On the Brain of Cartilaginous Fishes

This book discusses the correlation between the cerebralization, the astroglial architecture and the blood-brain barrier composition in cartilaginous fishes. Chondrichthyes display a wide range of cerebralization, with the highest brain weight/body weight ratio represented by galeomorph sharks and batoids of the myliobatiform order. The examination was extended to representatives of all these important groups and the book presents the first study on the glial architecture of a Holocephali as well. The present work supplements the former glial impregnation studies; three different astroglial markers - glial fibrillary acidic protein, S-100 protein, and glutamine synthetase - were investigated by immunohistochemical methods, applying both diaminobenzidine and fluorescent techniques. To reveal characteristic features of the blood-brain barrier of cartilaginous fishes the dystroglycan complex and some of its associated proteins were also investigated, as well as aquaporins. The book also highlights evolutionary changes of astroglia in chondrichthyes and discusses the significance of the enlarged brain parts in ecological perspectives.