Approximate Analytical Time-Dependent Solutions to Describe Large-Amplitude Local Calcium Transients in the Presence of Buffers

Mironova, Lidia A.; Mironov, S. L.

doi:10.1529/biophysj.107.113340

Cited by 13 publications

(14 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In many neurons (Larkum et al 2003; Augustine et al 2003; Hagenston et al 2008), the propagation of Ca 2+ waves is supported by Ca 2+ ‐induced Ca 2+ release (CICR) from internal stores. The measured speed agrees with values which were obtained in other neurons (reviewed by Augustine et al 2003) and with theoretical estimates of the velocity of calcium waves supported by CICR (Mironova & Mironov, 2008). When calcium waves crossed the soma, the activity of TRPM4‐like channels transiently increased.…”

Section: Resultssupporting

confidence: 89%

Metabotropic glutamate receptors activate dendritic calcium waves and TRPM channels which drive rhythmic respiratory patterns in mice

Mironov

2008

The Journal of Physiology

111

207

View full text Add to dashboard Cite

Respiration in vertebrates is generated by a compact network which is located in the lower brainstem but cellular mechanisms which underlie persistent oscillatory activity of the respiratory network are yet unknown. Using two-photon imaging and patch-clamp recordings in functional brainstem preparations of mice containing pre-Bötzinger complex (preBötC), we examined the actions of metabotropic glutamate receptors (mGluR1/5) on the respiratory patterns. The agonist DHPG potentiated and antagonist LY367385 depressed respiration-related activities. In the inspiratory neurons, we observed rhythmic activation of non-selective channels which had a conductance of 24 pS. Their activity was enhanced with membrane depolarization and after elevation of calcium from the cytoplasmic side of the membrane. They were activated by a non-hydrolysable PIP 2 analogue and blocked by flufenamate, ATP 4− and Gd 3+ . All these properties correspond well to those of TRPM4 channels. Calcium imaging of functional slices revealed rhythmic transients in small clusters of neurons present in a network. Calcium transients in the soma were preceded by the waves in dendrites which were dependent on mGluR activation. Initiation and propagation of waves required calcium influx and calcium release from internal stores. Calcium waves activated TPRM4-like channels in the soma and promoted generation of inspiratory bursts. Simulations of activity of neurons communicated via dendritic calcium waves showed emerging activity within neuronal clusters and its synchronization between the clusters. The experimental and theoretical data provide a subcellular basis for a recently proposed group-pacemaker hypothesis and describe a novel mechanism of rhythm generation in neuronal networks.

show abstract

Section: Resultssupporting

confidence: 89%

Metabotropic glutamate receptors activate dendritic calcium waves and TRPM channels which drive rhythmic respiratory patterns in mice

Mironov

2008

The Journal of Physiology

111

207

View full text Add to dashboard Cite

show abstract

“…The amplitude and propagation speed of the pulse is affected by the buffering capacity of the cytosol and molecular crowding (Jafri and Keizer, 1995; Dargan and Parker, 2003; Falcke, 2003; Mironova and Mironov, 2008). …”

Section: Introductionmentioning

confidence: 99%

Intracellular Signaling by Diffusion: Can Waves of Hydrogen Peroxide Transmit Intracellular Information in Plant Cells?

Vestergaard¹,

Flyvbjerg²,

Møller³

2012

Front. Plant Sci.

View full text Add to dashboard Cite

Amplitude- and frequency-modulated waves of Ca2+ ions transmit information inside cells. Reactive Oxygen Species (ROS), specifically hydrogen peroxide, have been proposed to have a similar role in plant cells. We consider the feasibility of such an intracellular communication system in view of the physical and biochemical conditions in plant cells. As model system, we use a H2O2 signal originating at the plasma membrane (PM) and spreading through the cytosol. We consider two maximally simple types of signals, isolated pulses and harmonic oscillations. First we consider the basic limits on such signals as regards signal origin, frequency, amplitude, and distance. Then we establish the impact of ROS-removing enzymes on the ability of H2O2 to transmit signals. Finally, we consider to what extent cytoplasmic streaming distorts signals. This modeling allows us to predict the conditions under which diffusion-mediated signaling is possible. We show that purely diffusive transmission of intracellular information by H2O2 over a distance of 1 μm (typical distance between organelles, which may function as relay stations) is possible at frequencies well above 1 Hz, which is the highest frequency observed experimentally. This allows both frequency and amplitude modulation of the signal. Signaling over a distance of 10 μm (typical distance between the PM and the nucleus) may be possible, but requires high signal amplitudes or, equivalently, a very low detection threshold. Furthermore, at this longer distance a high rate of enzymatic degradation is required to make signaling at frequencies above 0.1 Hz possible. In either case, cytoplasmic streaming does not seriously disturb signals. We conclude that although purely diffusion-mediated signaling without relaying stations is theoretically possible, it is unlikely to work in practice, since it requires a much faster enzymatic degradation and a much lower cellular background concentration of H2O2 than observed experimentally.

show abstract

“…In contrast, EGTA contributes to diminution of slow and diffuse elevations of Ca 2+ concentration (Ca 2+ macrodomains, [8]). The role of fast and slow calcium signals in the regulation of neurotransmission secretion in various types of synapses is an important problem in synaptology [7]. Examination of this problem using BAPTA and EGTA in neuromuscular synapses yielded contradictory results [1,6,10].…”

mentioning

confidence: 99%

Effect of Fast and Slow Calcium Buffers on Induced Secretion of Neurotransmitter

2010

View full text Add to dashboard Cite

Loading of mouse motor nerve terminals with EGTA-AM, but not with BAPTA-AM, inhibited the release of the neurotransmitter in response to stimulation of the nerve with rare (0.3 Hz) "single" pulses. During rhythmic stimulation with short (50 EPP) high-frequency (20 Hz) series, BAPTA-AM buffer modified burst pattern in a dose-dependent manner: it replaced the phase of initial facilitation by persistent depression of secretion and decreased its plateau level at the end of the burst. In contrast, loading of the nerve terminals with EGTA-AM buffer produced no effect on the phase of initial facilitation, but decreased the plateau level to the same degree as BAPTA-AM did. Probably, the different effects of both buffers on secretion of neurotransmitter reflect peculiarities of involvement of fast and slow Ca(2+)signals of motor terminals in single and rhythmic release of the neurotransmitter.

show abstract

Approximate Analytical Time-Dependent Solutions to Describe Large-Amplitude Local Calcium Transients in the Presence of Buffers

Cited by 13 publications

References 46 publications

Metabotropic glutamate receptors activate dendritic calcium waves and TRPM channels which drive rhythmic respiratory patterns in mice

Metabotropic glutamate receptors activate dendritic calcium waves and TRPM channels which drive rhythmic respiratory patterns in mice

Intracellular Signaling by Diffusion: Can Waves of Hydrogen Peroxide Transmit Intracellular Information in Plant Cells?

Effect of Fast and Slow Calcium Buffers on Induced Secretion of Neurotransmitter

Contact Info

Product

Resources

About