Calcium Imaging Tools
Calcium imaging refers to the use of calcium ion indicators to monitor the concentration of calcium ions in cells, tissues or culture media. This technique is widely used to study calcium signaling in neuronal activity in vivo and in vitro.
Calcium ion is an essential intracellular messenger in mammalian neurons. In the resting state, the intracellular calcium ion concentration of most neurons is about 50-100 nM, which can increase 10-100 times during electrical activity. As an intracellular signal, calcium ions can trigger responses, such as altering gene expression and the release of neurotransmitters in synaptic vesicles. Because there are ion pumps in cells that selectively transport these ions under various signal stimuli, the intracellular calcium concentration is highly dynamic. Calcium imaging technology uses the advantages of calcium ion flow and special fluorescent dyes or protein fluorescent probes (calcium indicator) to directly visualize calcium signals on living nerve cells, so as to achieve the purpose of monitoring neuronal activity.
At present, the calcium ion indicators that are used more often include two categories: chemical fluorescent indicators and fluorescent protein indicators. Fluorescent protein calcium indicators, also known as genetically encoded calcium indicators (GECIs), can be divided into two types. For FRET-based GECI, when calcium ions are not present in the environment, ECFP produces blue fluorescence at an excitation wavelength of 440 nm, while Venus does not produce fluorescence; and when calcium ions are present, calcium ions bind to calmodulin CaM. ECFP resonantly transfers to Venus at an excitation wavelength of 440nm, and finally produces yellow fluorescence; for Single-fluorophore GECI, in the presence of calcium, the calmodulin-M13 interaction causes a conformational change in the fluorophore environment, resulting in an increase in fluorescence emission.
Fig.1 Schematic diagram of the principle of FRET-based GECI (A) and single fluorescent protein GECI (B).
GECI is a fluorescent protein derived from green fluorescent protein (GFP) or a variant fused with calmodulin (CaM) and M13. These proteins can be easily transfected into cells and can be measured non-invasively in vivo, so this technique is widely used for imaging neural activity, T cells, etc. The following table lists commonly used GECIs.
| Variant | Description |
| GCaMP6S | Ultrasensitive GCaMP variant; slow kinetics |
| GCaMP6m | Ultrasensitive GCaMP variant; medium kinetics |
| GCaMP6f | Ultrasensitive GCaMP variant; fast kinetics |
| GCaMPARI | Efficient and irreversible green-to-red conversion upon elevated calcium concentration and simultaneous illumination |
Calcium imaging technology is mainly used in the study of the nervous system to study the changes of calcium ions in the intricate nervous system, including the following aspects:
1. In vitro study of presynaptic and postsynaptic functions. Combining calcium ion imaging and two-photon microscopy technology, the researchers found that the calcium ion signal is limited to the dendritic spines (postsynaptic sites for excitatory transmission between neurons).
2. Study the activities of dendrites and dendritic spines of neurons in vivo. By recording calcium ion signals of single dendrites and dendritic spines through calcium ion imaging, it is possible to accurately know which parts of the neuron are involved in the neuron response.
3. In vivo study of neuronal circuits in different animal models. At present, calcium imaging technology can record the action potential of a single cell in rodents, fruit flies, nematodes, zebrafish and even primates.
4. Study the neuronal activity of behavioral animals. The development of calcium imaging technology makes it possible to record the neuronal responses of animals at rest or in motion in real time.
|
Cat |
Product Name |
Promoter |
Cell Types |
Key Components |
Fluorescent |
Expression |
| NTA-2011-ZP63 | pAAV-CAG-Flex-GCaMP6(S) | Cag | Glutamatergic Neuron | Flex-GCaMP6(S) | Inducible Cre expression | |
| NTA-2011-ZP64 | pAAV-CaMKlla-GCaMP6f-P2A-nls-dTomato | CaMKlla | Glutamatergic Neuron | GCaMP6(F) | dTomato | Normal expression |
| NTA-2011-ZP65 | pAAV-CaMKlla-GCaMP6f | CaMKlla | Glutamatergic Neuron | GCaMP6(F) | Normal expression | |
| NTA-2011-ZP66 | pAAV-CaMKlla-GCaMP6s | CaMklla | Glutamatergic Neuron | GCaMP6(S) | Normal expression | |
| NTA-2011-ZP67 | pAAV-CaMilla-GCaMP6s-P2A-nls-dTomato | CaMKlla | Broad spectrum | GCaMP6(S) | dTomato | Normal expression |
| NTA-2011-ZP68 | AAV-CMV-GCaMP6(F) | CMV | Broad spectrum | GCaMP6(F) | Normal expression | |
| NTA-2011-ZP69 | pAAV-CMV bGlobin-GCaMP6(S)- 3Flag | CMV-bGlobin | Broad spectrum | GCaMP6(S) | 3Flag | Normal expression |
| NTA-2011-ZP70 | pAAV- EF1a-DI0-GCaMP6f-P2A-nls-dTomato | EF1a | Broad spectrum | DIO-GCaMP6f | dTomato | Inducible Cre expression |
| NTA-2011-ZP71 | pAAV-EF1a-DIO-GCaMP6s-P2A-nls-dTomato | EF1a | Neuron | DIO-GCaMP6f | dTomato | Inducible Cre expression |
| NTA-2011-ZP72 | pAAV-hSyn-GCaMP6(F) | hSyn | Neuron | GCaMP6(F) | Normal expression | |
| NTA-2011-ZP73 | pAAV-hSyn1-mRuby2-GSG-P2A-GCaMP6F-WPRE -PA | hSyn | Neuron | GCaMP6(F) | mRuby2 | Normal expression |
| NTA-2011-ZP74 | pAAV-hSyn-Flex- GCaMP6f | hSyn | Neuron | GCaMP6(F) | Normal expression | |
| NTA-2011-ZP75 | pAAV-hSyn1-GCaMP6f-P2A-nls-dTomato | hSyn | Neuron | GCaMP6(F) | dTomato | Normal expression |
| NTA-2011-ZP76 | pAAV-hSyn1-GCaMP6s-P2A-nls-dTomato | hSyn | Neuron | GCaMP6(S) | nls-dTomato | Normal expression |
| NTA-2011-ZP77 | pAAV-hSyn-GCaMP6s | hSyn | Neuron | GCaMP6(S) | Normal expression | |
| NTA-2011-ZP78 | pAAV-hSyn1-mRuby2-GSG-P2A-GCaMP6s-WPRE -pA | hSyn | Neuron | GCaMP6(S) | mRuby2 | Normal expression |
| NTA-2011-ZP79 | pAAV-hSyn-Flex-GCaMP6s | hSyn | Neuron | GCaMP6(S) | Normal expression |
How to use calcium virus imaging tools for research?
Step1: Choose the appropriate calcium ion indicator
Calcium ion indicators are divided into chemiluminescent indicators and GECI indicators. Among them, GECI indicators GCaMP6f and GCaMP6s are widely used in in vivo calcium imaging research.Step2: Transport the calcium ion indicator to the target site
The chemiluminescent indicator is usually pierced by an electrode or entered into the target site by means of acetoxymethyl and dextrose, while the GECI indicator is mainly introduced to the target site by means of viral infection.Step3: Collect signals and record the results
Calcium imaging technology is usually used in conjunction with microscopy to record changes in calcium ions.
Fig.2 In Vivo Calcium Imaging.
In addtion to providing neural viral vector tracers, Creative Biolabs also offers relevant AAV packaging services. For the pre-made AAV tools, please contact us for more details.
