title: A pyrene fluorescence technique and microchamber for measurement of oxygen consumption of single isolated axons.
abstract: Pyrene fluorescence is quenched by oxygen in an inverse and linear manner related to the partial pressure of O2 in solution. We have developed a microchamber for measuring QO2 of a single isolated axon, monitoring the change in fluorescence of a pyrene probe. The probe consists of a Spectra/Por dialysis hollow fiber filled with 2.5 mM pyrene in paraffin oil. The probe is inserted into a 1-mm-i.d. 2-cm-long quartz capillary tube with a freshly isolated crayfish medial giant axon. The capillary is mounted in an apparatus that forms an air- and water-tight seal except for a 0.2-mm-i.d. stainless steel tube at both ends permitting the exchange of solutions. An Olympus inverted microscope, equipped with epifluorescence optics and a 150-W xenon lamp, is used to view the preparation, generate the excitation light, and monitor the emitted fluorescence with a photomultiplier tube placed in the microscope TV port. A dichroic filter unit is utilized to select an excitation wavelength of 350 nm and collect emitted light above 420 nm. The signal is amplified with a Keithley 480 picoammeter and recorded on a strip chart. QO2 of isolated axons was 552 +/- 70 X 10(-6) mol O2/liter tissue X min. Following sequential treatment with 2 mM ouabain and 2 mM NaCN, QO2 decreased by 22 and 82%, respectively. These data are consistent with QO2 measurements of whole nerve cord made with a Clark electrode O2 monitor.(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Department of Physiology, School of Medicine, East Carolina University, Greenville, North Carolina 27858.
authors: P T
authors: PT
authors: Hargittai
authors: D D
authors: DD
authors: Ginty
authors: E M
authors: EM
authors: Lieberman
mesh_terms: D000818:Animals; D003400:Astacoidea / Q000378:metabolism; D001369:Axons / Q000378:metabolism*; D005453:Fluorescence; D010101:Oxygen Consumption; D011721:Pyrenes
chemical_list: D011721:Pyrenes; C030984:pyrene