Influence of the acute intoxication with salts of some heavy metals on hexobarbital sleep and hexobarbital metabolism.

The effect of acute intoxication with salts of ten heavy metals on hexobarbital sleep and the dependence of this effect on the time of application and the dose of the heavy metal are studied in experiments on male albino rats. Two hours after subcutaneous injection of toxic doses, only cobalt nitrate significantly prolongs hexobarbital sleep. Significant prolongation of the sleep is observed at the 24th hour in intoxication with CuSO4, CdSO4, Co(NO3)2, Pb(CH3COO)2, ZnSO4, NiSO4, while As2O3, HgCl2, Bi(NO3)2 and SnCl2 do not change it. All heavy metals (with the exception of NiSO4) prolong significantly hexobarbital sleep 96 hours after the intoxication. At the 24th hour after intoxication with salts of heavy metals, the hexobarbital level in the blood serum at the 30th min after its administration is significantly higher for Co(NO3)2, CdSO4, NiSO4, and it tends to be higher for CuSO4 and Pb(CH3COO)2. This, together with the significant inhibition of the hexobarbital-oxidizing enzyme system in the case of Cu, Co, Cd and Pb, suggests that in the case of these heavy metals potentiation of the hexobarbital sleep is largely due to inhibition of the hexobarbital metabolism. No significant prolongation of hexobarbital sleep or changes in hexobarbital metabolism are found in intoxication with Hg, As, Bi and Sn salts. The definitely lower hexobarbital level in the blood serum and brain at the waking moment, as well as the lower threshold hypnotic doses, suggest the interference of pharmacodynamic mechanisms at the level of the central nervous system in the prolongation of hexobarbital sleep after acute intoxication with CuSO4, CdSO4 and NiSO4.