the god receptors
http://www.huffingtonpost.com/2008/07/21/study-the-effects-of-sero_n_114112.html

so it makes sense that tryptamines - close relatives of seratonin - should act as entheogens. this might also explain personal differences in reactions to similar doses of tryptamine compounds. and the genetic component in some traditions of shamanism. and probably a number of other remarkable phenomena.

According to Psychology Today and referencing the American Journal of Psychiatry, serotonin, the brain chemical in charge of moderating mood, metabolism, and sexuality, has been linked to spiritual experiences. Psychology Today reports:

A team of Swedish researchers has found that the presence of a receptor that regulates general serotonin activity in the brain correlates with people's capacity for transcendence, the ability to apprehend phenomena that cannot be explained objectively. Scientists have long suspected that serotonin influences spirituality because drugs known to alter serotonin such as LSD also induce mystical experiences. But now they have proof from brain scans linking the capacity for spirituality with a major biological element.

So what does this mean? Well, the researchers believe that it provides evidence that religiosity and spirituality are not defined necessarily or entirely by environmental or cultural factors, such as upbringing. Basically, those with a higher concentration of serotonin receptors will therefore most likely show a stronger inclination towards spiritual acceptance.