title: Cerium ions in the histochemical demonstration of second-messenger enzymes.
abstract: Second-messenger systems are involved in the regulation of numerous cellular processes. Adenylate cyclase (AC) and guanylate cyclase (GC) enzymes are in key positions in the regulation of these systems. The cerium method has been successfully applied to demonstrate amine- and neuropeptide-stimulated AC in rat nervous and adipose tissues and human sweat glands at the electron microscopic level. AC was also localized in cultured neurons. Nitric oxide compounds stimulated GC were demonstrated in rat hippocampal areas. Enzyme reactions were located in neurons pre- and postsynaptically in synapses; in addition, GC activity was seen intraneuronally and in glial cells. Adipocytes and eccrine glandular cells exhibited reaction products in their plasmalemmas. Optimal histochemical conditions are described, combined with control experiments. Some handicaps, related to the sensitivity of the enzymes to the fixatives, penetration problems of cerium salts, and especially the specificity of the method in phosphatase enzyme histochemistry in general are discussed.
authors.affiliation: Department of Anatomy, Medical School, University of Tampere, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Rechardt
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000032:analysis*; D000273:Adipose Tissue / Q000201:enzymology / Q000648:ultrastructure; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000648:ultrastructure; D002563:Cerium; D002645:Chickens; D002772:Cholera Toxin / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000032:analysis* / Q000037:antagonists & inhibitors; D006651:Histocytochemistry / Q000379:methods*; D006801:Humans; D009457:Neuroglia / Q000166:cytology / Q000201:enzymology / Q000648:ultrastructure; D009474:Neurons / Q000201:enzymology / Q000648:ultrastructure; D009569:Nitric Oxide / Q000494:pharmacology; D051381:Rats; D015290:Second Messenger Systems; D012680:Sensitivity and Specificity; D013545:Sweat Glands / Q000201:enzymology / Q000648:ultrastructure
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D002563:Cerium; D009569:Nitric Oxide; D002772:Cholera Toxin; D000262:Adenylyl Cyclases; D006162:Guanylate Cyclase