Nicotinic acetylcholine receptors organophosphate binding

Nicotine binds to a type of receptor, now called a nicotinic receptor, and causes the same effects as a release of the neurotransmitter acetylcholine at nerve endings. In this it is similar to organophosphates, which lead to excess acetylcholine at nerve endings (see pp. loo-ioi). Nicotine first excites and then inhibits the central nervous system it first stimulates and then paralyses nerves. It reacts with receptors in muscle and nerves, and is able to enter the brain from the bloodstream and interact with nicotinic receptors. At first there is a stimulation, with the smoker experiencing alertness and decreased irritability, aggression, and anxiety. With higher doses there is depression of the brain as a result of saturation of the receptors. 

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