Calcium Imaging of Cortical Neurons using Fura-2 AM
Calcium imaging using Fura-2 AM has revolutionized the field of neuroscience by providing researchers with a powerful tool to investigate the intricate workings of cortical neurons. The technique involves the use of a fluorescent dye, Fura-2 AM, which is able to selectively bind to calcium ions within the neurons. This binding allows for the visualization and measurement of calcium levels, which are crucial for neuronal activity.
The process begins by loading the Fura-2 AM dye into the neurons. This is achieved by incubating the cells with a solution containing the dye, which can easily penetrate the cell membrane due to its lipophilic nature. Once inside the neurons, the Fura-2 AM is enzymatically cleaved, resulting in the formation of Fura-2, the active form of the dye.
To excite the Fura-2 dye, researchers use specific wavelengths of light. When illuminated with light at a wavelength of 340 nm, the dye emits a fluorescence signal at 510 nm. Similarly, when excited with light at a wavelength of 380 nm, the dye emits a fluorescence signal at 510 nm. By measuring the ratio of the fluorescence signals at these two wavelengths, researchers can determine the relative concentration of calcium ions within the neurons.
Changes in fluorescence intensity indicate changes in calcium levels, providing valuable insights into the activity of cortical neurons. For example, an increase in fluorescence intensity suggests an increase in calcium levels, which is often associated with neuronal activation. Conversely, a decrease in fluorescence intensity indicates a decrease in calcium levels, which may be indicative of neuronal inhibition or suppression.
By studying the dynamics and function of cortical neurons using calcium imaging, researchers can gain a deeper understanding of various neurological processes and disorders. For instance, this technique has been used to investigate synaptic plasticity, which is the ability of neurons to change their strength of communication. It has also been employed to study neuronal excitability, neuronal network activity, and the effects of drugs or genetic manipulations on neuronal function.