Calcium transients

FIGURE 5.6 Calcitonin receptor responses, (a) Real-time melanin dispersion (reduced light transmittance) caused by agonist activation (with human calcitonin) of transfected human calcitonin receptors type II in melanophores. Responses to 0.1 nM (filled circles) and lOnM (open circles) human calcitonin, (c) Dose-response curves to calcitonin in melanophores (open circles) and HEK 293 cells, indicating calcium transient responses (filled circles). 

Practical problems with hemi-equilibria can be avoided by allowing sufficient time for equilibrium to occur. However, there are some situations where this may not be possible. One is where the functional system desensitizes during the span of time required for equilibrium to be attained. Another is where the actual type of response being measured is transitory and where the only measurement of calcium transients where a spike of effect is the only response observed in the experimental system. 

Freeman, G., and Ridgway, E. B. (1987). Endogenous photoproteins, calcium channels and calcium transients during metamorphosis in hydrozoans. Roux s Arch. Dev. Biol. 196 30-50. 

Ridgway, E. B., and Ashley, C. C. (1967). Calcium transients in single muscle fibers. Biochem. Biophys. Res. Commun. 29 229-234. 

Figure 6. Effect of hyperosmolality on FMLP-induced calcium transients in indo-l-loaded neutrophils. Cells were incubated at 37°C in either regular buffer (A) regular buffer plus 0.15-ilf sodium sulfate, 662 mosmol/kg (B) 0.3-M sodium HEPES, 645 mosmol/kg (C) or 0.45-jy sucrose, 870 mosmol/kg (D). All were treated with 5 M8/ > cytochalasin B and stimulated with 10 M FMLP. Excitation at 340 nm and emission at 400 nm.

In addition to the pre-synaptic effects, CX3CL1 modulates the functional properties of ligand-gated channels at post-synaptic sites. In SK-N-SH cells, a human neuroblastoma cell line, CX3CL1 reduces the amplitude of NMDA-induced calcium transients (Deiva et al. 2004). In these cells, CX3CL1 application causes a PTX insensitive transient increase in the intracellular Ca " concentration dependent on... 

Wu S et al. (2001) Cardiac effects of the extract and active components of Radix stephaniae tetrandrae. I. Electrically induced intracellular calcium transient and protein release during the calcium paradox. Life Sci 68(25) 2853-2861... 

Figure 4.7 Changes in intraceiiuiar calcium in cultured rat ventricular myocytes exposed to oxidant stress. Calcium was measured using the fluorescent probe Fura>2. The ratio of the Fura-2 fluorescence measured at 340 and 380 nm excitation is shown and this is proportional to the intracellular calcium concentration. The fast-speed traces shown (note the 3.5 s time-scale) were recorded after various durations of oxidant stress. Myocytes under control conditions (before t = 0) show spontaneous calcium transients. These transients decreased in frequency with oxidant stress until cells failed to show spontaneous activity but continued to maintain a low intracellular calcium.

G.B. Stefano, V. Prevot, J.C. Beauvillain, C. Fimiani, I. Welters, R Cadet, C. Breton, J. Pestel, M. Salzet, and T.V. Bilfinger, Estradiol coupling to human monocyte nitric oxide release is dependent on intracellular calcium transients evidence for an estrogen surface receptor. J. Immunol. 163, 3758-3763 (1999). 

I. Welters, and M. Salzet, Estradiol-stimulated nitric oxide release in human granulocytes is dependent on intracellular calcium transients evidence of a cell surface estrogen receptor. Blood 95, 3951-3958 (2000). 

Kitazawa T, Kobayashi S, Horiuti K, Somlyo AV, Somlyo AP 1989 Receptor coupled, permeabilized smooth muscle role of the phosphatidylinositol cascade, G proteins and modulation of the contractile response to Ca2+. J Biol Chem 264 5339-5342 Lopez-Lopez JR, Shacklock PS, Balke CW, Wier WG 1995 Local calcium transients triggered by single L-type calcium channel currents in cardiac cells. Science 268 1042-1045 Marks AR, Fleischer S, Tempst P 1990 Surface topography analysis of the ryanodine receptor/ junctional channel complex based on proteolysis sensitivity mapping. J Biol Chem 265 13143-13149... 

However, the dissociation constant Kq) does depend on pH, ionic strength, and the concentration of free Mg +, which need to be estimated independently. 5FBAPTA has been used extensively [308] in studies of cells [306,309,310], and the perfused beating heart, revealing calcium transients during the myocardial cycle (Fig. 11) [311-313]. Kirschenlohr et al. [313] reported that developed pressure in the perfused heart was reduced after addition of 5FBAPTA, but this could be reversed by including 50 pM ZnC in the perfusion medium. 

Allen, S., Khan, S., Al-Mohanna, F., Batten, P., and Yacoub, M. (1998). Native low density lipoprotein-induced calcium transients trigger VCAM-1 and E-selectin expression in cultured human vascular endothelial cells. ]. Clin. Invest. 101,1064—1075. 

Xiong Z, O Hanlon D, Becker LE, Roder J, MacDonald JF, Marks A. 2000. Enhanced calcium transients in glial cells in neonatal cerebellar cultures derived from S100B null mice. Exp Cell Res 257(2) 281-289. 

Piacentino, V. 3rd, Weber, C.R., Chen, X., et al., 2003, Cellular basis of abnormal calcium transients of failing human ventricular myocytes. Circ Res., 92(6), pp 651-8. 

Lambe E, Aghajanian GK (2003) Hypocretin (orexin) induces calcium transients in single spines postsynaptic to identified the boutons in prefrontal slice. Neuron 40 139-50 Li Y, Gao XB, Sakurai T et al (2002) Hypocretin/orexin excites hypocretin neurons via a local glutamate neuron - a potential mechanism for orchestrating the hypothalamic arousal system. Neuron 36 1169-81... 

Fossier P, Tauc L, Baux G (1999) Calcium transients and neurotransmitter release at an identified... 

O Donnell, J. M., Sumbilla, C. M., Ma, H. et al. (2001). Tight control of exogenous SERCA expression is required to obtain acceleration of calcium transients with minimal cytotoxic effects in cardiac myocytes. Circ. Res. 88(4), 415-421. 

Leinders-Zufall T., Greer C. A., Shepherd G. M. and Zufall F. (1998a) Imaging odor-induced calcium transients in single olfactory ciha specificity of activation and role in transduction. J. Neurosci. 18, 5630-5639. 

Robinson, H. P., Kawahara, M., Jimbo, Y., Torimitsu, K., Kuroda, Y., and Kawana, A. (1993). Periodic synchronized bursting and intracellular calcium transients elicited by low magnesium in cultured cortical neurons. J. Neurophysiol. 70, 1606—1616. 

Lambe EK, Aghajanian GK. Hypocietin (orexin) induces calcium transients in single spines postsynaptic to identified thalamocortical boutons in prefrontal slice. Neuron 2003 40(1) 139-150. 

Fig. 9.1 Top action potentials computed using a model of a guinea-pig ventricular cell. Middle computed ionic currents. Bottom computed calcium transients. 90% block of the fast component of /k prevents repolariztion and generates multiple after-depolarizations [10].

Eisner, J., Oppermann, M Czech, W., Dobos, G., Schopf, E., Norgauer, J., and Kapp, A. (1994) C3a activates reactive oxygen radical species production and intracellular calcium transients in human eosinophils. Eur. J. Immunol. 24, 518-522. 

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