Abstract
Objective: Elevated aggression and poor intelligence scores occur in children with BLLs (Blood Lead Levels) lower than 10 μg/dL while Pb-exposed cats show increased aggressive behavior with BLLs of 10 μg/dL. This increased aggression in cats may be associated with the development of hyper-spiny neurons observed in the motor cortex, hippocampus and cerebellum of kittens with BLLs<1.2 μg/dL. These results suggest that lead ingestion by kittens might result in learning and behavioral deficits similar to those observed in lead-burdened children. Methods: To test this, kittens were treated (20 mg/kg/day, lead acetate or distil water via esophageal intubation) from Postnatal Day (PND) 1 to 7. At 8 and 10 weeks of age, the kittens were tested in a reversal T-maze, an open-field, and a free-fall test. Results: 8 weeks old Pb-treated kittens showed a delay in learning as demonstrated by a significant higher number of Incorrect Arm Choices (IACs) in the T-maze that returned to control levels in 10 weeks old kittens. No differences occurred between the two groups at 8 and 10 weeks of age in the open-field or free-fall tests. Conclusion: The impairment in the reversal T-maze suggests a Pb-induced delay in learning, which compares favourably with current understanding of delayed learning in Pb-poisoned children.
Highlights
Results from clinical studies indicate that children with Blood Lead Levels (BLLs) of 10 μg/dL or greater have marked behavioral, neurological, and intellectual impairments
Since the cognitive functions of spatial learning and memory are dependent on the hippocampus and the apparent development of long-term potentiation (LTP), the changes in dendritic neuronal structure of the hippocampus and LTP need to be determined in the kitten following the Pb-treatment paradigm followed in this study
The effect of this Pb-treatment paradigm needs to be determined in both 8 weeks and 10-week old kittens to determine if any changes that occur relate to the cognitive changes observed in the present study
Summary
Children are more sensitive to toxic Pb effects, whether through acute or chronic exposure, due to their high rate of bone development, and rapid neural differentiation [1]. Results from clinical studies indicate that children with Blood Lead Levels (BLLs) of 10 μg/dL or greater have marked behavioral, neurological, and intellectual impairments. Children with BLLs of 10 μg/ dL or greater were shown to display diagnostic features of attention deficit and hyperactivity disorder [2-5], increased aggression [6], and non-adaptive classroom behavior [7]. Intellectual impairments were demonstrated by poor performances on the Wechsler Intelligence Scale for Children (WISC) and the WISC-Revised scale [5,7-9]. Pb toxicity (>10 μg/dL) serves as a diagnostic differential in children who present with physiological/neurological disturbances such as reduced stature and skeletal growth [10-13], increased seizure frequency [14,15], coma [15], and death [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
