ACTION OF THE HERBICIDE BUTACHLOR ON CHOLINESTERASES IN THE FRESH-WATER SNAIL PILA-GLOBOSA (SWAINSON)

Butachlor action on acetylcholinesterase (AChE) and butyrylcholinester ase (BuChE) activities in central nervous tissue of the snail Pila glo bosa was assayed following the method of ELLMAN et al(1) in vitro by a dding butachlor directly (10-100 mu moles), to tissue homogenates and in in vivo by exposing the snails to sub-lethal concentration (26.6 pp m) and taking out the tissue for experimentation at different interval s (3,6,12,24 and 48 h) of exposure. The enzyme activities decreased in a dose-dependent manner in vitro, and up to 12-24 h in vivo after whi ch they showed recovery towards the control. The inhibition of choline sterases by butachlor in vitro indicates a direct action of the herbic ide on these enzymes. Presumably butachlor exercises its neurotoxic ef fects through cholinergic impairment in a way similar to that of organ ophosphates and carbamates.