Brain level and synthesis of acetylcholine during exposure to vibration and organic-phosphorus and phenol-derived pesticides.

The experiments were carried out on white rats studying the quantity and synthesis of acetyl-choline in the cerebral cortex and brain stem during exposure to vibration (50 Hz, 2 mm) and noise (80 dB), noise alone, and pesticides, chlorfenwinfos (1.66 mg/kg), DNPP (5.83 mg/kg), and DNBP (6.66 mg/Kg). The pesticides were given separately to resting animals and to animals exposed to vibration and noise, as well as noise alone. Vibration reduced the content and raised the synthesis of acetylcholine only in the cerebral cortex. The effect of exposure to noise included reduced content and increased synthesis of acetylcholine in the brain stem. Chlorfenwinfos, DNPP and DNBP had a similar effect raising the level of acetylcholine in the cortex and brain stem and decreasing the ability of its synthesis. Simultaneous exposure of the rats to the action of pesticides, vibration and noise, or noise alone led to mutual abolishing of the effects produced by each to these factors on the content and ability of acetylcholine synthesis in brain tissue. In the discussion it is suggested that vibration and noise stimulate the cholinergic centres in the brain. A concept of a mechanical action of vibration on the brain tissue is discussed also. Besides that, it was tried to explain the mechanism of action of pesticides on the content of acetylcholine and its synthesis and the mutual abolition of the effects produced by pesticides and those of vibration and noise, and noise alone on the concentration and ability of acetylcholine synthesis in the brain.