I was reading into E-cigarettes and came across this article:

Nicotine is the major neuroactive compound of tobacco, which has, by itself, weak reinforcing properties. It is known that levels of the enzymes monoamine oxidase A (MAO-A) and MAO-B are reduced in the platelets and brains of smokers and that substances, other than nicotine, present in tobacco smoke have MAO-inhibitory activities. Here, we report that inhibition of MAO dramatically and specifically increases the motivation to self-administer nicotine in rats. These effects were more prominent in rats selected for high responsiveness to novelty than in rats with low responsiveness to novelty. The results suggest that the inhibition of MAO activity by compounds present in tobacco smoke may combine with nicotine to produce the intense reinforcing properties of cigarette smoking that lead to addiction.

Monoamine Oxidase Inhibition Dramatically Increases the Motivation to Self-Administer Nicotine in Rats -- Guillem et al. 25 (3: 8593 -- Journal of Neuroscience

Do you guys smoke (I do, myself), and if so what specifically does it do for you, what does it contribute to your inner life that keeps you doing it? What are your thoughts on smoking in conjunction with altered states?

I am fascinated by the idea of "rats selected for high responsiveness to novelty"

hmm, haven't heard that. well i don't smoke but it seems obvious that the reason why most people smoke cigarettes is because their heavily addicted one way or another

mapacho tobacco though does have a very long history of use in conjunction with ayahuasca. Not surprising since it does contain harmine, harmaline, and even THH if i recall correctly, and of course nicotine does have a few interesting affects on consciousness by itself

For myself this study holds no water what so ever. I used to smoke commercial cigarettes regularly and would even say that I was addicted at one point. There's something about commercial cigarettes, be it the additives or that it has a smaller amount of nicotine, that makes you crave another after another. Once I started smoking mapacho tho, which has significantly higher nicotine as well as mao-i, I stopped smoking as frequently. Now I only smoke a small bowl of mapacho maybe once or twice a week. So in effect the higher nicotine and mao-i helped me to cut down, which is the opposite of what this study reports.

For me nicotine helps with deep thinking for writing or praying etc and the mao-i is a nice natural mood stabilizer. I also always have mapacho around for tripping b/c it can calm me and re-center myself during a trip. It can also intensify the effects while giving you a greater sense of concentration which I always found to be enjoyable. In fact, shamans in the amazon blow it on people when they're going thru a difficult part of their ayahuasca journey.

One of my favorite spice experiences is a hand-rolled American Spirit cigarette with a little bit of spice sprinkled in there, or I rub the tobacco in some spice oil. It is a LOT more mellow than smoking straight spice, and is very relaxing on the body and mind. Little to no visuals at a low doses and vivid inwardly focused "energetic" visuals at higher doses. I have noticed smoking it this way causes me to salivate and therefore spit a lot, and the flavor and harshness of the cigarette gets pretty intense towards the end.

How does mapacho taste, and is it harsh to smoke?

It's hard to describe the taste, it's not really flavored just a more unique tobacco taste. I think it's called n. rustica for a reason, it has this earthy rustic tobacco taste to it not as crisp and distinct as n. tabacum. N. tabacum is the more popular commercial tobacco grown while mapacho (n. rustica) is used as insecticide for the garden or by tobacco shamans who are building a relationship with the plant and therefore need the stronger strand. N. rustica can contain around 9% nicotine where as n. tabacum contains around 3%.

Mapacho is definitely a harsher smoke but most people just rinse their mouth with it or cheek it instead of inhaling it. That way you're not bothering your throat and lungs.