Partial protection from organophosphate-induced cholinesterase inhibition by metyrapone treatment.

Background: Organophosphates are cholinesterase (ChE) inhibitors with worldwide use as insecticides. Stress response, evidenced by a dramatic and relatively long-lasting (several hours) rise in the plasma glucocorticoid concentration is an integral element of the organophosphate (OP) poisoning symptomatology. In rodents, corticosterone (CORT) is the main glucocorticoid.

Neuroendocrine and behavioral response to amphetamine challenge after exposure to an organophosphorus pesticide.

Objectives: Exposure to various stressors is known to result in sensitization to psychostimulants, a state related to the psychostimulant dependence and addiction. It has been shown in some studies that the rise in corticosterone (CORT) concentration is indispensable for both the induction and the expression of behavioral sensitization. Therefore, it might be suspected that behavioral hyposensitivity to amphetamine (AMPH) is somehow related to a reduced CORT response to the psychostimulant subsequent to the chlorphenvinphos (CVP) intoxication.

Effects of stress pretreatment on the dynamics of blood cholinesterase activity after exposure to an organophosphorus pesticide in the rat.

A single i.p. administration of 1.

Contrasting effects of 4-week inhalation exposure to pseudocumene or hemimellitene on sensitivity to amphetamine and propensity to amphetamine sensitization in the rat.

Objectives: Some data suggest that increased behavioural sensitivity to psychostimulants may develop after exposure to volatile chemicals in common use. The purpose of the present experiment was to find out whether and in what way inhalation exposure to pseudocumene (PS) or hemimellitene (HM) at low concentrations alters behavioural sensitivity to the psychostimulant amphetamine (AMPH), and propensity to develop behavioural sensitization to AMPH.

Material And Methods: Adult male Wistar rats were exposed 6 h/day, 5 days a week for 4 weeks to PS or HEM at 0, 25, 100 or 250 ppm.

Neurobehavioural functions in adult progeny of rat mothers exposed to methylmercury or 2,2', 4,4', 5,5'-hexachlorobiphenyl (PCB 153) alone or their combination during gestation and lactation.

Objectives: Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants. Both are neurotoxic, especially for the developing brain. The main source of human exposure to MeHg and PCBs is seafood.