Nicotine distribution nicotinic cholinergic brain receptors

Segal M, Dudai Y, Amsterdam A. (1978). Distribution of an alpha-bungarotoxin-binding cholinergic nicotinic receptor in rat brain. Brain Res. 148(1) 105-19. 

Figure 2.15. Distribution of muscarinic and nicotinic receptors in the human brain. Note the very restricted distribution of the nicotinic receptors. Cholinergic tracts arising from the magnocellular cholinergic nuclei innervate large areas of the cortex...

The cholinergic system in insects is the main target of insecticides. One class of molecules, the neonicotinoids, induces direct activation of the neuronal nicotinic acetylcholine receptors (nAChRs). In the honey bee these receptors are mainly distributed in the olfactory pathways that link sensory neurons to antennal lobes and mushroom bodies. These structures seem to play an important role in olfactory conditioning. We have previously shown that cholinergic antagonists injected in different parts of the brain impaired the formation and retrieval of olfactory memory. We then advanced the hypothesis that, through the activation of the nAChR, the neonicotinoid imidacloprid (IMI) would lead to facilitation of the memory trace. 

---