What are Sigma Receptors?
Sigma receptors (sigma is often written in Greek — σ — and if your web browser accepted that, you’re luckier than I am) are probably one of the most elusive entities in neuropharmacology. Our knowledge of sigma receptors pales in comparison to our ignorance; in fact, what we absolutely know (or at least think we absolutely know) can be summed up very briefly in the following paragraph: Scattered throughout the brain and body there are places (sigma binding sites) where a bunch of chemicals (sigma ligands) happen to stick. We don’t know if they’re on the outside or inside of cells. We don’t know if sticking a chemical to them does anything or not, except in the vas deferens. We don’t really know what they do, if they do anything. We don’t know what they’re for, why they’re there, or whether the body uses them. They may be neuroreceptors, steroid receptors, intracellular messenger receptors, growth regulators, enzymes, or something else entirely. In other words, prepare to be confused.
Discovered in 1976, sigma receptors (sigma is often written in Greek — σ — and if your web browser accepted that, you’re luckier than I am) are currently one of the most confusing entities in neuropharmacology. Our knowledge of sigma receptors pales in comparison to our ignorance; in fact, what we absolutely know (or at least think we absolutely know) can be summed up very briefly in the following paragraph: Scattered throughout the brain and body there are places (sigma binding sites) where a bunch of chemicals (sigma ligands) happen to stick. We don’t know if they’re on the outside or inside of cells. We don’t know if sticking a chemical to them does anything or not, except in the vas deferens. We don’t really know what they do, if they do anything. We don’t know what they’re for, why they’re there, or whether the body uses them. They may be neuroreceptors, steroid receptors, intracellular messenger receptors, growth regulators, enzymes, or something else entirely. In other words,
