The effects of naloxone on endotoxic and hemorrhagic shock in horses.
Abstract: The effects of naloxone on the cardiovascular, hematologic and metabolic derangements associated with endotoxic and hemorrhagic shock were studied in unanesthetized horses. In the first of 3 experiments blood glucose and lactate levels, hematocrit, white, red and differential white cell counts, rectal temperature and clinical signs were obtained before and after endotoxin (10 micrograms/Kg) administration in 5 horses. In the second experiment, two groups of 3 horses received either intravenous naloxone (0.04 mg/Kg) or saline, 7 minutes prior to endotoxin. In a third experiment two groups of 4 horses received either saline or naloxone (0.20 mg/Kg) immediately following acute hemorrhage. In the second and third experiments, pulse, mean arterial and right ventricular pressures, and heart rate were also observed. Endotoxin and acute hemorrhage produced hypothermia, leukopenia, lymphopenia, neutropenia, elevations in hematocrit, blood glucose and blood lactate, and clinical signs of shock. Naloxone (0.040 mg/Kg IV) significantly lowered endotoxin-induced increases in right ventricular pressure and heart rate, and at a higher dose (0.20 mg/Kg) antagonized the decrease in pulse and heart rate, and tachycardia observed after acute hemorrhage. These results suggest endogenous opioids are involved in the pathogenesis of shock. Naloxone appeared to attenuate some of the cardiovascular responses associated with shock and thus may be of therapeutic value in shock management.
Publication Date: 1984-05-01 PubMed ID: 6739953
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- Non-P.H.S.
Summary
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This research article assesses how naloxone, a medication used to counteract opioid effects, influences cardiac, hematological, and metabolic irregularities related to endotoxic and hemorrhagic shock in unanesthetized horses. The study revealed that naloxone can moderate some cardiovascular responses associated with shock, suggesting it might have a therapeutic application in shock treatment.
Overview of The Research Study
- The research project divided into three experiments. The initial experiment examined blood glucose and lactate levels, hematocrit, white, red and differential white cell counts, rectal temperature, and clinical symptoms before and after administering endotoxin to the horses.
- In the second experiment, two groups of horses received either naloxone or saline intravenously seven minutes before endotoxin was administered. The aim was to examine how pre-treatment with naloxone could affect the horses’ response to induced toxic shock.
- In the final experiment, two groups of horses received either naloxone or saline post acute hemorrhage. The study aimed to observe the influence of naloxone on the body’s response to severe blood loss.
Observed Effects of Endotoxin and Acute Hemorrhage
- Endotoxin and acute hemorrhage resulted in hypothermia, leukopenia (a decrease in the number of white blood cells), lymphopenia (reduced lymphocyte levels), and neutropenia (a drop in the number of neutrophils).
- These circumstances also led to increases in hematocrit (the ratio of red blood cells to total blood volume), blood glucose, and blood lactate, and flagged clinical indications of shock.
Effects of Naloxone intervention
- Naloxone treatment substantially decreased the endotoxin-induced surge in right ventricular pressure and heart rate, suggestive of a beneficial effect in managing shock symptoms.
- At a higher dosage, naloxone counteracted the decrease in pulse and heart rate and tachycardia (abnormally rapid heart rate) noticed after acute hemorrhage. These observations indicate that naloxone can stabilize heart-related parameters under shock conditions.
- The results from this series of experiments suggest that endogenous opioids (substances produced in the body that behave like opiate drugs) play a role in developing shock. As naloxone blocks the effects of opioids, it seems to alleviate some of the cardiovascular responses associated with shock. Thus, naloxone may potentially have value in treating shock.
Cite This Article
APA
Weld JM, Kamerling SG, Combie JD, Nugent TE, Woods WE, Oeltgen P, Tobin T.
(1984).
The effects of naloxone on endotoxic and hemorrhagic shock in horses.
Res Commun Chem Pathol Pharmacol, 44(2), 227-238.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Blood Pressure / drug effects
- Disease Models, Animal
- Endotoxins / toxicity
- Female
- Heart Rate / drug effects
- Hemodynamics / drug effects
- Horses / physiology
- Male
- Naloxone / pharmacology
- Naloxone / therapeutic use
- Pulse / drug effects
- Shock, Hemorrhagic / drug therapy
- Shock, Hemorrhagic / physiopathology
- Shock, Septic / drug therapy
- Shock, Septic / physiopathology
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