title: A comparative study of three methods for intracellular loading of the calcium indicator aequorin in ferret papillary muscles.
abstract: We compared the results of loading the bioluminescent Ca++ indicator aequorin by standard microinjection techniques to those obtained with two new chemical approaches to loading that utilize low concentrations of Ca++ chelator; i.e., 1) Immersion and 2) Macroinjection. After loading with the immersion and macroinjection methods, twitch tension returned to pre-load values indicating lack of damage to the muscles. The aequorin signals obtained with all three methods were similar and converted to similar quantitative values for [Ca++]i. Our data suggest that chemical loading (in particular macroinjection) may be preferable to microinjection, particularly in muscles with increased connective tissue content.
authors.affiliation: Charles A. Dana Research Institute, Boston, MA.
authors.forename: Y
authors.initials: Y
authors.lastname: Kihara
authors.forename: J P
authors.initials: JP
authors.lastname: Morgan
mesh_terms: D000331:Aequorin; D000818:Animals; D001826:Body Fluids / Q000032:analysis*; D002118:Calcium / Q000032:analysis*; D003238:Connective Tissue; D005289:Ferrets; D007202:Indicators and Reagents; D007424:Intracellular Fluid / Q000032:analysis*; D007537:Isometric Contraction; D007700:Kinetics; D008164:Luminescent Proteins; D008297:Male; D008845:Microinjections / Q000379:methods; D008846:Micromanipulation / Q000379:methods; D010210:Papillary Muscles / Q000032:analysis* / Q000502:physiology
chemical_list: D007202:Indicators and Reagents; D008164:Luminescent Proteins; D000331:Aequorin; D002118:Calcium