Disease relevance of Nitr-5

• 6. The Ca2(+)-induced Ca2+ release responses obtained with nitr-5 photolysis were significantly slower than the fastest rate of tetanus development which has been recorded from intact fibres of barnacle muscle (mean half-time = 177 ms at 12 degrees C) [1].

High impact information on Nitr-5

• To delineate the roles of presynaptic potential and calcium entry in transmitter release, we have used nitr-5, a photolabile calcium chelator, and a voltage-clamp technique to control intracellular calcium and membrane potential independently at a synapse formed between cell bodies of cultured neurons of the fresh water snail Helisoma trivolvis [2].
• Photolysis of nitr-5 injected into hippocampal CA1 pyramidal cells resulted in a large enhancement of synaptic transmission [3].
• Although IM is not primarily Ca2+ dependent, small increases in [Ca2+]i by photolysis of the "caged" Ca2+ chelator nitr-5 or by evoking action potentials augmented, while larger increases inhibited, IM [4].
• Pulses of Ca2+ generated by flash photolysis of intracellularly trapped nitr-5, a "caged" Ca2+, could precipitate precocious nuclear envelope breakdown in prophase cells [5].
• Comparison of the kinetics among the chelators, which photolyze at different rates, suggests that release of Ca2+ from nitr-5 is too fast to limit the relaxation [6].

Biological context of Nitr-5

• Cardiac sarcoplasmic reticulum phosphorylation increases Ca2+ release induced by flash photolysis of nitr-5 [7].

Anatomical context of Nitr-5

• During the rising phase of the response, photolysis of DM-nitrophen (but not nitr-5) induced a pronounced facilitation in WT photoreceptors [8].
• Fluo-3 can also be microinjected into fibroblasts along with photolabile compounds such as nitr-5 and caged inositol trisphosphate for photorelease experiments [9].
• The whole-cell IK of nonpregnant myocytes respond strongly to changes in [Ca2+]o or changes in [Ca2+]i caused by photolysis of caged Ca2+ compounds, nitr 5 or DM-nitrophene, but that of late-pregnant myocytes respond weakly or not at all [10].
• 4. When intracellular Ca2+ concentration was increased by UV irradiation of the hair cell loaded with a caged Ca2+ compound, nitr-5, the closely apposed granule cell generated an outward current when voltage clamped at +55 mV [11].
• The small tonic response which remained had a shorter rise half-time than the Ca2(+)-induced Ca2+ release response and was attributed to direct activation of the myofibrils by Ca2+ released from the nitr-5 [1].

Associations of Nitr-5 with other chemical compounds

• Internal Ca2+ was elevated by flash photolysis of the Ca2+ chelator Nitr 5, and intracellular Ca2+ levels were simultaneously monitored by Fluo 3 fluorescence [12].
• Calibrations using INDO-1 and Mag-INDO-1 indicated that photolysis of DM-nitrophen (5 mM loaded with 4 mM Ca2+), raised Ca, to ca. 20-50 microM, and nitr-5 (same loading) to ca. 1-2 microM [8].
• We have studied calcium-activated potassium current, IK(Ca), and calcium-activated nonspecific cation current, INS(Ca), in Aplysia bursting pacemaker neurons, using photolysis of a calcium chelator (nitr-5 or nitr-7) to release "caged calcium" intracellularly [13].
• When two independent glutamate pipettes were aimed at different dendrites of the same Purkinje neurone, LTD induction was confined to the site at which glutamate and photolysis of nitr-5 were applied [14].
• At 2.8 mm glucose, glucagon did not affect K(ATP) channel activity until Ca2+ was released from Nitr-5 by flash photolysis, at which point channel activity was transiently suppressed [15].

Gene context of Nitr-5

• In contrast, in the aged oocyte, restoration of F480 following Nitr-5 photolysis was incomplete (115 +/- 12% of the control) and slow (time constant = 64 +/- 23 sec) [16].
• Photolysis of nitr-5, a caged calcium molecule, has been used for rapid activation of skinned fibre bundles of a myosin-regulated muscle, the striated adductor of the scallop, Pecten maximus [17].

Analytical, diagnostic and therapeutic context of Nitr-5

• Light-induced Ca2+ release from the Ca2+ complex of Nitr-5 altered the FTIR spectra of sarcoplasmic reticulum vesicles and purified Ca(2+)-ATPase preparations [18].
• Intracellular calcium concentration ([Ca2+]i) was elevated by photolysis of the caged calcium compound, Nitr-5, and by use of the intrapipette perfusion technique in hair cells dissociated from the chick cochlea [19].

References