Endorphins, whose name is derived from the Greek words endogenous and morphine, are opioid peptide neurotransmitters. Opioid neurotransmitters work by binding to the receptors in the central nervous system. These neurotransmitters are called opioid receptors because they react with the same nervous system receptors as any drug of the opiate class. Some of the activities that can cause production of endorphins are consumption of spicy food, orgasm, love, pain, and excitement. Endorphins have the same effects on perception similar to that of using opiate drugs, those being a sense of well-being, calmness, and confidence. The word endorphin is intended to mean morphine like substances that are naturally produced by the body. Endorphins are useful when injured because the sense of confidence and well-being can stop the injured from panicking and losing control, helping them stay coherent and active for a longer period of time.
Endorphins were originally discovered by two groups of researchers in the year of 1974. Hans Kosterlitz and John Hughes isolated endorphins in a pig brain, originally calling them enkephalins, in reference to the cerebrum. During the same year a second group of researchers, Solomon Snyder and Rabi Simantov from the US discovered the naturally produced opioid peptides in the brain of a calf and were the first to name them endorphins.
Endorphins can be produced and released by both the brain and the pituitary gland. The brain releases the substances into the spinal cord and the pituitary gland releases them into the blood. It is believed that endorphins are produced by the hypothalamic gland in the brain, the hypothalamic neurons is thought to release the substance into the rest of the brain and the spinal fluid. Endorphins inhibit the release of the neurotransmitter that cause excitement (GABA) and can increase the production of dopamine by the same neurotransmitters. This explains why the main effects of endorphins are to calm the subject and to produce a sense of well-being. The neurotransmitter Dopamine is directly related to problems with depression/mania with insufficient levels of dopamine causing a state of depression. Higher levels of Dopamine can cause a state of increased activity, explaining why people with endorphins being released into the brain and blood continue remain active.
One of the most well-known effects of endorphins is the increased state of awareness called “runners high”. This occurs when prolonged strenuous exercise is performed by a person or animal. When aerobic activity is prolonged and breathing is difficult endorphins will be released. The downside of this effect is that the exercise may be too strenuous for the body to safely maintain the activity level and damage can possibly be done to the muscle or soft tissue without the subject realizing they have been injured.
Wikipedia. (2011). Retrieved from http://en.wikipedia.org/wiki/Endorphins
Medicine.net. (2011). Retrieved from http://www.medicinenet.com/script/main/art.asp?articlekey=55001