Effects of L-proline and some of its analogs on retinal spreading of depression.
L-Proline inhibits glutamate-based spreading depressions (SDs) at low concentrations (2--2.5 mM) and promotes K+-based SDs at higher concentrations (5 mM). The inhibition of glutamate-based SDs was postulated to be due to competition of L-glutamate and L-proline for glutamate receptors on somatic and dendritic plasma membranes. The binding of proline to glutamate receptors was furthermore postulated to result in a release of K+ from the intracellular compartment, enhancing the extracellular K+ concentration sufficiently to promote K+-based SDs. A proline analog, L-baikiain, containing a double bond and one more C atom in the ring structure than proline had similar effects as the latter amino acid, but an analog, L-azetidine-2-carboxylic acid, with one less C atom in the ring had little effect on SD in the retina.
D000818:Animals; D002642:Chick Embryo; D005971:Glutamates / Q000494:pharmacology; D008027:Light; D011188:Potassium / Q000494:pharmacology; D011392:Proline / Q000031:analogs & derivatives* / Q000494:pharmacology*; D012160:Retina / Q000187:drug effects / Q000502:physiology*; D013329:Structure-Activity Relationship
D005971:Glutamates; D011392:Proline; D011188:Potassium