title: Cell-specific patterns of oscillating free Ca2+ in carbamylcholine-stimulated insulinoma cells.
abstract: The effect of the muscarinic agonist carbamylcholine on cytoplasmic Ca2+ concentration ([Ca2+]i was examined at the single cell level in clonal pancreatic beta-cells (HIT). Cells were loaded with the indicator dye fura 2, and [Ca2+]i was measured by microfluorimetry. Carbamylcholine induced changes in Ca2+ that differed from cell to cell and provoked in some cells oscillatory Ca2+ fluctuations. During a transient, free Ca2+ rose to a peak within 1-3 s. The frequency of the oscillations increased with agonist concentration. Oscillations in [Ca2+]i occurred in the absence of external Ca2+. When cells were perifused for a sufficient period of time without carbamylcholine, near identical Ca2+ responses were elicited in each cell by successive applications of the agonist. Thus, individual cells displayed characteristic and reproducible Ca2+ responses with respect to amplitude, frequency, and shape of the transients as well as latency in onset of the initial Ca2+ rise. We propose that the biological response to a Ca2+ agonist in a given cell is not only determined by the frequency and amplitude of Ca2+ oscillations but is governed by the unique pattern of the Ca2+ signal of each cell, which may be termed "Ca2+ fingerprint."
authors.affiliation: Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104.
authors.forename: M
authors.initials: M
authors.lastname: Prentki
authors.forename: M C
authors.initials: MC
authors.lastname: Glennon
authors.forename: A P
authors.initials: AP
authors.lastname: Thomas
authors.forename: R L
authors.initials: RL
authors.lastname: Morris
authors.forename: F M
authors.initials: FM
authors.lastname: Matschinsky
authors.forename: B E
authors.initials: BE
authors.lastname: Corkey
mesh_terms: D007516:Adenoma, Islet Cell / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology*; D002460:Cell Line; D003600:Cytosol / Q000378:metabolism; D005470:Fluorometry; D006706:Homeostasis; D007340:Insulinoma / Q000378:metabolism*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000378:metabolism*
chemical_list: D002217:Carbachol; D002118:Calcium