Ragnar Fänge

Plasma cells in adult atlantic hagfish, Myxine glutinosa

SummaryHagfishes, the most primitive vertebrates, are of special interest for the evolution of immune responses. Eptatretus stoutii, the Pacific hagfish, is able to mount cellular and humoral immune responses but all attempts to demonstrate in them the presence of plasma cells have failed. In the present study we demonstrate for the first time plasma cells identifiable by ultrastructural criteria in the pronephros, a primitive lymphohaemopoietic organ, of Myxine glutinosa, the Atlantic hagfish.

THE THYMUS OF THE ANGLER FISH, LOPHIUS PISCATORIUS (PISCES: TELEOSTEI) A LIGHT AND ELECTRON MICROSCOPIC STUDY

Publisher Summary This chapter reviews the thymus of the angler fish, Lophius piscatorius. In most teleosts, the thymus is situated superficially in contact with the epithelium of the branchial cavity and undergoes involution at sexual maturity. However, in the teleost Lophius piscatorius, the angler fish, the thymus is remarkably large and situated remote from the branchial cavity. The thymus of the angler fish is somewhat unique in its size and anatomic position. The thymus of L. piscatorious is seen to be located behind the gills. One of the most interesting cells found in the thymus of Lophius piscatorius are myoid cells, which appeared to undergo a cycle of formation, development, and degeneration in an earlier study described in the chapter.

Choline acetyltransferase activity in the fish swimbladder

Summary1.The activity of choline acetyltransferase (ChAT) has been determined in different parts of the swimbladder of two physostome species, the rainbow trout,Salmo gairdneri, and the eel,Anguilla anguilla, and three physoclist species, the Atlantic cod,Gadus morhua, the perch,Perca fluviatilis and the goldsinny wrasse,Ctenolabrus rupestris.2.High activities of ChAT were found in the gas gland of the physoclist species. Preganglionic denervation (in the cod) only partly reduces this activity. It is concluded that the gas gland has a postganglionic cholinergic innervation.3.The secretory mucosa outside the gas gland shows intermediate ChAT activity in the wrasse and low activity in the cod and the perch.4.Very low activities of ChAT were found in the oval edge of the cod and the perch, indicating little if any cholinergic innervation of this area. The resorbent area of the wrasse swimbladder shows an intermediate activity.5.In the eel the secretory mucosa shows low ChAT activity, indicating sparse innervation of the secretory cells. The resorbent mucosa contains a much higher activity.6.The rainbow trout has an evenly distributed intermediate ChAT activity in the swimbladder.