title: Cyclic nucleotide levels of the photosensitive irises of Bufo marinus and Lophius.
abstract: The sphincter pupillae muscle of several species contracts autonomously after light directly strikes the iris. The response is initiated by isomerization of rhodopsin in the sarcolemma. Light-induced release of CA2+ from internal stores is one step in the transduction process. The levels of cyclic AMP and cyclic GMP were measured after irises were stimulated by light. Stimulation by light does not produce measurable or consistent changes in the levels of either cyclic AMP or cyclic GMP within the photosensitive irises of at least two species, Bufo marinus and Lophius.
mesh_terms: D000818:Animals; D002024:Bufo marinus; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D003623:Dark Adaptation; D005399:Fishes; D007498:Iris / Q000187:drug effects / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008027:Light
chemical_list: D002217:Carbachol; D000242:Cyclic AMP; D006152:Cyclic GMP; D007545:Isoproterenol; D002118:Calcium