Prodynorphin

Prodynorphin, also known as proenkephalin B, is an opioid polypeptide hormone involved with chemical signal transduction and cell communication. The gene for prodynorphin is expressed in the endometrium and the striatum, and its gene map locus is 20pter-p12. Prodynorphin 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 the formation of deep emotional bonds, and that are also critical in learning and memory.^[1]^[2]

The gene is thought to influence perception, as well as susceptibility to drug dependence, and is expressed more readily in human beings than in other primates.

Evolutionary implications

Most humans have multiple copies of the regulatory gene sequence for prodynorphin, which is virtually identical among all primates, whereas other primates have only a single copy. In addition, most Asian populations have two copies of the gene sequence for prodynorphin, whereas East Africas, Middle Easterners, and Europeans tend to have three repetitions.^[3]

The extent of regulatory gene disparities for prodynorphin, between human and primates, has gained the attention of scientists. There are very few genes known to be directly related to mankind's speciation from other great apes. According to computational biologist researcher Matthew W. Hahn of Indiana University, "this is the first documented instance of a neural gene that has had its regulation shaped by natural selection during human origins."^{[citation needed]}

The prodynorphin polypeptide is identical in humans and chimpanzees, but the regulatory promoter sequences have been shown to exhibit marked differences. According to Hahn, "humans have the ability to turn on this gene more easily and more intensely than other primates", a reason why regulation of this gene may have been important in the evolution of modern humans' mental capacity.^{[citation needed]}

References

^ Charles Chavkin; William J Shoemaker; Jacquiline F. McGinti; Alejandro Bayon; Floyd E. Bloom (March 1985). "Characterization of the Prodynorphin and Proenkephalin Neuropeptide Systems in Rat Hippocampus" (PDF). Journal of Neuroscience. 5 (3): 806–816. doi:10.1523/jneurosci.05-03-00808.1985. PMC 6565022. PMID 3838345.
^ Alberto Pérez-Rosado; María Gómez; Jorge Manzanares; José A. Ramos; Javier Fernándezruiz (2002). "Changes in prodynorphin and POMC gene expression in several brain regions of rat fetuses prenatally exposed to Δ-tetrahydrocannabinol". Neurotoxicity Research. 4 (3): 211–218. doi:10.1080/10298420290023936. PMID 12829401. S2CID 25878244.
^ Chang-wang Wang; Min Ma; Wei-guang Lu; Ru-qin Luo (11 September 2019). "Association between prodynorphin gene polymorphisms and opioid dependence susceptibility: a meta-analysis". BMC Psychiatry. 19 (281): 281. doi:10.1186/s12888-019-2272-7. PMC 6737717. PMID 31510971. S2CID 202550535.