Responses of Cholinergic and Noncholinergic Renshaw Cell Receptors After Acute and Chronic Exposure to Anticholinesterases

摘要

Investigation of cat lumbar 7 segment (L-7) ventral horn cells (motoneurones and interneurones-Renshaw cells) in the presence of excess acetylcholine (ACh) are being studied as models of a central cholinergic transmitting synapse. Preliminary studies to investigate effects induced by chronic low dose exposure to diisopropylfluorophosphate (DFP) have begun with a two week exposure to diisopropylfuorophosphate (DFP) have begun with a two week exposure protocol with DFP doses of 0.1, 0.2, 0.5, 0.75, and 1.0 mg/kg/day s.c. Cats tolerate doses of 0.1 to 0.5 mg/kg/day s.c. with symptoms of increased defecation, moderate constriction of pupils slight ataxia and weight loss. The degree of severity increases with dose. Renshaw cell unit potentials (RUP) and their field potentials (RFP) are being studied to determine effects from exposure to DFP in doses according to the protocol above. In control animals, RFP respond similar to RUP during and subsequent to repetitive stimulation. Effects of drug treatment on the ventral horn neurones of L-7 are being studied with light microscopy (LM) and electron microscopy (EM) histochemistry.