Question

Explain why chemogenetic based methods of regulating cellular signaling result in poor temporal control of biochemical pathways relative to optogenetic based methods.

Answer 1

Answer)Chemogenetic based methods of regulating cellular signalling result in poor temporal control of biochemical pathway relative to optogenetic based methods as:

1) (a)Chemogentic:-This term was described to elaborate the effect of mutation on isomeric activity on substrate specificity. This is used for study of relation between brain activity and behavior (b) Optogenetic:- The term, defines its meaning, refers to biological technique that utilizes light for neuronal control that have been modified genetically that expresses light sensitive ion channels that is called as opsins. These technique involves optical monitoring of behaviour of neurons

2) Chemogenetic versus Optogenetic:- Both of these method are used for studying relationship between brain activity and behaviour and target specific circuits of brain and studying their cell population,

(a) Chemogenetic utilizes Engineered receptors (chemical) and their specific molecules that target to specifc receptors and influences their activity.example:- Receptors like GPCR(G protein Coupled Receptors)(genetically modifed), DREADD( Designer recpeptors that would be activated by Designer drugs) whereas optogenetics can accomplish this modulation via light sensitive pumps or ion channels, where light delievary(focal) results in neuronal excitation. This method utilizes actuators like halorhodopsin,and channelrhodopsin

(b) Optogenetic method possess fast temporal resolution or control of neuronal activity whereas chemogentic method has poor temporal control of pathway as optogenetic method as fast temporal (resolution) of control of neuron. Optogenetic constructs(1st generation) exhibits milisecond resolution of neuronal control and thereby signalling next generation constructs stimulates neurons at greater frequency, in contrast in chemogenetic DREADD does not stimulate level of spike for temporal resolution, resulting in poor control and silencing or activation of neuron takes place in hours or minutes. This takes time for the state of activation and inactivation.

3) Example:- Fast temporal approaches are desired in seizures followed by Epilepsy, as optogenetic method can acquire fast temporal result and hence can be studied effectively whereas DREADD requires cotinuous stimulation for patients for the result.