Pharmacology of narcotic analgesics in the horse: selective blockade of narcotic-induced locomotor activity.

This research investigates the impact of various drugs on the locomotor activity in horses, specifically when given narcotics like morphine and fentanyl. It shows that administrating naloxone or acepromazine can effectively block or reduce the locomotor effects of the narcotics, and tests other drugs for similar effects.

Objective of the Research

• The main objective of this research is to study the pharmacological interaction between narcotics (morphine and fentanyl) and different drugs that could influence the induced locomotor activity in horses.

Result Findings

• The study found that the administration of naloxone completely blocked the locomotor activity induced in horses given fentanyl. The locomotor stimulation caused by morphine was reduced by 75% with the use of naloxone.
• Acepromazine was also found to partially block the locomotor responses to fentanyl and morphine. Its effect peaked 30 minutes after administration and remained for more than 6 hours. However, it was associated with considerable respiratory depression when administered simultaneously with morphine.
• The study found no incremental effect on locomotor activity when fentanyl was administered with large doses of pentazocine, suggesting that pentazocine has both antagonist and agonist actions at the narcotic receptor.
• The research found that furosemide and phenylbutazone, at clinical dosages, did not influence the locomotor activities induced by fentanyl.

Implications of the Study

• This research provides an understanding of the effects of various drugs on narcotic-induced locomotor activity in horses. Such information is crucial for developing effective drugs protocols to control these activities in the clinical treatment of horses.
• The findings also provide insights into the pharmacological interplay between narcotics and other drugs, which can be useful in advancing our understanding of their functioning on a biochemical level. This could potentially lead to the development of more refined therapies utilizing these drugs.