Presynaptic kainate receptor-mediated facilitation of glutamate release involves Ca2+–calmodulin and PKA in cerebrocortical synaptosomes

• Published in: FEBS letters 2013-03, Vol.587 (6), p.788-792
• Main Authors: Rodríguez-Moreno, Antonio, Sihra, Talvinder S.
• Format: Article
• Language: English
• Subjects: 8-Bromo Cyclic Adenosine Monophosphate - analogs & derivatives; 8-Bromo Cyclic Adenosine Monophosphate - pharmacology; Animals; Benzodiazepines - pharmacology; Ca2; Calcium - metabolism; Calmodulin; Calmodulin - metabolism; Cerebral Cortex - drug effects; Cerebral Cortex - metabolism; Cyclic AMP-Dependent Protein Kinases - antagonists & inhibitors; Cyclic AMP-Dependent Protein Kinases - metabolism; Excitatory Amino Acid Agonists - pharmacology; Excitatory Amino Acid Antagonists - pharmacology; Glutamate; Glutamic Acid - metabolism; Isoquinolines - pharmacology; Kainate receptor; Kainic Acid - pharmacology; Male; Presynaptic; Quinoxalines - pharmacology; Rats; Rats, Sprague-Dawley; Receptors, AMPA - antagonists & inhibitors; Receptors, AMPA - metabolism; Receptors, Kainic Acid - agonists; Receptors, Kainic Acid - antagonists & inhibitors; Receptors, Kainic Acid - metabolism; Receptors, Presynaptic - agonists; Receptors, Presynaptic - antagonists & inhibitors; Receptors, Presynaptic - metabolism; Sulfonamides - pharmacology; Synaptic Transmission - physiology; Synaptosome; Synaptosomes - drug effects; Synaptosomes - metabolism; Thionucleotides - pharmacology
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2013.01.071

► Kainate receptor activation mediates a facilitation of glutamate release in cerebrocortical synaptosomes. ► This facilitation of glutamate release involves the AC/cAMP/PKA pathway. ► AC is activated by Ca2+ from intraterminal stores. We have explored the mechanisms involved in the facilitation of glutamate release mediated by the activation of kainate receptors (KARs) in the cortex using isolated nerve terminals (synaptosomes). Kainate (KA) produced an increase on glutamate release at 100μM. The effect of KA was antagonized by NBQX (with AMPA receptors blocked by GYKI53655). This facilitation was suppressed by the inhibition of PKA activation by Rp-Br-cAMP and H-89. Moreover, the facilitation of glutamate release mediated by KAR requires the mobilization of intrasynaptosomal Ca2+ stores and the formation of a Ca2+–calmodulin complex. We conclude that KARs present on presynaptic terminals in the neocortex mediate the facilitation of glutamate release through a mechanism involving an increase in cytosolic Ca2+ to activate a Ca2+–calmodulin–AC/cAMP/PKA signaling cascade.