EFFECT OF LEAD ACETATE ON NEUROBEHAVIORAL DEVELOPMENT OF RATS

We investigated the effects of lead exposure during the pre-and postna tal period on the neurobehavioral development of female Wistar rats (7 0-75 days of age, 120-150 g) using a protocol of lead intoxication tha t does not affect weight gain. Wistar rats were submitted to lead acet ate intoxication by giving their dams 1.0 mM lead acetate. Control dam s received deionized water. Growth and neuromotor development were ass essed by monitoring daily the following parameters in 20 litters: body weight, ear unfolding, incisor eruption, eye opening, righting, palma r grasp, negative geotaxis, cliff avoidance and startle reflex. Sponta neous alternation was assessed on postnatal day 17 using a T maze. The animals' ability to equilibrate on a beaker rim was measured on postn atal day 19. Lead intoxication was confirmed by measuring renal, hepat ic and cerebral lead concentration in dams and litters. Lead treatment hastened the day of appearance of the following parameters: eye openi ng(control: 13.5 +/- 0.6, N = 88; lead: 12.9 +/- 0.6, N = 72; P<0.05), startle reflex(control: 13.0 +/- 0.8, N = 88; lead: 12.0 +/- 0.7, N = 72; P<0.05) and negative geotaxis. On the other hand, spontaneous alt ernation performance was hindered in lead-exposed animals (control: 37 .6 +/- 19.7; lead: 57.5 +/- 28.3% of alternating animals; P<0.05). The se results suggest that lead exposure without concomitant undernutriti on alters rat development, affecting specific subsets of motor skills.