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1Author    Brogå, A. JohnssonRequires cookie*
 Abstract    Recent findings indicate that lithium belongs to the group of rather exclusive agents which affect the period of circadian clocks: The period of the cir­ cadian petal movements of Kalanchoe is increased by about 2 hours in 5 m M LiCl 2. In the present paper we will report an action of lithium on a much more rapid oscillation, which under certain circum­ stances occurs in stomatal regulation. These oscil­ lations are found to be remarkably slowed down by lithium, in analogy to the circadian oscillations of Kalanchoe. Material and Methods 
  Reference    (Z. Naturforsch. 29c, 298 [1974]; received February 11 1974) 
  Published    1974 
  Keywords    Lithium, Stomata, Plant Rhythm, Cell Permeability 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0298_n.pdf 
 Identifier    ZNC-1974-29c-0298_n 
 Volume    29 
2Author    H. Stieve, M. Pflaum, J. Klomfaß, H. G. AubeRequires cookie*
 Title    Calcium/Sodium Binding Competition in the Gating of Light-Activated Membrane Conductance Studied by Voltage Clamp Technique in Limulus Ventral Nerve Photoreceptor  
 Abstract    The mem brane current vs. voltage dependence was measured in Limulus ventral nerve photo­ receptors at various external C a2+ and N a+ concentrations, using the voltage clam p technique. Lowering the external concentration of the divalent cations Ca~+ and Mg+ to < 1 |im ol/l by adding EDTA causes 1) the light-induced transient conductance increase to disappear and 2) Irev J d ! the reversal potential of the mem brane current in the dark to shift to a positive value between + 10 and + 2 0 mV. This value is about the same as the (V^J-l), reversal potential of the total light current under normal ionic conditions. If the external N a+ is lowered to 50 mmol/1 (i.e. 10% of the normal concentration) simultaneously with the lowering o f the divalent cation concentration described above, the light response is not abolished and V TevJ p is shifted less. The extent of this antagonism depends on the sodium sub­ stitute; it is stronger if choline is used instead of lithium. Lowering of sodium alone to 50 mmol/1, in a saline containing normal C a2+ and Mg2+ concen­ trations, does not change the mem brane dark current vs. voltage curve and so is not altered; VT ^ A J L, the reversal potential of the light-induced current, however, is reduced by 10 mV (from + 2 0 to + 1 0 mV). This reduction in %evA JL can be accounted for by the reduction of the sodium gradient across the cell membrane. Raising the external C a2+ concentration to 40 or 100 mmol/1 has no conspicuous effect on the mem brane current vs. voltage dependence and the gating o f the light-induced conductance in­ crease. The results are consistent with our working hypothesis that the gating o f the light-activated ion channels in Limulus photoreceptor is controlled by negative binding sites for which calcium-and sodium ions compete with antagonistic actions. Abbreviations: ReP, receptor potential (m embrane voltage response to the light stimulus); HMAX [mV], peak am pli­ tude of the ReP; PMP [mV], pre-stimulus mem brane po­ tential (difference between the extracellularly recorded zero line and the intracellularly recorded base line; initial and final zero were averaged to compensate for drift); VM [mV], mem brane voltage; J M [nA], mem brane current; J d [nA]» dark current, m em brane current during voltage clamp, measured 1 s after clam p onset; J L [nA], am plitude o f total light current; am plitude of total m em brane current following the light flash (J D + A JL)\ AJL, am plitude of light-induced current; ^ ev7D [mV], reversal potential of dark current; ^ ev7 L[mV], reversal potential of light cur­ rent; I(evj y L[mV], reversal potential of the light-induced current evoked by the light stimulus; g G [|iS], membrane (slope) conductance in the dark; ^lD 1^], total membrane (slope) conductance during illum ination; J g L[|iS], light induced mem brane (slope) conductance; PS, physiological saline (see Table I); [N a+]ex[Ca2+]ex, sodium, or calcium ion concentration of the external saline; EDTA, ethylene dimethyl tetra acetic acid; EGTA, ethylene glycol-bis (2-aminoethylether) N ,N '-tetra acetic acid. 
  Reference    Z. Naturforsch. 40c, 278—291 (1985); received N ovember 19 1984 
  Published    1985 
  Keywords    Limulus Ventral Nerve Photoreceptor, Current-Voltage Relation, Varied External Calcium and Sodium Concentration, Calcium /Sodium Binding Competition, Lithium 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0278.pdf 
 Identifier    ZNC-1985-40c-0278 
 Volume    40 
3Author    Hennig Stieve, Gabriele Rüsing, Weijia Yuan, H.Thomas HennigRequires cookie*
 Title    The Effects of Externally Applied Lithium and Strontium on the Arsenazo-Monitored Cytosolic Calcium Signal of the Limulus Ventral Photoreceptor  
 Abstract    The intracellular arsenazo signal indicating the transient light-evoked change in cytosolic Ca2+ (or Sr2+) concentration was measured in Lim ulus ventral photoreceptor simultaneously with the receptor potential at 15 °C. The decline of the arsenazo signal has two phases (D 1 and D 2) when the photoreceptor is bathed in physiological saline. 1. When calcium is replaced by strontium in the superfusate both receptor potential and arsenazo signal are markedly increased in amplitude and the membrane potential is hyper­ polarized. The decline of the arsenazo signal is prolonged and becom es monophasic; the fast phase D 1 of the decline disappears. 2. In strontium saline under voltage clamp conditions the slope o f the monophasic decline of the arsenazo signal is the steeper the more negative the membrane voltage. 3. After replacing sodium by lithium in the superfusate the rise of the receptor potential and of the arsenazo signal are not much altered. The decline of the arsenazo signal, however, is slowed down more than 3-fold; this is due to the complete suppression of the fast phase D1 and the retardation o f the slow phase D 2 of the calcium re-decline. Interpretation: 1. The N a -C a exchanger can accept strontium as a calcium substitute. Strontium has a weaker desensitizing action than calcium. Strontium is not -or only very little -taken up by the endoplasmic cisternae. 2. In sodium-free lithium saline the N a -C a exchanger, the N a -K ATPase and the calcium uptake system of the endoplasmic cisternae do not function. Therefore the intracellular calcium level rises. Abbreviations: Arsenazo III, 2,2'-(l,8-dihydroxy-3,6-di-sulfo-2-naphthalene-bis(azo)dibenzenearsonic acid; AS, arsenazo signal; cGMP, guanosine 3':5'-cyclic m ono­ phosphate; D l , D 2 , fast and slow phase o f decline of the arsenazo signal; EGTA, ethylene glycol-bis(ß-aminoethylether)-N,N,N',N'-tetraacetic acid; calcium chelating agent; F, area, time integral of light-evoked sig­ nal; Hmax, peak height of a light-evoked signal; IP3, ino­ sitol 1,4,5-trisphosphate; Mi, initial slope, mean slope of rise from end of latency until half height o f the signal; Mm, median slope of rise, slope of rise at half height of the signal; PMP, prestimulus membrane potential; PS, physiological saline; ReP, receptor potential, light-evoked membrane voltage signal; SRC, subrhabdomeric cisternae; Tlat, latency, time from stimulus onset to first significant start of the response; Tmax, time-to-peak from stimulus onset; Tr, rise time (Tmax -Tlat); T2, decay time, time during which the response decays from its maximum to 50% of that value. 
  Reference    Z. Naturforsch. 49c, 372 (1994); received March 14 1994 
  Published    1994 
  Keywords    Limulus Photoreceptor, R eceptor Potential, Intracellular Arsenazo Signal, Cytosolic Calcium or Strontium Transient, Lithium 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0372.pdf 
 Identifier    ZNC-1994-49c-0372 
 Volume    49 
4Author    Anders Johnsson, Wolfgang Engelmann, Burkhard Pflug, W. Aldem, Ar KlemkeRequires cookie*
 Title    Influence of Lithium Ions on Human Circadian Rhythms  
 Abstract    Lithium carbonate lengthens the circadian period in humans under temporal isolation (arctic summer four groups. L i+ ions are known to change the period length of several circadian rhythm s in plants and animals [1], In all cases reported so far the effect is a lengthening o f the free running period. An experiment has been performed on a single person in an isolation unit to test whether L i+ acts on hum an circadian rhythms and the results provided have not been conclusive [2]. We have conducted an experiment to determine the influence o f L i+ on the hum an circadian system under arctic sum m er conditions. The continuous light and abscence o f other 24 h tim e cues allows free run o f hum an circadian rhythms [3]. In this brief report, we present some salient results of the effects of Li+ on the tem perature-, sleep-wakefulness-, and activity rhythm in some humans. More details of this investigation will be published elsewhere. 
  Reference    Z. Naturforsch. 35c, 503—507 (1980); received January 14 1980 
  Published    1980 
  Keywords    Dedicated to Prof C H Hertz, Lund University, Sweden, on His 60th Birthday Circadian Rhythms, Lithium, Body Temperature, Activity, Svalbard-Spitsbergen 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0503.pdf 
 Identifier    ZNC-1980-35c-0503 
 Volume    35