In humans, levels of 5-HT 1A receptor activation in the brain show negative correlation with aggression,  and a mutation in the gene that codes for the 5-HT 2A receptor may double the risk of suicide for those with that genotype.  Serotonin in the brain is not usually degraded after use, but is collected by serotonergic neurons by serotonin transporters on their cell surfaces. Studies have revealed nearly 10% of total variance in anxiety-related personality depends on variations in the description of where, when and how many serotonin transporters the neurons should deploy. 
A traditional use of morning glory seeds by Mexican Native Americans was first described by Richard Schultes in 1941 in a short report documenting their use going back to Aztec times (cited in TiHKAL by Alexander Shulgin ). Further research was published in 1960, when Don Thomes MacDougall reported that the seeds of Ipomoea tricolor were used as sacraments by certain Zapotecs , sometimes in conjunction with the seeds of Rivea corymbosa , another species which has a similar chemical composition, with lysergol instead of ergometrine . Ergine was assayed for human activity by Albert Hofmann in self-trials in 1947, well before it was known to be a natural compound. Intramuscular administration of a 500 microgram dose led to a tired, dreamy state, with an inability to maintain clear thoughts. After a short period of sleep the effects were gone, and normal baseline was recovered within five hours.