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Chloride transport in cystic fibrosis fibroblasts
Abstracts EF 24 OXYGEN UPTAKEOF ISOLATEDTOADSKIN EPITHELIUM: MICROMKASUREMENT ANDCONTRIBUTION OF MITOCHONDRIA-RICH CELLS. E. Raddatz, (l), U. Katz (2) and P. Kucera (l), (1) Inst. of Pz; siology, Univ. of Lausanne, Switzerland, Dept. of Biology, Technion, Haifa, Israel.
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EF 25 CHLORIDE TRANSPORT IN CYSTIC FIBROSIS FIBROBLASTS. M. Rugolo, T. Mastrocola and G. Lenaz, Dipart. Biologia Ev. Sp., 1st. Botanico, 42 Irnerio 40126 Bologna-I.
A defect in Cl- transport across epithelial cells is involved in cystic fibrosis (CF). In The 0 uptake of the isolated toad skin epithis study membrane permeability to Cl has theli&n (Bufo viridis) was measured in vitro been measured in skin fibroblasts3Qrog normal by the spectrophotometric oxyhemoglobin me- and CF individuals by following Cl efflux thod . Mitochondria-rich cells (MRC) density under steady-state conditions. Cl- efflux increased in skins of toads preacclimated in from fibroblasts involved two intracellular chloride-free solution (NaNO3) as compared to compartments characterized by slow- and fastthe density in skins of NaCl-acclimated rate constants of efflux. The former, which toads. uptake of MRCrich epithelia The 0 is linked to transport across the plasmamen+ (NaNO3-acclimaged) was significantly higher brane, was strongly reduced in CF fibroblasts than that from NaCl-acclimated to2ds (i.e. in comparison with controls. Furthermore, Cl 0.88 + 0.44 and 0.63 + 0.37 nmolm ah, re- efflux was slightly enhanced by preincubation spectively). These results suggest that under with the beta-agonist epinephrine or with the the acclimation conditions where sodium cell permeant 8-bromo-cAMP. However, no diftransport across the skin is greatly sup- ference was observed between normal and CF pressed the O2 uptake of the epithelium is cells in the response to both compounds. linked to the density of MFX. (Supported by Prog. Finaliz.: Ingegneria Genetica e Basi Molecolari delle Malattie Ereditarie, C.N.R. Rome).
EF 27 EF 26 DEGENERATIVE CHANGES IN THE SENSORY EPITHELIALKALINIZATION INDUCED HYPERPOLARIZATION P. Teunis, MEMBRANE POTENTIAL UM OF CATFISH ELECIRORECEPTORS. (DHIH) OF THE PERITUBULAR The (V ) of NECTURUS PROXIMAL TUBULE IS REDUCEDLab. Comp. Physiology, Univ. of Utrecht, Netherlands. IN1 THE ABSENCE OF SUBSTRATES.P.S. Steels, and M. Granitzer, LUC, Univ. campus, B-3610 The electroreceptive cells of a small pit Dipenbeek, Belgie. organ in the freshwater catfish Ictalurus nebulosus LeS. all project onto one afferent Necturus kidneys were artificially perfused nerve fiber. We have studied the consequences with HCOZ-free Hepes buffered salt solution sencontainin the following substrates in mM: of denervation on: spontaneous activity, sitivity to sinusoidal stimuli and latency of 3.6 lactate, 3 butyric acid, 2.22 alucose. 0.5 alanine, 6.5 glutamine, 0.2 lysine and the pulse reponse. Within 6 to 8 hrs following denervation the spontaneous frequency 0.05 glutaminic acid. Acute peritubular withwhile the sensitivity drawal of all substrates except glucose at pH decreases dramatically, as the latency to a pulse stimulus 7.5 induced a depolarization of V of +18 mv. as well Sudden peritubular addition of th& same sub- remain largely unchanged. This points to the existence of two separate mechanisms for the to kidneys perfused with glucose strates and the modulaalone hyperpolarized Vl, with -6 mv. pHIH due generation of the spike-train of this activity. Within 24 to 36 hrs. to a short-term change in peritubular pH from tion activity has ceased. 7.5 to 8.5 was 55% reduced in the absence of after denervation all The results are analyzed in terms of a stothe above mentioned substrates except gluchastical model with emphasis on the change case . in synaptic events taking place in the time course of degeneration.
835
EF 25 CHLORIDE TRANSPORT IN CYSTIC FIBROSIS FIBROBLASTS. M. Rugolo, T. Mastrocola and G. Lenaz, Dipart. Biologia Ev. Sp., 1st. Botanico, 42 Irnerio 40126 Bologna-I.
A defect in Cl- transport across epithelial cells is involved in cystic fibrosis (CF). In The 0 uptake of the isolated toad skin epithis study membrane permeability to Cl has theli&n (Bufo viridis) was measured in vitro been measured in skin fibroblasts3Qrog normal by the spectrophotometric oxyhemoglobin me- and CF individuals by following Cl efflux thod . Mitochondria-rich cells (MRC) density under steady-state conditions. Cl- efflux increased in skins of toads preacclimated in from fibroblasts involved two intracellular chloride-free solution (NaNO3) as compared to compartments characterized by slow- and fastthe density in skins of NaCl-acclimated rate constants of efflux. The former, which toads. uptake of MRCrich epithelia The 0 is linked to transport across the plasmamen+ (NaNO3-acclimaged) was significantly higher brane, was strongly reduced in CF fibroblasts than that from NaCl-acclimated to2ds (i.e. in comparison with controls. Furthermore, Cl 0.88 + 0.44 and 0.63 + 0.37 nmolm ah, re- efflux was slightly enhanced by preincubation spectively). These results suggest that under with the beta-agonist epinephrine or with the the acclimation conditions where sodium cell permeant 8-bromo-cAMP. However, no diftransport across the skin is greatly sup- ference was observed between normal and CF pressed the O2 uptake of the epithelium is cells in the response to both compounds. linked to the density of MFX. (Supported by Prog. Finaliz.: Ingegneria Genetica e Basi Molecolari delle Malattie Ereditarie, C.N.R. Rome).
EF 27 EF 26 DEGENERATIVE CHANGES IN THE SENSORY EPITHELIALKALINIZATION INDUCED HYPERPOLARIZATION P. Teunis, MEMBRANE POTENTIAL UM OF CATFISH ELECIRORECEPTORS. (DHIH) OF THE PERITUBULAR The (V ) of NECTURUS PROXIMAL TUBULE IS REDUCEDLab. Comp. Physiology, Univ. of Utrecht, Netherlands. IN1 THE ABSENCE OF SUBSTRATES.P.S. Steels, and M. Granitzer, LUC, Univ. campus, B-3610 The electroreceptive cells of a small pit Dipenbeek, Belgie. organ in the freshwater catfish Ictalurus nebulosus LeS. all project onto one afferent Necturus kidneys were artificially perfused nerve fiber. We have studied the consequences with HCOZ-free Hepes buffered salt solution sencontainin the following substrates in mM: of denervation on: spontaneous activity, sitivity to sinusoidal stimuli and latency of 3.6 lactate, 3 butyric acid, 2.22 alucose. 0.5 alanine, 6.5 glutamine, 0.2 lysine and the pulse reponse. Within 6 to 8 hrs following denervation the spontaneous frequency 0.05 glutaminic acid. Acute peritubular withwhile the sensitivity drawal of all substrates except glucose at pH decreases dramatically, as the latency to a pulse stimulus 7.5 induced a depolarization of V of +18 mv. as well Sudden peritubular addition of th& same sub- remain largely unchanged. This points to the existence of two separate mechanisms for the to kidneys perfused with glucose strates and the modulaalone hyperpolarized Vl, with -6 mv. pHIH due generation of the spike-train of this activity. Within 24 to 36 hrs. to a short-term change in peritubular pH from tion activity has ceased. 7.5 to 8.5 was 55% reduced in the absence of after denervation all The results are analyzed in terms of a stothe above mentioned substrates except gluchastical model with emphasis on the change case . in synaptic events taking place in the time course of degeneration.