been cited 1 times.- Liu C, Wang X, Parris C, Pang Q, Naeem MU, Wang L. Macula Densa Nitric Oxide Synthase 1 Controls Renin Release and Renin-Dependent Blood Pressure Changes. Discov Med 2023 Aug;35(177):525-532.
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