Evaluation of the effect of caffeine and nicotine on postnatal neurobehavioral and functional development in normally-fed and protein malnourished rats

ABSTRACT

The prevalence of tobacco smoking and coffee drinking place nicotine and caffeine among the most used licit drugs that possess psychostimulant properties and dependence liability. Protein malnutrition [PM] represents one of the world's major health problems. It impairs mental and neurobehavioral development especially during lactation and can interfere with the safety and efficacy of drugs. The purpose of this study was to evaluate the effect of caffeine and nicotine co-administration during lactation on development of physical signs, reflexes and sensory functions, as well as performance of the neonates in T-maze, in addition to their effect on liver and kidney functions. Influence of PM on these developmental, behavioral and biochemical measurements were also evaluated. Since birth animals were provided with either 20% [control diet] or 8% [low protein diet] casein diet. Both normally-fed [NF] and protein malnourished [PM] lactating dams were daily [24 days] co-administered caffeine [30 or 60 mg/kg, L.P] and nicotine [0.5 or 1.0 mg/kg, L.P]. All rat pups were examined daily for appearance of physical signs [pinna detachment, downy hair, incisor eruption, fur, ear and eye opening] and development of reflexes and sensory punctions [righting reflex, cliff avoidance, negative geotaxis 25°, palmer grasp, auditory startle, negative geotaxis 45° and vibrissa placing]. The results showed that caffeine [60 mg/kg] and nicotine [1.0mg/kg] coadminsitration significantly delayed appearance of physical signs and retarded the development of deflexed and sensory function in NF rat pups, it also decreased number of correct choices in T-maze. By continuing administration of caffeine and nicotine, the postnatal developmental retardation increased and occurred at the low doses. PM potentiated both physical and neurobehavioral developmental delayments as well as functional defects induced by caffeine and nicotine co-administration during lactation. Thus, lactating mothers should be advised to limit their caffeine intake and to avoid exposure to tobacco smoke especially in protein deficiency population