title: Pressure antagonism of nitrous oxide depression of intracellular calcium in a neuroblastoma cell line.
abstract: While the ability of increased pressure to reverse anaesthesia has been well documented, the cellular or molecular mechanism(s) responsible for their mutual antagonism have remained elusive. Previous work in our laboratory, using diverse cell types, has indicated several processes requiring Ca2+ are affected in opposite directions by hydrostatic pressure [as represented by helium (He)], narcotic gases, and some anesthetics. Here we report on the effects of elevated pressures of He, and of 1 atm abs of the anesthetic gas nitrous oxide (N2O), when present alone and in combination, on calcium mobilization in the human neuroblastoma cell line SK-N-SH. Cytosolic-free Ca2+ ([Ca2+]i) was monitored by fluorescence spectrophotometry in cell suspensions loaded with the intracellular Ca2+ indicator fura-2. N2O reversibly depressed the carbachol-stimulated increase in [Ca2+]i (P < 0.01). The application of both 18 and 35 atm abs He attenuated this N2O-induced depression of carbachol-stimulated increase in [Ca2+]i. These findings support the hypothesis that pressure/anesthetic antagonism may be due in part to effects on neuronal [Ca2+]i and its regulation.
authors.affiliation: Department of Pharmacology and Toxicology, University of Western Ontario, London.
authors.forename: M C
authors.initials: MC
authors.lastname: Resendes
authors.forename: G
authors.initials: G
authors.lastname: Kalogeros
authors.forename: R B
authors.initials: RB
authors.lastname: Philp
mesh_terms: D018685:Anesthetics, Inhalation; D001274:Atmospheric Pressure; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D006371:Helium; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism; D009609:Nitrous Oxide; D011312:Pressure; D014407:Tumor Cells, Cultured
chemical_list: D018685:Anesthetics, Inhalation; D006371:Helium; D002217:Carbachol; D009609:Nitrous Oxide; D002118:Calcium