Effects of organophosphate pesticides on the olfactory organ of fish: a comprehensive review

Abstract

Olfaction results from stimulation of sensory receptor cells in the olfactory organs, which are innervated by the olfactory nerve (cranial nerve I) and transmit information to the brain. A paired olfactory organ in teleosts is located in the dorsal part of the snout in front of the eyes. Olfactory organ of teleost is composed of olfactory rosette (OR), olfactory bulb (OB) and olfactory nerve (ON). Pesticides such as Organophosphates are known to affect fundamental physiological systems (such as the enzyme acetylcholinesterase (AChE)), and have been shown to affect olfactory-mediated behaviours of fish. Organophosphate pesticides affected AChE activity levels in the OR and brain. organophosphate pesticide exposure significantly inhibited AChE activity in the OR, and both. These organophosphate pesticides affect the sensitivity of olfactory neurophysiology to pesticides acting not only potentially via AChE-inhibition, but also by other currently unknown modes of action.