Nicotine is a parasympathomimetic drug – weirdly enough the only other known substance in that category is muscarine, an active substance in Amanita muscura, or the Fly Ageric mushroom. The human body actually has receptors for that substance – why? At any rate another family member of nicotine is the nerve gas Serin.
Nicotine stimulates the Parasympathetic nervous system – this is not the autonomous nerve system gaba receptors work on, but rather the system responsible for stimulation of “rest-and-digest” or “feed and breed” activities that occur when the body is at rest, especially after eating, including sexual arousal, salivation, lacrimation (tears), urination, digestion and defecation. Its action is described as being complementary to that of the sympathetic nervous system, which is responsible for stimulating activities associated with the fight-or-flight response.
What does that mean? Well, it means every time you smoke a cigarette the PNS system is activated, which in humans is responsible for the fight or flight response – hence smoking actually causes enormous amounts of stress, while masquerading as something that brings quick relief. It is tied to the sexual circuit – one of the other reasons its hard to get rid of, as it is a more conscious form of the oral-suckling circuit gaba receptors as alcohol play on.
All these systematic drugs stem are very tightly connected to the era of industrialisation. If you want to reprogram monkeys to do the most insane sort of monotone activities you need substances that makes such insane monotony bearable. Hence, the cigaret, a little reward for the factory worker, the only joy in his life, and at night he returns home and can compensate his lack of real relationships with the other drug of choice, alcohol. Why are these the only legal drugs? Because they make monkeys into useful slaves. They play on the most primitive responses the human body is capable of.
All these sciences are still at their first baby steps. I don’t think we have any answers as to why the human body has muscarine receptors and how these could actually be used. Our principle task, as I see it, is to move humanity from the primitive drugs stage to one that actually involves the brain and the imagination.