1R

1R may refer to:

See also

Sigma-1 receptor

The sigma-1 receptor (σ₁R), one of two sigma receptor subtypes, is a chaperone protein at the endoplasmic reticulum (ER) that modulates calcium signaling through the IP3 receptor. In humans, the σ₁ receptor is encoded by the SIGMAR1 gene.

The σ₁ receptor is a transmembrane protein expressed in many different tissue types. It is particularly concentrated in certain regions of the central nervous system. It has been implicated in myriad phenomena, including cardiovascular function, schizophrenia, clinical depression, the effects of cocaine abuse, and cancer. Much is known about the binding affinity of hundreds of synthetic compounds to the σ₁ receptor.

An endogenous ligand for the σ₁ receptor has yet to be conclusively identified, but tryptaminergic trace amines, as well as neuroactive steroids such as dehydroepiandrosterone (DHEA) and pregnenolone all activate the receptor.

Characteristics

The σ₁ receptor is defined by its unique pharmacological profile. In 1976 Martin reported that the effects of N-allylnormetazocine (SKF-10,047) could not be due to activity at the μ and κ receptors (named from the first letter of their selective ligands morphine and ketazocine, respectively) and a new type of opioid receptor was proposed; σ (from the first letter of SKF-10,047). However, ligands acting at this new “opioid” receptor were not blocked by the classical opioid antagonists naloxone and naltrexone. Consequently, the opioid classification was eventually dropped and the receptor was later termed the σ₁ receptor. It was found to have affinity for the (+)-stereoisomers of several benzomorphans (e.g., (+)-pentazocine and (+)-cyclazocine), various structurally and pharmacologically distinct psychoactive chemicals such as haloperidol and cocaine, and neuroactive steroids like progesterone.