Browsing by Subject "Telemetry"

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    Characterization of the relationship between spontaneous locomotor activity and cardiovascular parameters in conscious freely moving rats
    (Elsevier, 2016-02) Zaretsky, Dmitry V.; Zaretskaia, Maria V.; DiMicco, Joseph A.; Department of Emergency Medicine, IU School of Medicine
    In freely behaving rats, variations in heart rate (HR) and blood pressure (BP) are coupled closely with changes in locomotor activity (Act). We have attempted to characterize this relationship mathematically. In 10- and 16-week-old rats, HR, BP and Act were recorded telemetrically every minute for 2 days under 12h:12h light-dark cycling. After examining data for individual rats, we found that the relationship between Act and HR could be approximated by the negative exponential function HR(Act)=HRmax-(HRmax-HRmin)∗exp(-Act/Acte), where HRmax, HRmin, and Acte are constants. These constants were calculated separately for light and dark periods by non-linear curve fitting. HR corresponding to maximal locomotion was similar during the light and dark phases, while HR at rest during the dark phase was higher than during the light phase. The range of HR variability associated with Act during the dark phase was similar in young and older animals, but minimal HR was significantly lower in older rats. The relationship between Act and BP was approximated with a similar function. We have found no differences between BP at rest and at maximal locomotion between light and dark and between 10-week and 16-week-old rats. Our results indicate that in rats, cardiovascular parameters are coupled to locomotion to a high degree; however both the HR and the BP reach maximal values when locomotor activity is relatively low. We also found that the phase of daily cycle affects HR in conscious rats independent of locomotor activity.
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    Impact of Opioid and Nonopioid Drugs on Postsurgical Pain Management in the Rat
    (Hindawi Publishing Corporation, 2016) Wilson, Natalie M.; Ripsch, Matthew S.; White, Fletcher A.; Department of Anesthesia, IU School of Medicine
    Aim. Nonsteroidal anti-inflammatory drugs or opioids are commonly used to control surgical pain following veterinary and clinical procedures. This study evaluated the efficacy of postoperative ketorolac or buprenorphine following abdominal surgery. Main Methods. Mean arterial pressure (MAP), heart rate, animal activity, corticosterone levels, and a nociceptive sensitivity assay were used to evaluate 18 adult male Sprague-Dawley rats which underwent aortic artery occlusion for implantation of a radiotelemetry device. The animals were treated postoperatively with intraperitoneal injections of vehicle, ketorolac (10 mg/kg), or buprenorphine (0.06 mg/kg) every 8 hours for 3 days. Key Findings. There were no consistent significant changes in any of the telemetry parameters after treatment with ketorolac compared with no saline treatment with the exception of increased MAP in the buprenorphine group during the first 48 hours when compared with other treatment groups. There was a sustained increase in fecal corticosterone levels from baseline on days 2-7 with buprenorphine compared with vehicle- or ketorolac-treated animals. All treatment conditions displayed reduced paw withdrawal thresholds (PWTs) from day 1 to day 21 following surgery. Compared with the vehicle treatment group, buprenorphine-treated animals exhibited significantly lower PWT levels from day 4 to 14 days. Significance. Given the prolonged increase in fecal corticosterone levels and pronounced changes in tactile hyperalgesia behavior in rodents subjected to buprenorphine treatment, these data suggest that ketorolac may be superior to buprenorphine for the treatment of postprocedure pain behavior in rodents.