title: In vivo study of ethanol-activated brain protein kinase A: manipulations of Ca2+ distribution and flux.
abstract: BACKGROUND
  The cAMP-dependent protein kinase (PKA) signaling transduction pathway has been shown to play an important role in the modulation of several ethanol (EtOH)-induced behavioral actions. In vivo, short-term exposure to EtOH up-regulates the cAMP-signaling cascade. Interestingly, different Ca(2+) -dependent cAMP-PKA cascade mediators play a critical role in the neurobehavioral response to EtOH, being of special relevance to the Ca(2+) -dependent adenylyl cyclases 1 and 8. We hypothesize an intracellular PKA activation elicited by EtOH administration, which may be regulated by a Ca(2+) -dependent mechanism as an early cellular response. Thus, the present work aims to explore the role of Ca(2+) (internal and external) on the EtOH-activated PKA cascade.
  
  
  METHODS
  Swiss male mice received an intraperitoneal injection of EtOH (0 or 4 g/kg), and brains were dissected following a temporal pattern (7, 15, 30, 45, 90, or 120 minutes). Either the enzymatic PKA activity or its fingerprint was analyzed on different brain areas (cortex, hypothalamus, hippocampus, and striatum). To explore the role of Ca(2+) on the EtOH-activated PKA cascade, mice were pretreated with diltiazem (0 or 20 mg/kg), dantrolene (0 or 5 mg/kg), or 3,7-Dimethyl-1-(2-propynyl)xanthine (0 or 1 mg/kg) 30 minutes before EtOH (4 g/kg) administration. After 45 minutes of EtOH administration, brains were removed and dissected to measure the PKA activity or its fingerprint.
  
  
  RESULTS
  Results from these experiments showed an EtOH-dependent activation of PKA in different brain areas. Manipulations involving a disruption of intracellular Ca(2+) release from the endoplasmic reticulum resulted in a decreased EtOH-induced activation of PKA. On the contrary, extracellular-to-cytoplasm Ca(2+) manipulations did not prevent the PKA activation by EtOH.
  
  
  CONCLUSIONS
  Altogether, these results show the critical role of stored Ca(2+) as an intracellular mediator of different neurobiological actions of EtOH and provide further evidence of a possible new target for EtOH within the central nervous system.
authors.affiliation: Area de Psicobiologia, Universitat Jaume I, Castellón, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Baliño
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Ledesma
authors.forename: Carlos M G
authors.initials: CM
authors.lastname: Aragon
mesh_terms: D058917:Adenosine A2 Receptor Antagonists; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D051379:Mice; D013805:Theobromine / Q000031:analogs & derivatives
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D002121:Calcium Channel Blockers; D002492:Central Nervous System Depressants; D000431:Ethanol; C057837:3,7-dimethyl-1-propargylxanthine; D017868:Cyclic AMP-Dependent Protein Kinases; D013805:Theobromine; D002118:Calcium
keywords: Adenylyl Cyclase; Alcohol Addiction; Ca2+; Ion Channels; Protein Kinase A; Ryanodine Receptor