title: Afobazole modulates microglial function via activation of both sigma-1 and sigma-2 receptors.
abstract: Microglial cells play a critical role in the neuroinflammatory response that accompanies various diseases of the central nervous system, such as ischemic stroke, and ATP is a major signaling molecule regulating the response of these cells to these pathophysiological conditions. Experiments were carried out to determine the effects of afobazole on microglial function and to identify the molecular mechanisms by which afobazole affects microglial cells. Afobazole was found to inhibit migration of microglial cells in response to ATP and UTP chemoattraction in a concentration-dependent manner. Inhibition of either σ-1 or σ-2 receptors decreased the effects of afobazole on microglia. In addition to inhibiting microglial cell migration, activation of σ receptors by afobazole decreased intracellular calcium elevation produced by focal application of ATP and UTP in isolated microglial cells. Furthermore, afobazole blocked membrane currents elicited by rapid application of ATP in microglial cells. Taken together, our data indicate that afobazole inhibits microglial response to P2Y and P2X purinergic receptor activation by functioning as a pan-selective σ-receptor agonist. In addition to modulating response to purinergic receptor activation, the effects of afobazole on microglial survival during in vitro ischemia were assessed. Application of afobazole during in vitro ischemia decreased microglial cell death during the ischemic episode and after a 24-h recovery period. Moreover, when afobazole was only applied after the ischemic episode, a significant enhancement in cell survival was still observed. Thus, afobazole acts via σ receptors to decrease microglial response to ATP and provides cytoprotection during and after ischemia.
authors.affiliation: Department of Molecular Pharmacology and Physiology, University of South Florida, College of Medicine, Tampa, Florida 33612-4799, USA. jcuevas@health.usf.edu
authors.forename: Javier
authors.initials: J
authors.lastname: Cuevas
authors.forename: Alex
authors.initials: A
authors.lastname: Rodriguez
authors.forename: Adam
authors.initials: A
authors.lastname: Behensky
authors.forename: Chris
authors.initials: C
authors.lastname: Katnik
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001562:Benzimidazoles / Q000494:pharmacology*; D002545:Brain Ischemia / Q000473:pathology; D002087:Butyrates / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D005029:Ethylenediamines / Q000494:pharmacology; D005260:Female; D008564:Membrane Potentials / Q000187:drug effects; D017628:Microglia / Q000187:drug effects*; D009025:Morpholines / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D010879:Piperazines / Q000494:pharmacology; D011247:Pregnancy; D058920:Purinergic P2X Receptor Antagonists / Q000494:pharmacology*; D058921:Purinergic P2Y Receptor Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017480:Receptors, sigma / Q000819:agonists*; D014326:Tropanes / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000096:biosynthesis; D000097605:Sigma-1 Receptor
chemical_list: D000255:Adenosine Triphosphate; D014151:Anti-Anxiety Agents; D001562:Benzimidazoles; D002087:Butyrates; D002118:Calcium; D005029:Ethylenediamines; D009025:Morpholines; D010879:Piperazines; D058920:Purinergic P2X Receptor Antagonists; D058921:Purinergic P2Y Receptor Antagonists; D017480:Receptors, sigma; D014326:Tropanes; D014544:Uridine Triphosphate; D000097605:Sigma-1 Receptor; C093337:1-(2-(3,4-dichlorophenyl)ethyl)-4-methylpiperazine; C410924:2-((2-morpholino)ethylthio)-5-ethoxybenzimidazole; C106107:sigma-2 receptor; C107044:SM 21; C097963:N-(2-(3,4-Dichlorphenyl)ethyl)-N,N',N'-trimethyl-1,2-ethandiamin