RVD-Hpα

RVD-Hpα (pepcan-12) is an

endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...

neuropeptide Neuropeptides are chemical messengers made up of small chains of amino acids that are synthesized and released by neurons. Neuropeptides typically bind to G protein-coupled receptors (GPCRs) to modulate neural activity and other tissues like the ...

found in human and mammalian brain, which was originally proposed to act as a selective

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

for the CB₁

cannabinoid receptor Cannabinoid receptors, located throughout the body, are part of the endocannabinoid system of vertebrates a class of cell membrane receptors in the G protein-coupled receptor superfamily. As is typical of G protein-coupled receptors, the cann ...

. It is a 12-amino acid

polypeptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty ...

having the amino acid sequence Arg-Val-Asp-Pro-Val-Asn-Phe-Lys-Leu-Leu-Ser-His and is an

N-terminal The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amin ...

extended form of

hemopressin Hemopressin (Hp) is an alpha hemoglobin fragment with the sequence PVNFKFLSH, originally identified in extracts of rat brain using an enzyme capture technique. It binds cannabinoid receptors, acting as an inverse agonist at CB1 receptors. Longer ...

, a 9-AA polypeptide derived from the α₁ subunit of

hemoglobin Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin ...

which has previously been shown to act as a CB₁ inverse agonist. All three polypeptides have been isolated from various mammalian species, with RVD-Hpα being one of the more abundant neuropeptides expressed in

mouse brain A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus'' ...

, and these neuropeptides represent a new avenue for cannabinoid research distinct from the previously known endogenous

lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...

-derived cannabinoid agonists such as

anandamide Anandamide (ANA), also referred to as ''N''-arachidonoylethanolamine (AEA) is a fatty acid neurotransmitter belonging to the fatty acid derivative group known as N-acylethanolamine (NAE). Anandamide takes its name from the Sanskrit word ''ananda ...

. Recently it was shown that RVD-Hpα (also called Pepcan-12) is a potent negative allosteric modulator at CB₁ receptors, together with other newly described N-terminally extended peptides (pepcans). Pepcan-12 is the major peptide of a family of endogenous peptide

endocannabinoids Cannabinoids () are several structural classes of compounds found primarily in the ''Cannabis'' plant or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tetrahydrocannabinol (THC) (delta-9-THC), the primary psychoact ...

(pepcans) shown to act as negative allosteric modulators (NAM) of cannabinoid CB1 receptors. It is shown that pepcan-12 opposite acts as a potent CB2 cannabinoid receptor positive allosteric modulator (PAM). This peptide is very specifically expressed in the noradrenergic neurons in the brain, mainly the locus coeruleus and its projections and in the adrenal medulla. RVD-Hpα also significantly potentiated the effects of CB2

receptor agonists An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the agoni ...

, including the endocannabinoid

2-arachidonoyl glycerol 2-Arachidonoylglycerol (2-AG) is an endocannabinoid, an endogenous agonist of the CB1 receptor and the primary endogenous ligand for the CB2 receptor. It is an ester formed from the omega-6 fatty acid arachidonic acid and glycerol. It is presen ...

(2-AG), for GTPγS binding and

cAMP Camp may refer to: Areas of confinement, imprisonment, or for execution * Concentration camp, an internment camp for political prisoners or politically targeted demographics, such as members of national or minority ethnic groups * Extermination ...

inhibition (5–10 fold). The

putative {{Short pages monitor