Prodynorphin, also known as proenkephalin B, is an
opioid
Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...
polypeptide hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are require ...
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
endorphin
Endorphins (contracted from endogenous morphine) are chemical signals in the brain that block the perception of pain and increase feelings of wellbeing. They are produced and stored in an area of the brain known as the pituitary gland.
Hist ...
s, 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.
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
primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...
s have only a single copy. In addition, most
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
n populations have two copies of the gene sequence for prodynorphin, whereas
East Africas,
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
erners, and
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
ans tend to have three repetitions.
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
Indiana University (IU) is a system of public universities in the U.S. state of Indiana.
Campuses
Indiana University has two core campuses, five regional campuses, and two regional centers under the administration of IUPUI.
*Indiana Universi ...
, "this is the first documented instance of a neural gene that has had its regulation shaped by natural selection during
human origins."
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.
See also
*
Dynorphin
Dynorphins (Dyn) are a class of opioid peptides that arise from the precursor protein prodynorphin. When prodynorphin is cleaved during processing by proprotein convertase 2 (PC2), multiple active peptides are released: dynorphin A, dynorphin ...
*
Proenkephalin
Introduction
Proenkephalin (PENK), formerly known as proenkephalin A (since proenkephalin B was renamed prodynorphin), is an endogenous opioid polypeptide hormone which, via proteolyic cleavage, produces the enkephalin peptides etnkephal ...
*
Proopiomelanocortin
Pro-opiomelanocortin (POMC) is a precursor polypeptide with 241 amino acid residues. POMC is synthesized in corticotrophs of the anterior pituitary from the 267-amino-acid-long polypeptide precursor pre-pro-opiomelanocortin (pre-POMC), by the ...
(POMC)
References
External links
Scienceagogo.com- 'Drug Gene Link To Human Evolution' (November 15, 2005)
{{Opioidergics
Neuropeptides
Opioid peptides
Signal transduction
Precursor proteins