The results of this study indicate that MK801 directly inhibits the Kv channel in a state-independent manner in RMASMCs. This MK801 inhibition of Kv channels, in addition to the NMDAr block, should be considered when assessing

the various pharmacological effects of MK801 such as schizophrenia, neuroprotection, and hypertension. All authors declare that there is no conflict of interest. This research was supported by Konkuk University. “
“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 find more 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. The sigma-1 receptor has SCR7 in vitro so far been implicated in diseases including Alzheimer’s disease, Parkinson’s disease, psycho-stimulant addiction, cancer, myocardial hypertension, aging, cognition, depression,

fronto-temporal lobar motor Parvulin neuron degeneration, amyotrophic lateral sclerosis, and HIV-associated neural dementia. As sigma-1 receptors exist in immune systems, functions of sigma-1 receptors in certain immune system have also been reported in the literature. This plethora of involvement of sigma-1 receptors in so many different types of diseases raises a fundamental question: what is the mode of action of the sigma-1 receptor that relates this receptor to so many different diseases? This has been a “burning” question for many researchers both inside and outside of the field of the sigma-1 receptor. The discovery that the sigma-1 receptor is an endoplasmic reticulum (ER) chaperone that resides mainly in the interface between the ER and mitochondrion, referred to as the MAM (mitochondrion-associated ER membrane), has provided a piece of pivotal information to understanding the receptor’s function. Further, the demonstration that sigma-1 receptors can translocate to other areas of cells or neurons, when stimulated by its agonists such as neurosteroids or psychostimulants, adds additional dimensions to understanding the receptor’s mode of action and associated physiological functions.