title: Adenine nucleotide and P-creatine levels in layers of frog retina as a function of dark and light adaptation.
abstract: Eight layers of frog retina were analyzed for ATP, P-creatine, ATP + ADP, and AMP under conditions of dark, 2 sec, 2 min, and in the case of AMP, 2 hr of light adaptation. Samples of each layer, usually ranging between 5 and 50 ng, were dissected from lyophilized frozen sections. After brief light exposure, ATP dropped while ADP rose sharply in the pigment epithelium, outer segments, and inner segments; ADP was too low to be measured accurately in the inner retina. The profile of ATP, P-creatine, and ATP + ADP concentrations showed peaks in the inner nuclear and ganglion layers. AMP, by contrast, was highest in the two plexiform layers. Levels in the inner retina dropped after only 2 sec of light but rose after 2 hr to levels that were higher than dark values in all retinal layers. AMP was often characterized by a non-uniform distribution: adjacent areas of a layer agreed very closely in value to each other but could vary several-fold from a different section of the same frog or from another frog exposed to the same conditions. This distribution produced clusters of values, particularly prominent in dark-adapted animals, something not observed with the other metabolites measured. The peaks of AMP in the plexiform layers suggest that AMP may be a by-product of dopamine-stimulated adenylate cyclase which also has peaks in these same layers.
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003623:Dark Adaptation; D008027:Light; D010725:Phosphocreatine / Q000378:metabolism*; D011894:Rana pipiens; D012160:Retina / Q000378:metabolism*
chemical_list: D000227:Adenine Nucleotides; D010725:Phosphocreatine; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate