A Perspective on sigma-1 receptor research: Past and future

The description of the sigma-1 receptor came about as a binding site for a subtype of opioid receptors which was soon rectified as a non-opioid receptor of its own. It has been 33 years after the first description of the sigma-1 receptor during which period the receptor has been demonstrated to be a protein with many never-before described features. The reason for this uniqueness of the sigma-1 receptor is partly due to the fact that its sequence does not resemble that of any mammalian proteins, leading to the situation that no pre-existing description could be followed in searching for its potential physiological roles. It is also because of this uniqueness of the sigma-1 receptor that opens up opportunities to search for its functions in many physiological systems particularly as they may relate to human diseases. It is thus a great pleasure to see that the Journal of Pharmacological Sciences is devoting a special issue in the beginning of year 2015 to focus on the sigma-1 receptor research.