Brain catecholamine metabolism changes and hypothermia in intoxication by anticholinesterase agents.

Sublethal doses of physostigmine, paraoxon and soman induce a short-lasting fall in rat core temperature potentiated by alpha-methyl-para-tyrosine (alpha-MT) (early effects). When the own hypothermic effect of the anticholinesterase agent has disappeared (late effects), alpha-MT induces a new decrease in temperature. Parallel biochemical studies of catecholamine levels and turnover were performed in several brain areas. The norepinephrine (NE) turnover is generally increased particularly in the hypothalamus, suggesting that NE hypothalamic changes might be linked to a latent perturbation of thermoregulatory mechanisms. Furthermore, it was shown that soman acts differently from the other drugs by inducing quite important changes in both NE and dopamine levels.