Sigma receptor is a non-opioid receptor that binds diverse classes of psychotropic drugs. Sigma receptors are subdivided into two subtypes, sigma-1 and sigma-2. The sigma-1 receptor (σ1R) is a chaperone protein at the endoplasmic reticulum (ER) that modulates calcium signaling through the IP3 receptor. The sigma-2 receptor (σ2R) has been found highly expressed in malignant cancer cells, and is currently under investigation for its potential diagnostic and therapeutic uses.
An overview of sigma receptor
Sigma receptor is a non-opioid receptor that binds diverse classes of psychotropic drugs. The receptor is mainly distributed in the emotional regulation region and the brainstem movement area, and the content is also high in the substantia nigra, caudate nucleus, epencephalon, locus ruber, hippocampus, amygdaloid body and cingulate gyrus equilateral system, closely related to the study and memory, psychotic symptoms, psychological craving and drug seeking behavior. For example, σreceptors in the brain's gray matter in the concentration of higher than white, at the same time, in the region rich in large nerve cell receptor concentration is high, such as the Purkinje of the cerebellum, the cone-like cell layer and red nucleus of the hippocampus.
Major types of sigma receptor
Sigma receptors are subdivided into two subtypes, sigma-1 (σ-1) receptor and sigma-2 (σ-2) receptor.
Inhibition of sigma receptor
S1RA is an effective selective antagonist of σ-1 receptor and the first σ-1 receptor antagonist, showing effective analgesic activity in various pain models. Ligand receptor binding experiments showed that S1RA had a good affinity for σ-1 receptor antagonists infected with HEK293 cell membranes. In mice experiments, S1RA had a strong analgesic effect on capsaicin-induced mechanical pain hypersensitivity and formalin pain. In addition, S1RA can inhibit mechanical pain hypersensitivity and thermal hypersensitivity in the model of partial sciatic nerve ligation in mice.
Sigma receptor and diseases
Schizophrenia is an unknown cause of severe psychosis, and the general view is that it has a high degree of relevance with the genetic variation. Interestingly, genome wide association study (GWAS) found that there was a significant expression of σ-2 gene in schizophrenic patients, so the σ-2 receptor may be associated with the onset of schizophrenia. At the same time, some scholars believe that the σ-2 receptor may also be involved in the treatment of schizophrenia.