Effects of caffeine on locomotor activity of horses: determination of the no-effect threshold.
Abstract: Caffeine is the legal stimulant consumed most extensively by the human world population and may be found eventually in the urine and/or blood of race horses. The fact that caffeine is in foods led us to determine the highest no-effect dose (HNED) of caffeine on the spontaneous locomotor activity of horses and then to quantify this substance in urine until it disappeared. We built two behavioural stalls equipped with juxtaposed photoelectric sensors that emit infrared beams that divide the stall into nine sectors in a 'tic-tac-toe' fashion. Each time a beam was interrupted by a leg of the horse, a pulse was generated; the pulses were counted at 5-min intervals and stored by a microcomputer. Environmental effects were minimized by installing exhaust fans producing white noise that obscured outside sounds. One-way observation windows prevented the animals from seeing outside. The sensors were turned on 45 min before drug administration (saline control or caffeine). The animals were observed for up to 8 h after i.v. administration of 2.0, 2.5, 3.0 or 5.0 mg caffeine kg(-1). The HNED of caffeine for stimulation of the spontaneous locomotor activity of horses was 2.0 mg kg(-1). The quantification of caffeine in urine and plasma samples was done by gradient HPLC with UV detection. The no-effect threshold should not be greater than 2.0 microg caffeine ml(-1) plasma or 5.0 microg caffeine ml(-1) urine.
Copyright 2001 John Wiley & Sons, Ltd.
Publication Date: 2001-06-19 PubMed ID: 11404835DOI: 10.1002/jat.748Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research explored the effects of caffeine on the locomotor activity of race horses, identifying the maximum dose that has no impact on the animals’ spontaneous movement. The study found that dosages of caffeine above 2.0 mg/kg increase spontaneous locomotion, and suggests that permissible caffeine levels in plasma and urine should not exceed 2.0 microg/ml and 5.0 microg/ml respectively.
Experimental Setup
- The researchers conducted the study in two specially designed behaviour stalls. Each stall was partitioned into nine segments using infrared beams. When a horse interrupted a beam with its leg, the interruption was recorded, allowing for the quantification of movement.
- In order to limit external influences on the horses’ movement, the setup included exhaust fans producing white noise to mask other sounds, and one-way observation windows to prevent the animals from viewing the outside world.
Data Collection
- For 45 minutes before administering a dose of caffeine, the researchers monitored the horses’ spontaneous locomotor activity as a baseline measurement.
- Each horse was then given an intravenous dose of one of four caffeine concentrations. The doses varied between 2.0 and 5.0 mg of caffeine per kg of body weight. The movement activity was observed and recorded for eight hours post-administration.
- The team also collected urine and plasma samples from the horses for concentration analysis of caffeine. This was performed using gradient High-Performance Liquid Chromatography (HPLC) with UV detection.
Findings
- The research determined that a dose of 2.0 mg of caffeine per kg of body weight was the Highest No-Effect Dose (HNED) on spontaneous locomotor activity in horses. Any dosage above this threshold stimulated activity.
- From the sample testing, the researchers proposed that the no-effect threshold for caffeine should not exceed 2.0 microg/ml in plasma and should not exceed 5.0 microg/ml in urine.
Cite This Article
APA
Queiroz-Neto A, Zamur G, Carregaro AB, Mataqueiro MI, Salvadori MC, Azevedo CP, Harkins JD, Tobin T.
(2001).
Effects of caffeine on locomotor activity of horses: determination of the no-effect threshold.
J Appl Toxicol, 21(3), 229-234.
https://doi.org/10.1002/jat.748 Publication
Researcher Affiliations
- Departamento de Morfologia e Fisiologia Animal, Faculdade de Ciências Agrárias e Veterinárias, Câmpus de Jaboticabal, FCAV/UNESP, 14884-900 Jaboticabal, SP, Brazil. aqueiroz@fcav.unesp.br
MeSH Terms
- Animals
- Caffeine / pharmacology
- Caffeine / urine
- Central Nervous System Stimulants / pharmacology
- Central Nervous System Stimulants / urine
- Chromatography, High Pressure Liquid
- Female
- Horses
- Locomotion / drug effects
- No-Observed-Adverse-Effect Level
- Sensitivity and Specificity
- Urinalysis / veterinary
Citations
This article has been cited 1 times.- Delfiol DJ, Oliveira-Filho JP, Casalecchi FL, Kievitsbosch T, Hussni CA, Riet-Correa F, Araujo JP Jr, Borges AS. Equine poisoning by coffee husk (Coffea arabica L.).. BMC Vet Res 2012 Jan 12;8:4.
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