Double caged GABA compounds, bis-CNB-GABA
Double caged GABA compounds and compositions including the same are described. Methods of synthesizing and using double caged GABA compounds are provided.
1. A composition comprising a double-caged GABA compound comprising gamma-amino butyric acid covalently linked to a first photosensitive protecting group linked to a carboxyl of the gamma-amino butyric acid and a second photosensitive protecting group linked to an amine of the gamma-amino butyric acid, wherein
the first and second photosensitive protecting groups are independently selected from the group consisting of: nitrobenzyl (NB), nitrophenyl ethyl (NPE), α-carboxy-2-nitrobenyzl (CNB), 4,5-dimethoxy-2-nitrobenzyl (DMNB), (4,5-dimethoxy-2-nitrophenyl)ethyl (DMNPE), 4-methoxy-7-nitroindoline (MNI), 4-carboxymethoxy-5,7-dinitroindolinyl (CDNI), 6-bromo-7-hydroxycoumarin-4-ylmethoxycarbonyl (Bhc), ruthenium-bipyridine-triphenylphosphine (RuBi), and carboxynitrobenzyl, and
the double-caged GABA compound is biologically inert before exposure to light, and the first photosensitive protecting group and the second photosensitive protecting group cleave from the gamma-amino butyric acid by photolysis upon exposure of the double-caged GABA compound to light.
2. The composition of claim 1 , wherein the group selected as the first photosensitive protecting group is the same group as selected the second photosensitive protecting group.
3. The composition of claim 1 , wherein the first photosensitive protecting group or any byproduct thereof and the second photosensitive protecting group or any byproduct thereof is biologically inert after exposure to light and cleavage from the double-caged GABA compound.
4. The composition of claim 1 , wherein the double-caged GABA compound has the structure of Formula I:
or a salt thereof.
5. The composition of claim 1 , wherein the double-caged GABA compound is soluble in an aqueous solution.
6. The composition of claim 1 , wherein light has a wavelength in a range from 250 nm to 500 nm.
7. A method of synthesizing a double-caged GABA compound according to claim 1 comprising conjugating the first photosensitive protecting group and the second photosensitive protecting group to a gamma-amino butyric acid.
8. The method of claim 7 , wherein the first photosensitive protecting group is conjugated to the carboxyl of the gamma-amino butyric acid.
9. The method of claim 7 , wherein the second photosensitive protecting group is conjugated to the amine of the gamma-amino butyric acid.
10. The method of claim 7 , wherein the first photosensitive protecting group and the second photosensitive protecting groups are simultaneously conjugated to the gamma-amino butyric acid at the carboxy position and the amine position, respectively.
11. The method of claim 7 , wherein prior to conjugating the first photosensitive protecting group and the second photosensitive protecting groups are included in an intermediate compound.
12. The method of claim 11 , wherein conjugating includes combining the intermediate compound and the gamma-amino butyric acid in a solvent to form a mixture and providing an inert gas over the mixture.
13. The method of claim 12 further comprising allowing the mixture to react for 1 hour to 25 hours.
14. The method of claim 11 , wherein the intermediate compound is benzyl bromide.
15. A method of chemical stimulation of a biological sample comprising: adding a double-caged GABA compound according to claim 1 to the biological sample and exposing the double-caged GABA compound in the biological sample to light.
16. The method of claim 15 , wherein the biological sample is selected from the group consisting of: cells, neurons, a tissue, and a slice of brain tissue.
17. The method of claim 16 , wherein the biological sample is the slice of brain tissue.
18. The method of claim 15 , wherein the double-caged GABA compound has the structure of Formula I:
or a salt thereof.
19. The method of claim 15 , wherein the double-caged GABA compound is exposed to light selected from the group consisting of: UV light, pulsed infrared light, and visible light.
20. The method of claim 15 , wherein the double-caged GABA compound is exposed to light in a range from 250 nm to 500 nm wavelength.
21. The method of claim 15 , wherein the double-caged GABA compound is exposed to light for a period from 0.001 ms to 1000 ms.
22. The method of claim 15 further comprising measuring the effect of chemical stimulation in a biological sample.
23. The method of claim 21 , wherein measuring the effect of chemical is stimulation includes at least one parameter selected from the group consisting of: whole-cell ionic current, AMPA or GABA receptor density, correlation between AMPA or GABA receptor density and spine location, neuron connectivity, synaptic input and neuronal output.
24. The method of claim 21 , wherein measuring includes at least one procedure selected from the group consisting of: measuring an extinction coefficient, determining quantum yield, whole-cell patch clamp recording, imaging intracellular second messengers, and measuring intensity of illumination.
25. The composition of claim 1 , wherein the first photosensitive protecting group is nitrobenzyl (NB) and second photosensitive protecting groups is nitrobenzyl (NB).
26. The composition of claim 1 , wherein the first photosensitive protecting group is nitrophenyl ethyl (NPE) and second photosensitive protecting groups is nitrophenyl ethyl (NPE).
27. The composition of claim 1 , wherein the first photosensitive protecting group is α-carboxy-2-nitrobenyzl (CNB) and second photosensitive protecting groups is α-carboxy-2-nitrobenyzl (CNB).
28. The composition of claim 1 , wherein the first photosensitive protecting group is 4,5-dimethoxy-2-nitrobenzyl (DMNB) and second photosensitive protecting groups is 4,5-dimethoxy-2-nitrobenzyl (DMNB).
29. The composition of claim 1 , wherein the first photosensitive protecting group is (4,5-dimethoxy-2-nitrophenyl)ethyl (DMNPE) and second photosensitive protecting groups is (4,5-dimethoxy-2-nitrophenylethyl (DMNPE).
30. The composition of claim 1 , wherein the first photosensitive protecting group is 4-methoxy-7-nitroindoline (MNI) and second photosensitive protecting groups is 4-methoxy-7-nitroindoline (MNI).
31. The composition of claim 1 , wherein the first photosensitive protecting group is 4-carboxymethoxy-5,7-dinitroindolinyl (CDNI) and second photosensitive protecting groups is 4-carboxymethoxy-5,7-dinitroindolinyl (CDNI).
32. The composition of claim 1 , wherein the first photosensitive protecting group is 6-bromo-7-hydroxycoumarin-4-ylmethoxycarbonyl (Bhc) and second photosensitive protecting groups is 6-bromo-7-hydroxycoumarin-4-ylmethoxycarbonyl (Bhc).
33. The composition of claim 1 , wherein the first photosensitive protecting group is ruthenium-bipyridine-triphenylphosphine (RuBi) and second photosensitive protecting groups is ruthenium-bipyridine-triphenylphosphine (RuBi).
34. The composition of claim 1 , wherein the first photosensitive protecting group is carboxynitrobenzyl and second photosensitive protecting groups is carboxynitrobenzyl.