| Abstract
| - The application of the desyl or 2-oxo-1,2-diphenylethylmoiety as a photolabile ligand for the releaseof phosphates such as cAMP and inorganic phosphate(Pi)1,2 is extended to include selectedexcitatoryamino acids. The synthesis and photochemical studies ofN- and O-desyl-caged versions of theendogenous amino acid neurotransmitters glutamate and γ-aminobutyricacid (GABA) are reported.Photolysis at 350 nm of solutions of γ-O-desylglutamate (11) and O-desyl GABA (14)in 1:1 H2O−acetonitrile cleanly produced free glutamate and GABA, respectively,with rate constants of ca.107 s-1;2-phenylbenzo[b]furan (2) was theonly photobyproduct detected by HPLC. Photolysisquantum efficiencies for the disappearance of O-desyl aminoacid esters were in the range of 0.29−0.31, and the appearance efficiencies of furan 2 (and thecorresponding amino acid) were 0.14.The photolysis of 14 was efficiently quenched withsodium 2-naphthalenesulfonate, yielding a tripletlifetime of ca. 10 ns. Photolysis of 11 in mammalian braintissue slices resulted in glutamate receptoractivation, as indicated by whole cell electrophysiologicalmeasurements. Photolysis of the otherdesyl amino acids resulted in decomposition and produced severalproducts but did not lead to theformation of furan 2.
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