I was searching for similar compounds to nicotine since I'd like to take something similar without the health risks associated with it (which might just be more related to the delivery). I was searching for something that works primarily through the nicotinic acetylcholine receptor sites and found that Panax Ginseng has components which seem to increase activity through a somewhat similar manner (from what i'm gathering):
http://www.accessmyl...86-32097042_ITM
Cognitive Function Effects: The loss of nicotinic receptor binding has been associated with age-related cognitive impairments. Nicotinic receptor stimulation of the central nervous system is beneficial for neuroprotection against age-associated cognitive disorders. A non-ginsenoside component of the herb has demonstrated affinity for the nicotinic receptor. This binding of the compound to the receptor results in nicotinic activity (Lewis, 1999). Ginsenoside-Rg2 and--Rg3 block nicotinic acetylcholine and gamma-aminobutyric acid receptors. This results in an inhibitory effect of the acetylcholine-evoked secretion of catecholamines. (Tachikawa, 1999). These different effects of Panax ginseng contribute to the variety of pharmacological effects.
This would explain some of the effects of Ginseng.
Unrelated (but also interesting):
Also somewhat unrelated, if only with the common grounds of acetylcholine receptors, Ashwagandha seems to increase activity in muscarinic ACh receptors. It seems to be the anti-Piracetam, increasing focus but decreasing thought flow.