title: Opioid effects on 45Ca2+ uptake and glutamate release in rat cerebral cortex in primary culture.
abstract: Primary cultures of rat cortex, conveniently prepared from newborn animals, were used to study opioid effects on 45Ca2+ uptake and glutamate release. 45Ca2+ uptake, induced by treatment with glutamate or NMDA, was largely blocked by the NMDA antagonist MK-801. K+ depolarization-induced 45Ca2+ uptake was also reduced by MK-801, indicating that the effect was mediated by glutamate release. Direct analysis verified that glutamate, and aspartate, were indeed released. Opioid peptides of the prodynorphin system were also released and these, or other peptides, were functionally active, because naloxone treatment increased glutamate release, as well as the 45Ca2+ uptake induced by depolarization. Opioid agonists, selective for mu-, kappa-, and delta-receptors, inhibited the 45Ca2+ uptake induced by K+ depolarization. The combination of low concentrations of MK-801 and opioid agonists resulted in additive inhibition of K(+)-induced 45Ca2+ uptake. The results indicate that this system may be useful as an in vitro CNS model for studying modulation by opioids of glutamate release and Ca2+ uptake under acute, and perhaps also chronic, opiate treatment.
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Vlaskovska
authors.forename: M
authors.initials: M
authors.lastname: Schramm
authors.forename: I
authors.initials: I
authors.lastname: Nylander
authors.forename: L
authors.initials: L
authors.lastname: Kasakov
authors.forename: Z B
authors.initials: ZB
authors.lastname: You
authors.forename: M
authors.initials: M
authors.lastname: Herrera-Marschitz
authors.forename: L
authors.initials: L
authors.lastname: Terenius
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport / Q000187:drug effects; D002132:Calcium Radioisotopes / Q000493:pharmacokinetics; D002478:Cells, Cultured / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D002540:Cerebral Cortex / Q000166:cytology*; D004399:Dynorphins / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005260:Female; D005333:Fetus / Q000166:cytology; D018698:Glutamic Acid / Q000378:metabolism* / Q000494:pharmacology; D006706:Homeostasis / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D009020:Morphine / Q000494:pharmacology*; D016202:N-Methylaspartate / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009842:Oligopeptides / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000819:agonists
chemical_list: D000701:Analgesics, Opioid; D002132:Calcium Radioisotopes; D018690:Excitatory Amino Acid Agonists; D009292:Narcotic Antagonists; D009842:Oligopeptides; D011957:Receptors, Opioid; D009270:Naloxone; D018698:Glutamic Acid; D016202:N-Methylaspartate; D004399:Dynorphins; D009020:Morphine; D011188:Potassium