Adrenergic Nerve Fibers Research Articles

Investigation of the taste buds of the frog tongue by luminescence microscopy

Special dumbbell-shaped cells of unknown nature, rich in catecholamines and giving a specific yellowish-green luminescence, were found inside the taste buds. The taste buds responded differently to preliminary (24 h before taking the material) injection of reserpine (0.25 mg). In some taste buds the dumbbell cells lost their property of specific luminescence and became invisible. In othertaste buds the intensity of luminescence of the cells, especially of their outer thickenings, was sharply reduced. Adrenergic nerve fibers, giving green luminescence, were found in the lingual epithelium of the tongue as bundles and single varicose axons, winding around the blood vessels entering the taste buds as well as other blood vessels. The epithelial tissue of the tongue was richly innervated with adrenergic fibers.

Sympathetic innervation of the normal human thyroid.

The sympathetic innervation of the normal human thyroid was investigated by a combination of fluorescence histochemistry and electron microscopic autoradiography. Sympathetic, adrenergic nerve fibers were numerous in the human thyroid, and they were mainly found in two locations: in relation to vessels, and in interfollicular spaces. The terminals of the vascular nerves were located very close to smooth muscle cells in the vessel wall, and the interfollicular nerve terminals had a similarly close relation to follicle cells; only the respective basement membranes intervened. It is concluded that, in man, there is a morphological basis for an influence of the sympathetic nervous system not only on thyroid vessels but also directly on thyroid follicle cells.

Qualitative and quantitative studies on the innervation of the corpus luteum of rat and pig

Qualitative and quantitative studies were made to determine the amount of nerve fiber supplying corpora lutea (CL) of rats during the oestrous cycle and pregnancy and sow CL during days 4–6 after ovulation. Fluorescence microscopy of freeze-dried, paraformaldehyde treated (Falck-Hillarp method) rat ovaries reveals adrenergic nerve fibers which run along with vessels and form a network among interstitial gland cells. Nerve fibers do not enter the granulosa cell layer in follicles or CL. In the CL circumference both vascular and non-vascular nerves occur the latter being related to the fibromuscular layer and probably innervating smooth muscle cells. No striking differences exist between the innervation of the ovary in non-pregnant and pregnant rats. Bodian and methylene blue staining did not contribute to a more detailed knowledge of rat ovary nerve supply. Electron microscopic quantitative analysis of rat and pig CL (rat: day 18 of pregnancy; pig: day 4–6 after ovulation) revealed no axon profiles in 2.000 grid squares (one square measuring 2.25×10-2 mm2) of randomly taken CL sections. Thus it was possible to calculate an upper limit of 133 μm of nerve fibers per 1 mm3 CL tissue, in case there were any at all.

Adrenergic innervation and vascular patterns in caine adipose tissue

To visualize blood vessels, canine adipose tissue (in subcutis, mesentery, and omentum) was perfused with a silicone elastomer containing a fluorescent material, Rhodamine B. Adrenergic nerve fibres were made fluorescent by formaldehyde treatment of stretch preparations by the method of Falck and Hillarp. An extensive capillary network surrounding each adipocyte was found. In the mesentery the adipocytes appear to be located in the venous section of the microvasculature rather than on the arterial side. This indicates that adipocytes are localized to vessels with the highest permeability. A rich perivascular plexus of fluorescent varicose nerves could be seen around the arteries and veins. Nerve fibres could also be found between adipocytes. However, the pattern of distribution was not as regular as that of the microvasculature. In some areas no adrenergic nerve fibres could be identified around the adipocytes. This might indicate that there are two pools of adipocytes in a tissue, one which is innervated by adrenergic fibres and responds with increased lipolysis to sympathetic nerve activity and another which does not.

Sympathetic innervation of the mouse thyroid and its significance in thyroid hormone secretion.

Studies were performed in mice to investigate the sympathetic innervation of the thyroid and to evaluate its role in the regulation of thyroid hormone secretion. Fluorescence histochemistry and electron microscopic autoradiography were used to study the distribution of adrenergic fibers and terminals in the thyroid and their relation to follicle cells and vessels. Bilateral surgical sympathectomy was performed by extirpation of the superior cervical ganglia, and pharmacological sympathectomy by iv injections of 6-hydroxydopamine. The secretion of thyroid hormone was estimated by daily measurements of the blood radioiodine (BRI) levels. Sympathetic, adrenergic nerve fibers were numerous in the mouse thyroid, and were mainly found in 2 locations: in relation to arterioles, and in interfollicular spaces. The terminals of the latter group had a very close relation to follicles and often were in direct contact with them, only the follicular basement membrane separating the adrenergic terminal and the follicle cell. In addition, interfollicular terminals often had a close relation to capillaries. It is concluded that in mice there is a morphological basis for a direct, nonvascular influence of the sympathetic nervous system on thyroid follicle cells. In addition, sympathetic stimuli may influence thyroid blood flow by effects on both arterioles and capillaries. Both pharmacological and surgical sympathectomy elicited a reduction in BRI levels that persisted for 1 or 2 days, presumably as a reflection of decreased thyroid hormone secretion. In view of this finding, and since a previous study has shown that unilateral sympathetic stimulation causes a large increase in BRI levels, preceded by formation of colloid droplets in the portions of the thyroid supplied by the stimulated nerve, it is suggested that the sympathetic innervation of the thyroid serves as a means for effecting prompt, short-term alterations in the rate of thyroid hormone secretion. (Endocrinology94: 959, 1974)

Role of sympathetic fibres and of adrenal medulla in the maintenance of cardio-vascular homeostasis in normotensive and hypertensive rats

The Concept of modulation of cardiovascular system by the autonomie nervous system has been accepted for a long time. However, the efferent sympatheticcomponent of the autonomie nervous system is more dynamically related to the peripheral cardiovascular system by a dense plexus of excitatory fibres distributed to the heart and to all vascular beds. Small arterioles which are crucial to the homeostasis of arterial blood pressure were found to be the most densely innervated segments of the vascular tree (N orberg, 1967). In addition to this network of excitatory fibres, the sympathetic nervous system is also responsible for the control of catecholamine secretion by the adrenal medulla which can also influence the heart and blood vessels by acting on specific receptors to catecholamines localized in these structures. Little is known about the relative contribution of each component of the sympathetic system in the maintenance of normal cardiovascular functions. In numerous previous studies, the effects of sympathectomy were studied after surgical denervation, after treatment with nerve growth factor antiserum or after administration of catecholamine depleting drugs such as reserpine. Most of these techniques however were either non specific to the peripheral fibres or, resulted in an incomplete sympathectomy so that the conclusions reached with these procedures may be questionable. The discovery that 6-hydroxydopamine (6-OH-DA) could specifically and selectively destroy adrenergic nerve fibres (T ranzer and Thoenen, 1967) has given a more specific and more useful tool for the study of the role of the sympathetic nervous fibres. In periphery, 6-OH-DA when given in sufficient amount, causes the degeneration of the great majority of sympathetic fibres without destroying the ganglion cell bodies or the adrenal medulla.

Hydrocortisone-induced increase in the histochemically demonstrable catecholamine content of sympathetic neurons of the newborn rat

Newborn rats were subcutaneously injected with 20 mg/kg body weight of hydrocortisone acetate each day for 5 days and were killed together with untreated controls 5 h or 10 days after the last injection. Histochemically demonstrable formaldehyde-induced fluoescence was studied in freeze-dried superior cervical ganglia and in strech preparations of the intestine and the aris. Fluorescence intensity was measured by visual estimation and microcope photometry. Hydrocortisone treatment caused a statiscally significant increase in the number of intensely fluorescent nerve cell bodies and a corresponding decrease in the number of moderately fluorescent nerve cell bodies in the superior cervical ganglia. In the Auerbach's plexus of hydrocortisone-treated rats all fluorescent fibers were more clearly delineated, showed more often varicosites and exhibited o more intense fluorescence, as compared with those of the control rats. The network of adrenergic nerve fibers in the iris showed, likewise, significant increase in the fluorescence fiber treatment with hydrocortisone. The increased nerve fiber fluorescence was observed also 10 days after the last hydrocortisone injection. It is concluded that hydrocortisone causes an increase in the content of noradrenaline in the sympathetic neurons, probably by increased synthesis.

Adrenergic innervation of brown adipose tissue from the ground squirrel (Citellus richardsonii).

Determinations of noradrenaline (NA) content and observations of histochemical fluorescence were carried out on the axillary brown fat pad of ground squirrels Citellus richardsonii kept at two temperatures, 20 °C and 5 °C. For comparison, NA content of hearts and intrathoracic brown adipose tissue were also determined. Like interscapular brown adipose tissue from cold-acclimated rats, the axillary brown fat of cold-acclimated ground squirrels contained a high level of NA. The NA content of the fat pad from ground squirrels living at 20 °C, however, though somewhat lower was not statistically different from that of the fat pad from the cold-acclimated animals. Fine adrenergic nerve fibers were observed between the adipocytes and more intense and extensive networks were present around arterioles. The density of adrenergic innervation appeared similar in the axillary brown fat of the two groups. The NA content of the hearts of ground squirrels living at 5 °C was lower than that for hearts from animals at 20 °C. Intrathoracic brown fat tissue from both groups of animals showed large variation.

Adrenergic innervation in the rabbit cochlea.

The distribution of adrenergic nerve fibres in the rabbit cochlea was investigated with fluorescence and electron microscopic techniques. Interest was focused on the habenula region. After administration of a false transmitter the fine structure of adrenergic nerve fibres and their relationship to other structures were studied. A multitude of adrenergic nerve terminals were found around radiating nerve fibres where they lose their myelin sheaths. Apart from this nerve fibre innervation there was an extensive innervation of the spiral vessel of the tympanic lip, under the inner hair cell. This blood vessel was of capillary size and lacked contractile elements. No adrenergic innervation was observed in the organ of Corti or in the stria vascularis. The cochlear adrenergic innervation was found to have its origin in the ipsilateral superior cervical ganglion. Possible ways of adrenergic influence on sound perception was discussed.

Effect of hydrocortisone on the extra-adrenal intensely fluorescent chromaffin and non-chromaffin cells in stretch preparations of the newborn rat.

Air-dried stretch preparations were used to study adrenergic nerve fibres and catecholamine-containing cells with the formaldehyde-induced fluorescence method in the abdominal tissue block containing the para-aortic paraganglia, in the neurovascular structures of the cervical region including the carotid body, in the bladder, in the ileum, in the mesentery, in the vagus nerve and in the sympathetic ganglia of 5- or 15-day-old rats. The adrenergic nerves and the catecholamine-containing cells were well preserved and showed little or no diffusion of amines. While most intensely fluorescent cells of the main para-aortic body disappeared during the first two postnatal weeks, some such cells survived and they showed long, slender fluorescent processes. Administration of 20 mg/kg of hydrocortisone acetate daily for 5 days after birth caused a striking increase in the number and size of the clusters of the intensely fluorescent cells in the organ of Zuckerkandl, in the sympathetic ganglia and in the bladder, as well as an increase in the fluorescence intensity of the carotid body. In rats treated with hydrocortisone for 5 days and left to recover for 10 days an increased fluorescence was still observed. However, in the organ of Zuckerkandl the intensely fluorescent cells of hydrocortisone-treated 15-day-old rats showed less processes than those of the control rats of the same age.

The atrioventricular valves of the guinea-pig. I. A light microscopic study.

AbstractThe atrioventricular valves contain dense plexuses of adrenergic nerve fibers, derived from atrial and ventricular sources. Most of the adrenergic terminals are located in the lower third of the cusps. This region, which contains adrenergic terminals and acetylcholinesterase‐positive nerve endings is devoid of muscle fibers and blood vessels. The acetylcholinesterase‐positive endings may be sensory; and norepinephrine released from the adrenergic terminals may influence their performance. In the mitral valve, the atrial adrenergic plexus is separated from the ventricular plexus by a narrow zone that is free of adrenergic nerves. In most other respects the innervation, musculature and vascular supply of the mitral valve is similar to that of the tricuspid valve.Each valve has an intrinsic skeleton. This is made up of collagenous “ribs” that pass up from the chordae tendineae and fan out in the cusps. “Ribs” from adjacent chordae overlap and interweave, forming a complex support system.The musculature of the valves is complex and seems to have several functions. The annular muscle around the valve orifice may act as an atrioventricular sphincter, while offshoots that insert into the collagenous “ribs” of the cusp may assist the papillary muscles in maintaining tension on the cusps. The meshwork of muscle fibers between “ribs” may prevent ballooning of the cusps during systole. We found no consistent association between valvar muscles and nerves. Blood vessels are restricted mainly to the upper muscular part of the cusps, although a few capillary loops descend into the midzone of the cusps.

Regulation of catecholamine release. The muscarinic inhibitory mechanism

Publisher Summary This chapter discusses the muscarinic inhibitory mechanism for regulation of catecholamine release. The elucidation of a muscarinic mechanism which inhibits the release of noradrenaline (NA) from peripheral adrenergic nerve fibers started from the observation, on the perfused rabbit heart, that atropine greatly enhanced the noradrenaline output produced by infusion of acetylcholine. Muscarinic inhibition probably affects a process which in the sequence of events leading to release of transmitter occurs after excitation of nicotinic receptors. Blockade of nicotinic receptors with hexamethonium does not prevent the acetylcholineinduced inhibition of noradrenaline output evoked by sympathetic nerve stimulation. The catecholamine releasing procedures susceptible to muscarinic inhibition are invariably dependent on the presence of extracellular calcium ions. This has been demonstrated for noradrenaline release by sympathetic nerve stimulation, nicotinic drugs and high potassium. On the other hand, tyramine-induced noradrenaline release which does not require calcium is not decreased by methacholine. The correlation between calcium-dependency of transmitter release and presence of muscarinic inhibition was confirmed by studies utilizing a false transmitter amine.

Intramural distribution of adrenergic and cholinergic nerve fibers innervating arterioles of the hamster cheek pouch.

AbstractElectron microscopic, autoradiographic and histochemical techniques were used to determine the distribution of adrenergic and cholinergic nerve fibers within the walls of arterioles having a width of 35 to 60 μ in the hamster cheek pouch. Nerves were confined to the adventitia and their varicose regions were distributed so that 86% were located within 1 μ of the media. Arterioles exposed to 3H‐norepinephrine and examined by light microscopic autoradiography exhibited several sites of silver grain accumulation, as a result of the uptake of 3H‐norepinephrine by adrenergic nerve fibers. In electron autoradiographs, approximately 70% of all adventitial nerve fibers exhibited silver grains and are therefore considered to be noradrenergic. The majority of all nerve‐associated silver grains were located near the adventitial‐medial junction. Smooth muscle cells sometimes possessed concentrations of silver grains above background levels, perhaps reflecting the capacity of these cells to take up norepinephrine. Acetylcholinesterase activity was demonstrated in 16 to 44% of the adventitial nerve fibers and they are presumed to be cholinergic. Acetylcholinesterase‐stained fibers were distributed throughout the adventitia with 43% being located closer than 1 μ to the media. The morphological identification of a dual adrenergic and cholinergic innervation of arterioles of the hamster cheek pouch indicates the probable presence of an active as opposed to a passive vasodilatory mechanism.

Electron microscopic and histochemical studies on the synaptic vesicles in mouse vas deferens and atrium after 5-hydroxydopamine administration.

AbstractAfter administration of 5‐hydroxydopamine, one of the “false” adrenergic transmitters, core materials within both large and small vesicles of the adrenergic nerves increase in density, while clear vesicles in the cholinergic nerves do not change. In the vas deferens of the mouse, initial sign of the uptake is seen as early as one minute after intravenous administration. Eighty to ninety percent of vesicles in the adrenergic nerve varicosities are filled with dense cores by more than 100 mg/kg of 5‐OH‐DA administration. 5‐OH‐DA stored in the vesicles remains for seven to ten days and gradually disappears thereafter. After administration of 5‐OH‐DA, acetylcholinesterase (AChE) activity is examined in the nerve varicosities in the atrium. AChE activity in the adrenergic nerve fibers is discussed in the light of these findings.

Effect of Acetylcholine on Isolated Cat and Rabbit Heart Ventricle Preparation

Abstract: The atria and the upper part of the intra‐ventricular septum were removed from rabbit and cat heart, and the ventricular preparations were perfused in vitro with Krebs's solution. Preparations from twenty cats and 15 rabbits were studied for their sensitivity to acetylcholine. In the isolated rabbit ventricular preparations, acetylcholine in doses of 0.01‐0.1 pg caused a very weak negative inotropic and a chronotropic effect. Higher doses caused a dose‐dependent standstill. The cat ventricle preparations were rather insensitive to acetylcholine. When studied against noradrenaline induced increases in heart rate and force of contraction, acetylcholine in these preparations, also, caused a negative inotropic and chronotropic effect. In both the cat and rabbit preparations, the effect of acetylcholine was blocked by atropine 0.1 μg/ml in the perfusing solution. After pretreatment with atropine, acetylcholine (50‐100 μg) caused a positive inotropic and chronotropic effect that was blocked with propranolol 0.1‐0.2 μg/ml. This effect of acetylcholine was not obtained in preparations from reserpine treated animals.It was concluded that the cat and rabbit ventricle myocardium contains receptors to acetylcholine, and that stimulation of these cause a negative inotropic and chronotropic effect. Moreover, acetylcholine may release noradrenaline from the adrenergic nerve fibres. The difference in sensitivity to acetylcholine between the two species may indicate a difference in the significance of parasympathetic nerve stimulation to the ventricular myocardium in the two species.

Histochemically demonstrable catecholamines and cholinesterases of the rat uterus during estrus cycle, pregnancy and after estrogen treatment.

AbstractThe changes of the adrenergic and cholinergic nerves of the rat uterus were examined during the estrous cycle, pregnancy and after estrogen treatment. During the first 2 weeks of pregnancy and after estrogen treatment the fluorescence intensity and the thickness of the extra‐vascular adrenergic nerve fibres increased, but decreased in the end of pregnancy. The activity and also the density of AChE‐positive nerves increased after estrogen treatment and during the first 2 weeks of pregnancy and decreased at the end of pregnancy. The AChE‐activity and the intensity of fluorescence in the nerves was somewhat stronger in estrus than diestrus.

Distribution and origin of adrenergic nerve fibers in the vestibular apparatus and their arterial supply in the guinea pig. A fluorescent microscopic study.

Fine adrenergic nerve fibers which are distributed to the saccular and utricular maculae, ampullar capsules and ducts of the semicircular canals and vestibular nerve of the guinea pig were observed by fluorescent microscopy. These fibers were divided into three groups according to their course and location: perivascular, nerve trunk, and independent groups. The arteries leading to the vestibular organs contained many adrenergic fibers. The uni- and bilateral cervical sympathetic denervations at various levels showed that the adrenergic fibers in the vestibular organs originated in the ipsilateral superior cervical ganglion. Regarding the arteries leading to the vestibular organs, the basilar, anterior inferior cere-bellar, labyrinthine and common cochlear arteries receive adrenergic fibers from the bilateral superior cervical ganglia, while the peripheral branches of the labyrinthine artery receive their adrenergic fibers only from the ipsilateral superior cervical ganglion. These adrenergic fibers come f...

Distribution of Adrenergic and Cholinergic Nerve Cells and Fibers in the Bursa of Fabricius of Chicken

Distribution of Adrenergic and Cholinergic Nerve Cells and Fibers in the Bursa of Fabricius of Chicken

Nervous control of intestinal motility in gold fish (author's transl)

The mechanical activities and innervation of the intestinal bulb of the gold fish were investigated by pharmacological and histochemical techniques.The mechanical responses of the intestinal bulb to the transmural stimulation could be classified into three different components; (1) initial rapid contraction, (2) relaxation, (3) late slow contraction. The initial rapid contraction was inhibited by dTc or by tetrodotoxin (TTX). The relaxation was inhibited by TTX but not inhibited by guanethidine. Thelate slow contraction was slightly depressed by atropine. This atropine resistant contraction in late slow phase was completely inhibited by TTX.DMPP was effective to produce the initial rapid and late slow contractions which are similar to the response of transmural stimulation.The biphasic contraction, which caused by DMPP was reversed to initial relaxation and late slow contraction after the application of atropine and dTc. These relaxation and late slow contraction were inhibited by C6 or TTX.These results may suggest the presence of two types of excitatory neurogenic responses in thistissue.Histochemical observations revealed the presence of adrenergic nerve fibers within the musculature of the intestinal bulb.

A stimulatory effect by nerve growth factor on the regrowth of adrenergic nerve fibres in the mouse peripheral tissues after chemical sympathectomy with 6-hydroxydopamine

Systemically administered Nerve Growth Factor (NGF) had a strong stimulating effect on the regeneration of fully developed adrenergic neurons in the peripheral tissues of the mouse after axotomy induced by 6-hydroxydopamine. The NGF stimulation was investigated at 9 and 21 days after the 6-hydroxydopamine injection, and was observed fluorescence histochemically as an increase in number, length, and thickness of the outgrowing adrenergic fibre bundles, in the extent and abundance of the terminal ramifications of the regrowing fibres, and in their fluorescence intensity. This increase in the regrowth of the lesioned adrenergic axons was paralleled by strong and significant increases in the recovery of endogenous noradrenaline in several peripheral tissues. The present findings demonstrate a sensitivity of fully developed adrenergic neurons to NGF during axonal regeneration, and it is suggested that NGF might play a normal physiological role in this process.