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Cardiovascular effects of oral toluene exposure in the rat monitored by radiotelemetry
Citation:
GORDON, C. J., T. E. SAMSAM, W. M. OSHIRO, AND P. J. BUSHNELL. Cardiovascular effects of oral toluene exposure in the rat monitored by radiotelemetry. NEUROTOXICOLOGY AND TERATOLOGY. Elsevier Science Ltd, New York, NY, 29(2):228-235, (2007).
Impact/Purpose:
Toluene is a volatile organic compound (VOC) that can be toxic to the CNS and cardiovascular system. VOC’s are prevalent in urban air and are generated by several types of regulated sources but there is little information on the toxic effects of VOC’s on the cardiovascular system. This study used Radiotelemetric techniques to measure heart rate, blood pressure, and body temperature in unrestrained and undisturbed rats dosed with toluene. The observed tachycardic and hypertensive effects of toluene will be important data for the development of PBPK models for toluene exposure and in the design of susceptibility of the aged to VOC’s
Description:
Toluene is a hazardous air pollutant that can be toxic to the nervous and cardiovascular systems. The cardiotoxicity data for toluene come from acute studies in anesthetized animals and from clinical observations made on toluene abusers and there is little known on the response of the cardiovascular and other autonomic processes to graded doses of toluene. This study assessed the effects of toluene (0.4, 0.8, and 1.2 g/kg; gavage) on heart rate (HR), blood pressure, core temperature (Tc), and motor activity (MA) in unrestrained, male Long-Evans rats monitored by telemetry. Toluene doses of 0.8 and 1.2 g/kg elicited significant elevations in HR, characterized by a transient 100 beat/min increase in HR lasting one hour followed with a steady state tachycardia lasting > 6 hr. Overall, HR increased by 25 and 50 beats /min in the 0.8 and 1.2 g/kg groups, respectively. MA increased markedly in the 0.8 and 1.2 g/kg groups but the tachycardia persisted in spite of recovery of MA in the 0.8 g/kg group. There was a small (< 0.5 ºC) increase in Tc above controls in rats dosed with 0.8 g/kg toluene, whereas 1.2 g/kg toluene elicited a transient reduction in Tc followed by a small elevation lasting several hours. In a second study, rats were implanted with transmitters to monitor blood pressure (BP), and were administered toluene as in the first study. HR, Tc, and MA were also monitored. The tachycardic effects of toluene at 0.8 and 1.2 g/kg were associated with a rise in blood pressure. Doses of 0.8 and 1.2 g/kg elicited a mean BP elevation of 6 and 16 mmHg, respectively, for 7 hours post-dosing. The biphasic tachycardia to toluene suggests multiple sites for eliciting the cardiotoxic effects of this toxicant.
URLs/Downloads:
Cardiovascular effects of oral toluene exposure in the rat monitored by radiotelemetry