Blocking of repetitive response from a neuromuscular preparation of Tenebrio Molitor by phosphotriesters

Abstract

1. Diethylphosphate esters of m-cresol, o-, m- and p-nitrophenols, 2-nitro- p-, 4-nitro- m- and 5-nitro- o-cresols, thymol, 3,5-xylenol, α-naphthol, p-hydroxybiphenol, p-cyanophenol, p-chlorophenol and 3,4,5-trichlorophenol were synthesized and tested for their inhibitory activity toward the neuromuscular preparation of meal worm. T. molitor. 2. Remarkable depression of excitatory postsynaptic potentials (EPSPs), possibly due to acetylcholinesterase inhibition, was observed to occur by p-nitrophenol, 2-nitro- p-cresol, p-chlorophenol and 3,4,5-trichlorophenol derivatives of diethylphosphate ester, each at a concentration from 10 −5−10 −6M. 3. The spontaneous repetitive miniature end-plate potentials (MEPPs) on a post synaptic membrane was predominantly induced by p-cyanophenol, m-cresol, 4-nitro- m- and 5-nitro- o-cresols esters of the diethylphosphate. Following inducement of the spontaneous excitation, neural transmission was blocked completely.