Lignocaine: inhibitory effect on synaptosomal and erythrocyte membrane-bound acetylcholinesterase activity.

Lignocaine (5-20 mM) reversibly inhibits (in vitro) AChE activity of rat brain synaptosome (33-66%) and erythrocyte membrane (10-54%) in a concentration dependent manner. Lineweaver-Burk plots indicate that lignocaine-induced inhibition of AChE activity in synaptosome is competitive, whereas in erythrocyte membrane inhibition of AChE is non-competitive in nature. Arrhenius plots show that transition temperatures of both synaptosomal and erythrocyte membrane-bound AChE are significantly reduced in the presence of lignocaine. These results suggest that lignocaine increases the lipid fluidity of synaptosomal and erythrocyte membrane which may be a cause of inhibition of membrane-bound AChE activity.