These studies were conducted to assess the effects of lead toxicity on exploratory behavior and running. Effects of lead on exploratory behavior and running speed in the shrew, Blarina brevicauda (Insectivora).

ABSTRACT

These studies were conducted to assess the effects of lead toxicity on exploratory behavior and running speed in the short-tailed shrew, Blarina brevicauda. Shrews from the experimental group received 25 mg/kg/day of lead acetate in their drinking water for a period of 90 days. Control subjects received sodium acetate. Exploratory behavior was determined using a computerized activity chamber where movements of test subjects broke infrared beams projected onto the floor of the apparatus. Time spent (sec) in exploration was recorded over eight 6-min intervals. Running speed (km/hr) was measured in a microprocessor-controlled rectangular racetrack fitted with photocell timers. With respect to time spent in exploration, there were significant differences between lead-exposed (20.5-23.9 sec per 6-min testing session) and control subjects (6.8-8.1 sec) after the sixth testing interval in the activity chamber. With respect to maximal running speed, control subjects ran significantly faster (mean 14.8 km/hr) than their lead-exposed counterparts (5.83 km/hr). Lead-exposed animals exhibited hyperactivity and increased random locomotor movements. They would frequently bump into the walls and their movements were more random. Controls typically ran along the racetrack in a straight line. These results represent the first data for the effects of lead exposure on exploratory behavior and running speed for shrews.