Myoendothelial Relations in the Conduit Coronary Artery of the Dog and Rabbit

Abstract

This paper describes the myoendothelial relations in ramus interventricularis anterior and its branches in the dog and rabbit. Endothelial cells (ECs) are separated from smooth muscle cells (SMs) by fenestrated internal elastic lamina (IEL). The number of fenestrations increases towards the periphery; the first- and second-order branches have only patches of elastin in some places. ECs and SMs emit protrusions of various shapes into the fenestrae. The distance between EC and SM protrusions varies. Close appositions were also found. The diffusion of autacoids, or transmitters, as well as the electrical and biochemical mechanism of transmission seem to be involved in the transfer of information from ECs to SMs and vice versa. Biomechanical transfer (for example shear stress), via EC-SM junctions is also considered.