In this transcript of a 1993 interview between Bill Moyers and Candace Pert, Dr. Pert does a wonderful job of explaining that very perplexing subject: how can chemicals produced by the body make us feel emotions?
Pert was the scientist who discovered the receptors for endorphins, the body's natural opiates. She discovered, moreover, that endorphins and other so-called neurochemicals are produced and taken up not only in the brain, but in many other parts of the body. She wrote about her research, which led her toward examinations of consciousness, soul and the mind/body connection, in her book "The Molecules of Emotion."
Pert says a good way to think of neuropeptides and their receptors is to think of the receptors as satellite dishes that receive chemical communications and respond to them in ways specific to their place in the body. For example, the peptide angiotensin "tells" the kidneys and lungs to conserve water, while it makes the brain feel thirsty, so the body will drink more water.
Moyers: So you’re saying that my emotions are the same as my physical reactions, and that they occur when a particular molecule hits a particular receptor?
Pert: I believe that’s true, yes.
Moyers: You’ve seen the molecule hit a receptor?
Pert: Absolutely. I’ve measured it.
Moyers: But have you seen the emotion it carries with it?
Pert: I’ve seen animals behave as if they had that emotion. Scientists who study rat and monkey behavior have seen animals behaving and have measured increases and decreases in the amounts of the neuropeptides being released.
Moyers: You know from scientific research that certain reactions occur when the neuropeptide hits the receptor. But there isn’t any way to identify the emotion that emerges from that, is there?
Pert: We’re really in the very early stages of being able to figure out which peptide mediates which emotion or whether combinations of peptides are involved. We have a few that we know pretty well because we have psychoactive drugs that give a certain effect. For example, we know that cocaine is a euphoriant, and we know what receptor system it interacts with in the brain.
Since this interview, functional MRIs have al.owed scientists to watch various parts of the brain as they're activated by external stimuli and exogenous peptides, including oxytocin.
We still don't totally understand just how a peptide like oxytocin translates into the experience of emotion, but we're much closer.