Biotelemetry transmitter implantation in rodents: impact on growth and circadian rhythms

Leon, Lisa R.; Walker, Larry D.; DuBose, David A.; Stephenson, Lou A.

doi:10.1152/ajpregu.00380.2003

Cited by 72 publications

(55 citation statements)

References 20 publications

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“…Animals were allowed to recover at least 1 wk after surgery. This has been shown to be sufficient (28) and was confirmed in our study group, where body weight returned to the preoperative value within 3 d after surgery. The Dataquest ART 2.1 Silver telemetry system (Data Sciences International) with RPC-1 receivers was used for telemetric measurement of SBP (mm Hg), MAP (mm Hg), DBP (mm Hg), HR (beats/min), and spontaneous locomotor action (SLA) in the animal house.…”

Section: Methodssupporting

confidence: 85%

“…Body weight was measured at regular intervals. Because surgery is known to influence body weight (28), only preimplantation weight data are used.…”

Section: Methodsmentioning

confidence: 99%

“…), shaved, and cleaned with chlorhexidine. Telemetry transmitters (TA11PA-C40, Data Sciences International, St. Paul, MN; body:transmitter size ratio ϭ 27:1 to 43:1 [28]) were implanted according to standard procedure (29). Briefly, a midline abdominal incision was made, and the aorta was exposed.…”

Section: Methodsmentioning

confidence: 99%

“…However, it is an invasive method and may therefore influence the results. To minimize these influences, transmitters were implanted at a time that the body:transmitter size ratio was in an acceptable range (28). Also, animals were allowed to recover for at least 1 week before measurements started.…”

mentioning

confidence: 99%

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Association of Birth Weight with Cardiovascular Parameters in Adult Rats During Baseline and Stressed Conditions

et al. 2006

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Low birth weight (LBW) due to intrauterine growth restriction (IUGR) in humans is associated with increased blood pressure (BP) in adulthood. In Western countries, IUGR is based on uteroplacental dysfunction. We used an animal model of uteroplacental dysfunction to evaluate this correlation. We hypothesize that IUGR increases baseline BP and alters the BP response to acute stress, which may explain BP differences in previous studies using stressful methods to obtain BP. IUGR was induced by bilateral uterine artery ligation in pregnant Wistar rats according to a modified method of Wigglesworth. BP was measured in the offspring using telemetry, allowing for unstressed measurements in conscious animals. Cardiovascular data were obtained at the age of 12 wk during baseline and acute olfactory stress induced by an ammonia gauze. Rats born after IUGR had a lower birth weight versus controls and did not completely catch up in weight. At baseline, systolic BP (SBP), mean arterial pressure (MAP), and pulse pressure (PP) were elevated in IUGR rats versus controls, by 8, 6, and 5 mm Hg, respectively. There was a strong negative correlation between birth weight and SBP and between birth weight and PP. During acute stress, there was a tendency to reach a higher peak in SBP and to need a longer period to recover in IUGR animals. We conclude that IUGR is associated with increased baseline BP. I UGR leads to LBW, which is linked to an increased risk of various chronic diseases in adulthood (1-4). Numerous studies have described the association between LBW and hypertension (for review, see Huxley et al. (5)). The pathways that may lead to a rise in BP are not fully understood (6 -18).Several previous authors have studied BP in growthrestricted animals (19). In these studies, BP is commonly measured indirectly using the tail-cuff method. This method entails restraining and preheating the animal, which leads to increased BP, heart rate (HR), and plasma levels of epinephrine and norepinephrine (20). In fact, restraints on laboratory animals have been used as a stressor (21). Results obtained from these studies should therefore be interpreted with caution. The described raised BP in IUGR animals might reflect a different stress response rather than a raised baseline BP.BP can be measured both directly as in a nonstressed manner by telemetry (20). Previously, only two reports using telemetry have addressed the effect of IUGR on BP in rats. Tonkiss et al. (22) found a small rise in baseline diastolic BP (DBP) but not in SBP in IUGR rats. They also described a marked difference in the response to acute stress with a greater increase in DBP and SBP in IUGR rats. Jansson and Lambert (23) found no evidence for BP elevation after IUGR. In these studies, different models for IUGR were used. For a review of currently applied IUGR models, see Holemans et al. (19). Tonkiss et al. (24) applied an IUGR model based on prenatal protein restriction, which might not be representative of the human situation. In Western countries, the lead...

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Section: Methodssupporting

confidence: 85%

“…Body weight was measured at regular intervals. Because surgery is known to influence body weight (28), only preimplantation weight data are used.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Association of Birth Weight with Cardiovascular Parameters in Adult Rats During Baseline and Stressed Conditions

et al. 2006

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“…The weight of the implantable biotelemetry unit is compatible with similar commercial devices, 12 represents ∼3% of the rat body weight, and it is well tolerated by the animals in agreement with other studies. 25 The operation of several biotelemetric systems, operating in the same room, was tested after reduction of the transmission distance by varying the antenna tuning and modifying the "synch" byte of the transmission packet.…”

Section: Discussionmentioning

confidence: 99%

Real-Time Monitoring of Brain Tissue Oxygen Using a Miniaturized Biotelemetric Device Implanted in Freely Moving Rats

et al. 2009

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A miniaturized biotelemetric device for the amperometric detection of brain tissue oxygen is presented. The new system, derived from a previous design, has been coupled with a carbon microsensor for the real-time detection of dissolved O 2 in the striatum of freely moving rats. The implantable device consists of a single-supply sensor driver, a current-to-voltage converter, a microcontroller, and a miniaturized data transmitter. The oxygen current is converted to a digital value by means of an analog-to-digital converter integrated in a peripheral interface controller (PIC). The digital data is sent to a personal computer using a six-byte packet protocol by means of a miniaturized 434 MHz amplitude modulation (AM) transmitter. The receiver unit is connected to a personal computer (PC) via a universal serial bus. Custom developed software allows the PC to store and plot received data. The electronics were calibrated and tested in vitro under different experimental conditions and exhibited high stability, low power consumption, and good linear response in the nanoampere current range. The in vivo results confirmed previously published observations on oxygen dynamics in the striatum of freely moving rats. The system serves as a rapid and reliable model for studying the effects of different drugs on brain oxygen and brain blood flow and it is suited to work with direct-reduction sensors or O 2 -consuming biosensors.Oxygen is the most important oxidative substrate for biochemical reactions and for the production of ATP in the brain. Tissue concentration of dissolved O 2 is regulated by the balance between blood supply and local utilization 1 and plays a key role in brain energy metabolism related to either glucose 2 or lactate 3 used as energy substrates.The electrochemical reduction of oxygen is a complex process which can occur on the sensor surface via two mechanisms. In the first, complete reduction occurs in a single step, without the formation of detectable intermediates: 4In the second mechanism, reduction of oxygen occurs in two steps with the formation of hydrogen peroxide as measurable intermediate: 4A wide variety of sensors have been used for direct-reduction of O 2 with the majority of measurements obtained using constant potential amperometry (CPA) at a noble metal microelectrode such gold 5 or platinum. 6 The use of carbon-based electrodes has been reported by several groups 7-9 and often they are preferred to Pt cathodes because of their in vivo stability and less surface poisoning. 9 Moreover, 10 µm Nafion-coated carbon fibers, coupled with fast scan voltammetry (FCV), have been used for the measurement of dissolved oxygen with a subsecond time resolution. 8 However, as previously discussed, 9 the ideal sensor size has to be greater than the dimension of blood capillaries (∼100 µm) for preventing direct blood sampling of dissolved oxygen. In this article we present a new oxygen sensor geometry (conical) particularly suited for in vivo applications, minimizing the tissue trauma related to the stereot...

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Characterising core body temperature response of free‐moving C57BL/6 mice to 1.95 GHz whole‐body radiofrequency‐electromagnetic fields

Sylvester,

Deng,

McIntosh

et al. 2024

Bioelectromagnetics

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The present study investigated the core body temperature (CBT) response of free‐moving adult male and female C57BL/6 mice, during and following a 2‐h exposure to 1.95 GHz RF‐EMF within custom‐built reverberation chambers, using temperature capsules implanted within the intraperitoneal cavity and data continuously logged and transmitted via radiotelemetry postexposure. Comparing RF‐EMF exposures (WBA‐SAR of 1.25, 2.5, 3.75, and 5 W/kg) to the sham‐exposed condition, we identified a peak in CBT within the first 16 min of RF‐EMF exposure (+0.15, +0.31, +0.24, +0.37°C at 1.25, 2.5, 3.75, and 5 W/kg respectively; statistically significant at WBA‐SAR ≥ 2.5 W/kg only), which largely dissipated for the remainder of the exposure period. Immediately before the end of exposure, only the CBT of the 5 W/kg condition was statistically differentiable from sham. Based on our findings, it is apparent that mice are able to effectively compensate for the increased thermal load at RF‐EMF strengths up to 5 W/kg. In addition, the elevated CBT at the end of the exposure period in the 5 W/kg condition was statistically significantly reduced compared to the sham condition immediately after RF‐EMF exposure ceased. This would indicate that measures of CBT following the end of an RF‐EMF exposure period may not reflect the actual change in the CBT of mice caused by RF‐EMF exposure in mice.

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Biotelemetry transmitter implantation in rodents: impact on growth and circadian rhythms

Cited by 72 publications

References 20 publications

Association of Birth Weight with Cardiovascular Parameters in Adult Rats During Baseline and Stressed Conditions

Association of Birth Weight with Cardiovascular Parameters in Adult Rats During Baseline and Stressed Conditions

Real-Time Monitoring of Brain Tissue Oxygen Using a Miniaturized Biotelemetric Device Implanted in Freely Moving Rats

Characterising core body temperature response of free‐moving C57BL/6 mice to 1.95 GHz whole‐body radiofrequency‐electromagnetic fields

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