Effect of an aqueous extract of black walnut (Juglans nigra) on isolated equine digital vessels.

This research article investigates the effects of an aqueous extract produced from black walnut on the contractions in isolated blood vessels from a horse’s digit. The study found that the black walnut extract didn’t cause contractions in these vessels on its own, but triggered a stronger response following the administration of epinephrine and hydrocortisone.

Methodology and Findings

• The researchers conducted this study based on an observation in a 13-year-old Quarter Horse. After consumption of a large volume of the black walnut extract, the horse developed Obel grade-3 laminitis – a painful and debilitating disease affecting the hoofs of horses.
• The scientists wanted to investigate if the black walnut extract could influence the contractility of equine digital vessels – critical for hoof health. For this, they created an aqueous extract that was made from the heartwood of black walnuts.
• The extracted liquid was introduced to isolated blood vessels from the horse’s digit under a highly controlled environment – maintained in Krebs bicarbonate buffer with 95% oxygen at 37°C.
• Contrary to their expectations, the black walnut extract didn’t directly cause contractile effects in the equine digital vessels.
• However, the extract considerably amplified the vessel contractions induced by the administration of epinephrine potentiated with hydrocortisone. This suggests the black walnut extract enhances the vasoconstrictive response to these substances.
• Interestingly, when the same methodologies were applied using aqueous extracts from the shavings of eastern white pine, eastern red cedar, and pin oak, no such enhanced effect on epinephrine-induced contractions was observed. This indicates that the activity is unique to the black walnut.

Significance

• The findings indicate that consumption of black walnut can potentially amplify the reactions in the blood vessels of a horse’s hoof when exposed to substances like epinephrine and hydrocortisone.
• Significantly, this reaction was not observed when the horse consumed other types of wood, suggesting that there is something unique to black walnut that induces these responses.
• These findings broaden our understanding of laminitis and may contribute to new treatments or preventative measures. However, more research is needed to investigate this further.