| Abstract: | The effects of combinations of plant‐derived molluscicides with piperonyl butoxide (PB) or ENT 8184 (MGK‐264) were studied on different enzyme activities and biogenic amine levels in the nervous tissue of Limnaea acuminata. 24‐h in vivo exposure of the nervous tissue of L acuminata to 40% and 80% of the 24‐h LC50 of the plant‐derived molluscicides Azadirachta indica oil, Allium sativum powder and oleoresin of Zingiber officinale rhizome and their active molluscicidal components azadirachtin, allicin and 6]‐gingerol, alone or in combination (1 + 5) with PB or ENT 8184, caused a significant reduction in the activity of acetylcholinesterase, lactic dehydrogenase, acid and alkaline phosphatases and sodium‐potassium ATPase. There was a significant increase in the activity of succinic dehydrogenase. In vivo exposure for 24 h to sub‐lethal concentrations of azadirachtin, allicin and 6]‐gingerol, singly and with PB or ENT 8184, significantly altered the dopamine and 5‐hydroxytryptamine levels in the nervous tissue of L acuminata. It is concluded that these active moieties singly or with PB or ENT 8184 adversely affect all known neurotransmission mechanisms in the snail, either separately or through a complex interaction between the different neurotransmitters. © 2000 Society of Chemical Industry |
