After nicotine is inhaled by smokers, it enters the pulmonary circulation from alveoli, enters the arterial circulation through the left ventricle and then enters the brain. Because nicotine has strong lipid affinity, it can accumulate in brain fat, but its action time is short, and it is absorbed by organs such as human lungs. Nicotine has effects on human peripheral nervous system and central nervous system. Because the autonomic nerve is stimulated, the number of heartbeats increases and blood pressure rises. The effect on the central nervous system, according to the state of people at that time, will play a corresponding role in mental excitement and sedation. Give a small amount of nicotine stimulation, and the cerebral cortex will be awake, excited and lonely. On the other hand, when the amount of nicotine absorbed by the human body reaches a certain level, it will lead to the decrease of the activity of the autonomic sympathetic nervous system, thus alleviating tension and anxiety. Nicotine contained in tobacco smoke has been proved to have a slight effect on mental excitement and sedation. In other words, when you are anxious or nervous, smoking can play a role in eliminating this emotion; When you are sleepy or slow-witted, smoking can clear your head. These two actions are called "two-stage actions". This effect of nicotine can be used to regulate mental state. In daily life, people also have the experience that smoking can eliminate stress and change their mood.
Of course, whether excitement is a pure physiological state may have different views from different angles. There are two ways to cause excitement: the excitement caused by mental factors, although its content will be evaluated differently because of different values, is basically "harmless" in physiology. The excitement caused by dependence on certain substances, such as cigarettes, alcohol and coffee, is "useless" in physiology, no matter what its purpose is. "Smoke and wine make poetry" is a phrase that everyone has heard. It is nothing more than saying that smoking and drinking have a refreshing effect and can help people create miracles. In fact, this is just a beautiful lie made up by smokers and alcoholics. However, you can see the heroic attitude of politicians and the elegance of writers in the smoke. Most writers like to create in quiet places. In the dead of night, flying in the ethereal realm of art, tobacco seems to be the most suitable. It is unreasonable to say that some ingredients in tobacco can inspire writers, but they can really achieve a sober and fulfilling psychological state in the smoke. Many of them don't pay attention to quitting smoking, and many of them quit smoking repeatedly. This is the most attractive group of smokers.
It is difficult to determine how much stimulation and excitement smoking has on people's nerves. When a person smokes a cigarette when his thoughts are stifled, his thoughts become like a flood. I'm afraid there are not many "obvious" examples. There is no evidence that the quality of thinking and writing has changed because of smoking. It seems that the role of tobacco is manifested through the accumulation of relatively small effects, which can be regarded as a hypothesis. But ... a person's psychological state is often "designed by himself", which is mentioned in many popular books. You think you are happy, and you will soon be really happy. Then, it can be said that tobacco makes you "think" your mental state completely new, increases your confidence in thinking and success, and really improves the efficiency of thinking. For a while, we were used to the idea that mental state was completely determined by external factors. The bias here lies in ignoring the adjustment of internal factors, which is exactly what the eastern traditional culture attaches importance to and emphasizes. When western modern medicine gradually understood the oriental method of paying equal attention to "form" and "spirit", the mental and psychological factors were re-evaluated. This is one of the most important reasons, if not the only reason, which can be used to explain that the mental and psychological effects of tobacco have been personally felt by hundreds of millions of people, although there is no empirical data.