3: Long-term effects in monkeys
A very important experiment was performed in monkeys to determine if ecstasy can actually damage neurons. Monkeys were given ecstasy twice a day for four days (control monkeys were given saline). One group of monkeys' brains were removed two weeks later for analysis and another group of monkeys lived for an additional seven years before their brains were removed. Scientists examined the brains for the presence of serotonin. This image shows the presence of serotonin in neurons of the neocortex from three typical monkeys. On the left, the monkey who did not receive any ecstasy had a lot of serotonin (in pink) in the neocortex. Two weeks after a monkey received ecstasy, most of the serotonin was gone (point to the middle panel), suggesting that the serotonin neuron terminals were destroyed (there was no destruction of the serotonin cell bodies arising back in the brainstem). Point to the right-hand panel and show students that this damage appeared to be long-term because seven years later there was some recovery, but it was not complete. Scientists found similar changes in limbic areas of the brain such as the hippocampus and amygdala. The monkey experiments are an important reminder that humans may suffer the same fate, although this still remains to be demonstrated. Tell the students how difficult it is to do this same kind of experiment in humans, because it requires removing pieces of the brain to look for the loss of the serotonin neurons.
Explores the consequences of drug abuse on the brain and body and introduces the topics of prevention, and treatment.
As a result of scientific research, we know that addiction is a disease that affects both brain and behavior.