Supported by funds from the Merck-Merial Student Scholars Program, LSU School of Veterinary Medicine Equine Health Studies Program, and the United States Department of Agriculture National Research Initiative.
Effects of Topical Nitroglycerine Patches and Ointment on Digital Venous Plasma Nitric Oxide Concentrations and Digital Blood Flow in Healthy Conscious Horses
Article first published online: 28 NOV 2005
Volume 34, Issue 6, pages 604–609, November 2005
How to Cite
GILHOOLY, M. H., EADES, S. C., STOKES, A. M. and MOORE, R. M. (2005), Effects of Topical Nitroglycerine Patches and Ointment on Digital Venous Plasma Nitric Oxide Concentrations and Digital Blood Flow in Healthy Conscious Horses. Veterinary Surgery, 34: 604–609. doi: 10.1111/j.1532-950X.2005.00094.x
Presented in part at the Equine Laminitis Research Meeting and Panel, Louisville, KY, July 24, 2004.
- Issue published online: 28 NOV 2005
- Article first published online: 28 NOV 2005
- Submitted October 2004; Accepted February 2005
- nitric oxide;
- digital blood flow;
Objective— To measure and compare palmar digital venous plasma nitric oxide (NO) concentrations and digital arterial blood flow after application of topical nitroglycerine (NTG).
Study Design— Experimental study.
Animals— Healthy adult horses (n=8).
Methods— Digital blood flow was measured by an ultrasonic Doppler flow probe surgically implanted around the medial palmar digital artery. Blood was collected from a catheter placed in the medial palmar digital vein for quantification of NO. NTG patches, NTG ointment or control patches were placed over the palmar digital vessels at the level of the fetlock. Two horses had an intra-arterial infusion of an NTG solution into the medial palmar digital artery in a pilot study.
Results— Digital arterial blood flow did not change significantly with application of the NTG patches, NTG ointment, or control patches. There were no statistically significant or biologically important changes in digital venous NO concentrations across time or between treated and control horses. In the pilot study, digital arterial blood flow and palmar digital venous NO concentrations increased with intra-arterial infusion of NTG.
Conclusions— In clinically healthy horses, digital arterial blood flow and digital venous plasma NO concentrations did not change significantly with application of the NTG patches/ointment. These treatments are unlikely to have an effect on the digital vasculature of laminitic horses, however, further investigation is warranted.
Clinical Relevance— Although NTG patches have been used as a method of decreasing vasomotor tone and improving digital blood flow in horses with laminitis, this study provides evidence in healthy conscious horses that this treatment is not effective in altering digital blood flow.