title: [Mechanisms of morphine-evoked changes of intracellular calcium in primarily cultured hippocampal neurons].
abstract: OBJECTIVE
  In order to explore the neurobiological mechanism of morphine addiction and treatment methods, the acute and chronic effects of morphine on the intracellular free calcium concentration ([Ca2+]i) in cultured hippocampal neurons were investigated.
  
  
  METHODS
  Changes of [Ca2+]i induced by morphine in primarily cultured hippocampal neurons were measured by confocal laser scanning microscopy using Ca(2+) -sensitive dye fluo-4 as the calcium fluorescent probe.
  
  
  RESULTS
  Morphine actually induced the increase in [Ca2+]i of hippocampal neurons. This process could be blocked by naltrindole (delta opioid receptor antagonist) pretreatment, but not by CTOP (micro opioid receptor antagonist) pretreatment. Pretreatment of the cells with thapsigargin almost completely blocked morphine-evoked response; while pretreatment of the cells with verapamil partially inhibited this response. After exposure to 100 micromol/L morphine for 24 h, intracellular [Ca2+]i increased and the increase could be intensified after adding 10 micromol/L naloxone to the medium.
  
  
  CONCLUSIONS
  Morphine induced the release of Ca2+ is mainly from inositol 1, 4, 5-trisphosphate (IP3) sensitive stores in hippocampal neuron of rats through activation of delta2 subtype opioid receptor.
authors.affiliation: Department of Labour Hygiene, Third Military Medical University, Chongqing 400038, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.forename: Zheng-Ping
authors.initials: ZP
authors.lastname: Yu
authors.forename: Guang-Xu
authors.initials: GX
authors.lastname: Zhu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fang
authors.forename: Hai-Hong
authors.initials: HH
authors.lastname: Jiang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology*; D008297:Male; D018613:Microscopy, Confocal; D009020:Morphine / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009020:Morphine; D002118:Calcium