Using Hippocampal Slices to Study How Aging Alters Ion Regulation in Brain Tissue

Roberts, Eugene

doi:10.1006/meth.1999.0768

Cited by 8 publications

(3 citation statements)

References 35 publications

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“…While the latter category is very promising, only limited practical examples of ratio-able emission systems have found an application prior to the development in the early 1990s of benzo[ c ]xanthene dyes such as carboxy seminaphthofluoresceins (SNAFLs) and carboxy seminaphthorhodafluors (carboxy SNARFs) . Among these indicators, carboxy SNARF-1 has found numerous applications in cellular biology, − owing to the suitability of its p K a (∼7.5) for measurements under physiological conditions. Fluorination of carboxy seminaphthorhodafluors was further performed to lower the p K a value of carboxy SNARF-1.…”

Section: Introductionmentioning

confidence: 99%

Carboxy SNARF-4F as a Fluorescent pH Probe for Ensemble and Fluorescence Correlation Spectroscopies

Marcotte

Brouwer

2005

J. Phys. Chem. B

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The optical spectroscopic properties of 1,4(and 5)-benzenedicarboxylic acid, 2-[10-(dimethylamino)-4-fluoro-3-oxo-3H-benzo[c]xanthen-7-yl] (carboxy SNARF-4F), a commercial promising fluorescent pH probe, are investigated in buffered aqueous solutions in the 5.6-8.2 pH range by steady-state and time-resolved spectroscopy. A multiexponential global analysis of the picosecond time-resolved data is performed. The nonprotonated A species decays monoexponentially (0.73 ns), while the protonated species AH decays following a biexponential law with time constants of 0.40 and 1.87 ns. A kinetic scheme is proposed to explain the observations, which involves AH in equilibrium with a species denoted Y. The nature of Y is discussed in terms of a possible structural change in the molecule producing the lactone form, although the formation of a hydrogen-bonded complex to the solvent cannot be ruled out. Finally, the ability of the dye to probe pH at the single-molecule level is explored using fluorescence correlation spectroscopy.

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Section: Introductionmentioning

confidence: 99%

Carboxy SNARF-4F as a Fluorescent pH Probe for Ensemble and Fluorescence Correlation Spectroscopies

Marcotte

Brouwer

2005

J. Phys. Chem. B

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“…The currently available methods for measuring pH i include pH-sensitive microelectrodes, 31 P NMR spectroscopy, and pH-sensitive fluorescence probes (Tsien, 1989). We used carboxylseminaphthorhodafluo-1 (SNARF-1), a single-excitation, dual-emission fluorescent pH indicator (Tsien, 1989;Muller-Borer et al, 1998;Roberts, 1999), to study the interaction between pH i and seizure onset and termination. Fluorescence microscopy with pH-sensitive fluorophores allows pH i changes to be measured with temporal and spatial resolutions that surpass microelectrodes or NMR, respectively (Muller-Borer et al, 1998).…”

mentioning

confidence: 99%

Activity-Dependent Intracellular Acidification Correlates with the Duration of Seizure Activity

Xiong¹,

2000

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Synchronized neuronal activity (seizures) can appear in the presence or absence of synaptic transmission. Mechanisms of seizure initiation in each of these conditions have been studied, but relatively few studies have addressed seizure termination. In particular, how are seizures terminated in the absence of synaptic activity where there is no loss of excitatory drive or augmentation of inhibitory inputs? We have studied dynamic activity-dependent changes of intracellular pH in the absence of synaptic transmission using the fluorescent pH indicator carboxylseminaphthorhodafluo-1. During epileptiform activity we observed intracellular acidification, whereas between seizures the intracellular pH recovered. Experimental conditions that shortened the epileptiform discharge correlated with more rapid intracellular acidification. On the other hand, experimental manipulation of intracellular pH altered the duration of the seizure discharge, with acidification resulting in early termination of the epileptiform activity. These data show a direct relationship between the level of intracellular acidification and the duration of the seizures, suggesting that an intracellular pH-dependent process can terminate nonsynaptic neuronal synchronization.

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“…Can changes in intracellular pH drive alterations in protein arginine methylation? To begin to address this question we used NH 4 Cl to produce a transient intracellular alkalinization (Raley-Susman et al, 1991) in retinoic acid-differentiated mouse P19 cells.The alkalinization was monitored using SNARF-1AM, one of a family of fluorescent indicator dyes the ratio of whose emission wavelengths change as a function of pH (Roberts, 1999). Quite simply cells were loaded with SNARF-1AM and after a specified time the unabsorbed dye was washed out.…”

Section: Transient Increases In Intracellular Ph Produce Sustained Chmentioning

confidence: 99%

pH uniquely modulates protein arginine methylation

Xie¹

2011

J. Biophys. Struct. Biol.

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Protein arginine methyltransferases (PRMTs) function in the alkaline milieu of the nucleus and at neutral pH of the cytosol. Accordingly, several PRMTs are broadly active over a range of pHs. We investigated the effect altering pH had on protein arginine methylation using a variety of defined substrates, recombinant PRMTs and cell extracts.We demonstrate that pH-induced alterations in the extent of methylation and the methyl-product formed depend both on the particular substrate assayed and the PRMT that modifies it. We also find that transient intracellular alkalinization of mouse embryonic P19 neurons by NH 4 Cl results in sustained changes in substrate methylation. Altogether our results are consistent with a hypothesis in which altered substrate methylation resulting from pHinduced changes of PRMT activities coupled with low levels of demethylation may provide the longterm tag(s) necessary for the formation and maintenance of "molecular memory".

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Using Hippocampal Slices to Study How Aging Alters Ion Regulation in Brain Tissue

Cited by 8 publications

References 35 publications

Carboxy SNARF-4F as a Fluorescent pH Probe for Ensemble and Fluorescence Correlation Spectroscopies

Carboxy SNARF-4F as a Fluorescent pH Probe for Ensemble and Fluorescence Correlation Spectroscopies

Activity-Dependent Intracellular Acidification Correlates with the Duration of Seizure Activity

pH uniquely modulates protein arginine methylation

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