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).

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.

Follicular growth rate and lack of influence of oestradiol valerate, testosterone propionate and aminoglutethimide phosphate on ovarian follicular development in the musk shrew, Suncus murinus L.

Growth rate of follicles and effects of administration of oestradiol valerate (EV), testosterone propionate (TP) and aminoglutethemide phosphate (AGP) on the development of ovarian follicles of the adult musk shrew were investigated. The follicular growth rate was estimated by mitotic index before and 2 hr after colchicine treatment to the shrews. Mitotic index of granulosa cells increased linearly with the increase in the follicular diameter. The calculated mean duration of mitosis was 0.48 hr. The mean time taken for follicle to pass from primary follicle stage to preovulatory stage was estimated to be 12 days. Treatment of both the steroids EV and TP, failed to produce any noticeable effect on the atretic follicle of the musk shrew. The results indicate that neither EV or TP, nor the potent steroid inhibitor AGP had any influence on the growth of large follicles in this primitive eutherian mammal.