© 1987 Oxford University Press
research-article |
Monitoring Guinea Pig Core Temperature by Telemetry during Inhalation Exposures
Department of Industrial Environmental Health Sciences, Graduate School of Public Health, University of Pittsburg Pittsburgh, Pennsylvania 15261
A temperature telemetry system was incorporated into an existing animal model for inhalation toxicology. This system facilitated continuous monitoring of guinea pig temperature dur ing inhalation exposures. Components of the system included Mini-Mitter temperature-controlled oscillators, AM receivers, and an IBM microcomputer. Software was developed to per form signal processing and filtering. Transmitters were calibrated and then sterilized and surgically implanted in the guinea pig peritoneum. Monitoring the baseline temperature of nine animals indicated a mean temperature of 38.6 ± 0.3°C. Guinea pigs were treated with agents to induce transient hypo- or hyperthermia. For the former, exposure for 3 hr to 7.8 ppm diphenyl methane-4,4'-diisocyanate resulted in a 3°C temperature decrease. The temperature was deter mined from 230 readings per animal per hour. Inhalation of 9 or 44 µg/m endotoxin for 6 hr induced hyperthermia with a 1.5°C maximum increase in core temperature at 4.8 hr. With endotoxin, an increase in respiratory rate was also noted and followed the same pattern as tem perature with a maximal increase of 52% occurring at 4.2 hr. The temperature telemetry system enabled continuous long-term monitoring of toxicant-induced hypothermia and pyrexia with out interruption of inhalation exposure or measurements of respiratory parameters.