Dehydration accelerates in vivo platelet aggregation in pial arterioles of lead-treated mice

Effect of water deprivation for 24 h on platelet aggregation in pial arterioles of lead-treated mice was investigated. Exposure to lead was made by i.p. injections for 24 h of lead accetate dissolved in a 5% glucose solution, vehicle. Three doses of lead were used, a low dose of 0.1 mg/kg, intermediate dose of 0.5 mg/kg and a high dose of 1,0 mg/kg. Adult male mice were divided into four groups, 10 each. Platelet aggregation in pial microvessels was induced photochemically, in vivo, in anesthetized (urethane, 1-2 mg/g, i.p.) animals by activation of circulating sodium fluorescein (0.1 ml of 5% solution/25g, i.v.) with an intense mercury light. The time required for the first platelet aggregate to appear in pial arterioles was significantly (P<0.05) shorter (166±27, 154±58, 218±68 sec; in low, intermediate and high doses of lead, respectively) than in control (276±63 sec). Dehydration significantly reduced both the time required for the first platelet aggregate (61±21 vs 125±31 sec) and the time to full occlusion (134±18 vs 239±69 sec, lead-treated vs control, P<0.05). These data revealed that lead can exert its effect on cerebrovascular thrombosis after 24 h of exposure and such can be enhanced under water deprivation conditions.