Premium
ULTRASTRUCTURE OF VASCULAR ENDOTHELIUM IN THE FROG
Author(s) -
Stehbens W. E.
Publication year - 1965
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1965.sp001804
Subject(s) - vesicle , basement membrane , endothelium , ultrastructure , cytoplasm , anatomy , biology , electron microscope , vesicular transport protein , biophysics , lumen (anatomy) , cell junction , microbiology and biotechnology , chemistry , membrane , cell , biochemistry , physics , optics , endocrinology
An electron microscopic investigation of the endothelium of capillaries and venules of the frog ( Hyla cœrulea ) revealed, as well as the usual cytoplasmic constituents, several new features. In the endothelial cells three types of vesicle were encountered, each of which could be highly selective in the transport of materials across the vessel wall. The well‐recognized micropinocytotic vesicles of light density were most numerous. Less frequently seen, and hitherto unobserved in endothelium, were the dense‐walled micropinocytotic vesicles which at other sites are associated with protein uptake. Large vesicular spaces similar to the macropinocytotic vesicles described by Fawcett [1963] were readily observed. Fenestrated endothelium occurred in attenuated segments of endothelial cells in the tongue as well as in the gut. Fenestrae were seen in the walls of macropinocytotic vesicles and along the cytoplasmic processes projecting into the lumen or along those which overlapped adjacent cells. At intercellular clefts, tight junctions predominated. Occasional intermediate junctions were found but no desmosomes. Thick basement membranes, the result of the coalescence of a thin endothelial basement membrane and thick convoluted laminae related to pericytes and adventitial cells, were found about vessels particularly in the tongue. Microtubules and microtubular bodies of unknown significance were observed.