Prodynorphin
Prodynorphin is an opioid polypeptide or protein that is a basic building block of endorphins, the chemical messengers in the brain that appear most heavily involved in the anticipation and experience of pain (and possibly pleasure – the two pathways are closely interrelated chemically) as well as the formation of deep emotional bonds. Endorphins are also critical in learning and memory. Additionally, prodynorphin is a precursor to the neurotransmitters dynorphin A and dynorphin B, both additional opioids.
Prodynorphin levels also seem to be highly correlated with variations in human perception. Studies have shown a positive correlation between low levels of prodynorphin and susceptibility to cocaine addiction. Additional studies have revealed a significant link between certain variations in prodynorphin and the development of epilepsy and schizophrenia. It is likely, as more attention is paid to this previously obscure neural chemical, that more effects will be found.
Recently, interesting discoveries centered around prodynorphin have led researchers to wonder if it is may contribute to the distinctions between humans from other primates. Though all primates possess a nearly identical set of prodynorphin proteins, in humans a gene causes prodynorphins to produce more prolifically than they do in non-human primates. In addition, with 98-99% of genetic base material in humans and other primates being close to identical, the section related to prodynorphins differs by as much as 10%, and there are striking differences in the production of prodynorphins from one population of humans to the next.
Experimental introduction of human and chimpanzee prodynorphin gene segments into human neural cells saw a dramatic difference in prodynorphin expression; the human version expressed 20% more than the chimpanzee version.
Scientists hypothesize that the extra production of prodynorphin encouraged emotional bonding as well as the development of human intelligence and maybe even language. Many are speculating that prodynorphin may be one of the first genetic markers that truly demonstrates what makes us human.
Web Resources On Prodynorphin
Evolution of prodynorphin
Gene regulation changes had major impacts on human evolution
Book Resources On ProdynorphinEndorphins, Opiates, and Behavioural Processes by R. J. Rodgers
Opioids in Pain Control : Basic and Clinical Aspects by Christoph Stein
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