Observations on the chromaffin granules of the ventricle and the portal vein heart ofMyxine glutinosaL.

Abstract

The chromaffin granules present in the ventricle and the portal vein heart of the hagfish, Myxine glutinosa L., have been studied by electron microscopy, using for fixation a glutaraldehyde method which allows to distinguish between granules carrying either adrenaline or noradrenaline.From sections of fresh tissues as well as from particle fractions prepared by centrifugation of sucrose homogenates of the two hearts, pictures were obtained which confirm the presence of adrenaline in the granule-rich cells in the ventricle and of noradrenaline in the portal vein heart.Attention was also directed to granules, already noted by other observers, that occur in the myocardial cells adjoining the chromaffin cells. It was noted that both in the ventricle and in the portal vein heart these myocardial granules looked moderately electron dense, like adrenaline granules. Possible interpretations of these observations are discussed.

Catecholamines, cardiac natriuretic peptides and chromogranin A: evolution and physiopathology of a ‘whip-brake’ system of the endocrine heart

“…An example is represented by elasmobranchs and Dipnoi, which, for their lack of direct cardiac sympathetic control, depend on the CA-induced modulation of myocardial inotropism and f H (chronotropism) achieved by the activation of cardiac chromaffin cells. (Bloom et al, 1961), (C-E) Helle et al (Helle et al, 1972), (F) Saetersdal et al (Saetersdal et al, 1975) and (G) Helle et al (Helle et al, 1983)]. …”

“…At the same time, within the mammalian atrial myocardium, many studies documented the presence of dense core granules resembling, both morphologically and functionally, those of the endocrine cells (Kisch, 1956;Bompiani et al, 1959;Palade, 1961;Jamieson and Palade, 1964;de Bold and Bencosme, 1973;de Bold, 1979). Soon after these first reports, a number of comparative studies highlighted the evolutionary roots of these granules in cold-blooded vertebrates, demonstrating their presence in atrial and ventricular myocardial cells as well as in the endocardial cells lining the cardiac lumen (Santer and Cobb, 1972;Helle et al, 1972;Helle and Lönning, 1973;Cantin et al, 1979;Helle et al, 1983). An important outcome of these studies was the demonstration of elements of the diffuse neuroendocrine system in the heart of CA-producing cells, mostly corresponding to chromaffin cells.…”