Biomedical subjects
Publications and source records attributed to S Dolezel.
It is well-known that the ligation of nerve trunk induces an intensive accumulation of noradrenaline proximally to the ligation. A similar ligation, performed in the sympathetic ground-plexus, induces no changes in the segments of terminal fibres situated proximally.
The monoaminergic innervation of the coronary vessels and myocardium in the dog was studied by means of the histochemical fluorescence method. The distribution of monoaminergic terminals in the arterial wall depends on the diameter of the artery. In large arteries, the terminals are regularly distributed around the entire circumference, the fibres being situated between the elastic lamellae of the adventitia. The terminals within the media could not be detected. In small arteries, the sympathetic ground plexus aggregates in two parallel strands, the artery being between them. In arterioles, two thick fibres only accompany the vellel. The myocardium is innervated by means of a three-dimensional sympathetic ground plexus distributed between the myocardial cells independently of vessels. No difference in density of innervation was found between the right and left heart. The point-counting method, on the other hand, has revealed that the density of innervation in the left auricle is nearly twice as dense as in the left ventricle. The terminals innervating the myocardium are markedly thinner than the fibres innervating the arteries. Two-dimensional plexuses innervate the epicardium, endocardium and valves.
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Experiments on rats demonstrated that one month after the reduction of pressure in the vessels of the hind part of the body caused by narrowing of the abdominal aorta lumen the number of functioning capillaries in the gastrocnemius and the soleus muscles was practically the same as in control animals. These results allowed the authors to assume that a decrease of the hydraulic resistance of the resistive vessels in the area of chronic local arterial hypotension was not connected with an increase in the number of parallelly functioning vessels.
The adrenergic innervation of the juxtaglomerular complex was studied in kidneys from mice, rats, guinea-pigs, rabbits, cats, dogs, pigs, monkeys, and humans using fluorescence histochemistry of neuronal noradrenaline and autoradiography of 3H-noradrenaline. The localization of the nerves was established by phase contrast optics or by perfusing the vascular system with India ink. Adrenergic nerve terminals, exhibiting a formaldehyde-induced fluorescence and having the ability to take up and accumulate 3H-noradrenaline, were easily identified when they enclosed the glomerular afferent arteriole. They continued in between and close to the macula densa and lacis cells to supply the glomerular efferent arteriole. The nerves could be seen to accompany this arteriole for a considerable distance until they branched off to the vasa recta in the juxtamedullary region and to adjacent cortical veins. This innervation pattern was found to be a constant feature except in kidneys from guinea-pigs and cats, in which post-glomerular units. The fluorescence in all adrenergic fibres supplying the juxtaglomerular complex disappeared after removal of the aortico-renal ganglion, showing that they belong to a common system of renal sympathetic nerves.
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The disposition of sympathetic transmitter within the wall of rat femoral and rabbit saphenous arteries has been studied during sympathetic stimulation. Using a histochemical fluorescence technique, sharply delineated bead-like fluorescent spots representing sympathetic nerve terminals were found at the adventitio-medial junction. In specimens excised during sympathetic nerve stimulation, the entire media was veiled by fluorescent material representing noradrenaline which had diffused into that layer after release. The localization of the nerve terminals in controls as well as diffusion of transmitter during stimulation in the rat femoral artery was corroborated by autoradiography of tritiated noradrenaline.
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A special reticular basket-like system of connective tissue strips (called connective tissue skeleton - CTS) was found between the cortex and medulla in the kidney of various mammals. It enlarges the wall of the renal calyx (or pelvis) into the parenchyma. The main component of this system is collagen. A small amount of smooth muscle cells was found in one part of CTS srips situated around the papilla (the levator fornicis muscle). A dense monoaminergic and scanty cholinergic innervation was found in the whole system of the CTS. The functional importance of this system is discussed: (i) a tightly linked connection between the urine-discharging system and the kidney, (ii) 'milking' and similar effects in the papilla as well as perception of intrapelvic and intrarenal pressure, (iii) penetration of infection into the kidney and (iv) liberation of the monoaminergic transmitter.
The coagulation of the sensitive part of the Gasserian ganglion in rabbits did not cause the disappearance of acetylcholinesterase-positive nerve fibres in the corneal epithelium. Most of them were very well detectable 6 to 8 days after operation. The autors cannot exclude the possibility that the interval between the coagulation and the killing the animals could be too short for disappearance of acetylcholinesterase reaction, but they express the view, that another source of corneal innervation by cholinesterase positive nerve fibres is to be taken into consideration.
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