title: Observations on cardiac ultrastructure of the adult Japanese newt, Cynops pyrrhogaster.
abstract: Investigation of atrial and ventricular cardiac ultrastructure by transmission and scanning electron microscopy of the adult Japanese newt, Cynops pyrrhogaster, has revealed some unique cell types and features in this amphibian. Typical urodelan-type thin trabeculae composed of myocytes with conventional architecture of loosely scattered myofibrils were observed. Scarce granules of variable size and density were seen in atrial myocytes, and some Purkinje-like fibers were observed. Unique structures included scattered endocrine-like cells with dense cytoplasmic granules in the epicardial spaces, a distinct granular cell found occasionally on the endocardial surface projecting into the lumen of the cardiac trabeculae, and peculiar granulated inclusions in the myoplasm. The function of these possible endocrine cells remains undetermined. It is important to characterize the heart of this species, as it has recently been proven to be an excellent model for prolonged experimental studies in vitro.
authors.affiliation: Department of Biomedical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg.
authors.forename: C J
authors.initials: CJ
authors.lastname: Pfeiffer
authors.forename: M
authors.initials: M
authors.lastname: Asashima
authors.forename: C H
authors.initials: CH
authors.lastname: Cho
authors.forename: K
authors.initials: K
authors.lastname: Shimada
mesh_terms: D000818:Animals; D004699:Endocardium / Q000648:ultrastructure; D005260:Female; D006329:Heart Conduction System / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009206:Myocardium / Q000648:ultrastructure*; D012455:Salamandridae / Q000033:anatomy & histology*