Triethyl and trimethyl lead: effects on behavior, CNS morphology and concentrations of lead in blood and brain of rat.

The dose-related behavioral effects produced by triethyl (TEL) (2.6 to 7.9 mg/kg) and trimethyl lead (TML) (8.8 to 26.2 mg/kg) were assessed 2, 7, 14, 21 and 28 days following injection. TEL, but not TML, produced dose- and time-related decreases in body weight. Both agents decreased vertical and horizontal components of motor activity 2 days postdosing; increased activity was seen consistently in TEL-exposed rats 7 to 21 days after dosing. TML increased fore- and hindlimb strength for up to 28 days postdosing. TEL had no consistent effect on this measure. Both TEL and TML decreased responsiveness to an acoustic stimulus during the first two weeks postdosing. Latency to respond to a thermal stimulus was increased 2 to 14 days after TEL with the peak change occurring from 2 to 7 days. The peak of effect following TML was two weeks postdosing. In general, there was a significant correlation between both TEL and TML-induced changes in blood and brain lead levels and decreased sensitivity to a thermal stimulus. The apparent delayed onset of TML-induced neurobehavioral effects may be related to a longer time to obtain peak blood or brain levels. Histopathological assessment of rats 7 or 28 days after TEL and TML indicated that TEL caused structural abnormalities in the hippocampus and dorsal root ganglion, while TML produced changes primarily in the spinal cord and brain stem.