[Quantitative analysis of the structure of the varicose dilatations in the nerve fibers of the rabbit coronary artery (according to the results of three-dimensional reconstruction)].

Axoplasmic vesicles and microtubes in varicosities of axonal plexus in the external sheath of the rabbit coronary artery have been studied. Comparing serial sections and examining three-dimensional reconstruction of small nerve plexus, it was demonstrated that various varicosities differed only in their correlation of the amount of small (30-80 nm) and large (80-180 nm) vesicles. Average diameters in profiles of small and large vesicles are 56.3 nm and 115.6 nm, respectively. There are varicosities containing about 250 or more than 1,000 vesicles. Evenly distributed vesicles throughout the volume of varicosities and lack of specialized structures on the axolemma are supposed to demonstrate the absence of special areas for the mediator removal in the axons studied. The microtubes in the varicosities are peripherally arranged, next to the axolemma and form 1-1.5 wide coils. A suggestion is made that the varicosities in neighbouring axons of the same nerve plexus, with specific structural organization, are special functional units and appear to be peculiar not only for nerve plexus of the coronary artery, but also for other parts of the peripheral vegetative nerve system.