EFFECT OF CENTRAL ACUTE ADMINISTRATION OF CADMIUM ON DRINKING BEHAVIOR

The effect of acute third ventricle cadmium administration on the drin king behavior of adult male rats under different situations was studie d. Injections of cadmium chloride (0.07, 0.7, and 7.0 ng/rat) signific antly attenuated water intake in dehydrated rats. Drinking behavior in duced by acute intracerebroventricular injections of carbachol (2 mu g /rat) or angiotensin II (5 ng/rat) was also inhibited by central cadmi um injections. Cadmium-induced blockade in water intake in dehydrated animals was reverted by the previous administration of a 5-HT2, antago nist (RP62203) in different doses (5 and 10 mu g/rat). The data clearl y reveal that cadmium elicits very fast actions on the central nervous system. It is suggested that cadmium-induced attenuation of water int ake may rely on at least three different mechanisms: impairment of cho linergic and angiotensinergic systems in the brain and stimulation of a central serotonergic drive acting on 5-HT, receptors. The study of c admium neurotoxicity by observation of drinking behavior, a behavioral parameter easy to be recorded and measured, is proposed.