Adrenergic Nerve Fibers Research Articles

Histochemical demonstration of adrenergic nerve fibres and serotonin-containing mast cells of the knee joint synovial membrane in rats.

Distribution of noradrenergic nerves and serotonin-containing mast cells in the synovial membrane of rat knee joints was demonstrated using the histochemical fluorescence technique of Falck-Hillarp.

The innervation of the cutaneous artery in the toad Bufo marinus

1. 1. The autonomic innervation of the cutaneous artery of a toad ( Bufo marinus) was investigated by techniques of vascular perfusion and by the fluorescence histochemical technique for the demonstration of adrenergic neurons. 2. 2. The cutaneous artery was innervated by excitatory adrenergic nerve fibres originating in the cervical sympathetic connective and running in the pulmonary vago-sympathetic supply. The initial segment of the cutaneous artery was circumscribed by a moderately-dense plexus of catecholamine-containing fibres lying at the outer border of the tunica media. 3. 3. In jointly-perfused pulmonary and cutaneous artery preparations, injected acetylcholine, which caused a marked pulmonary arterial constriction, caused an increase in the proportion of total flow leaving via the initial segment of the cutaneous artery. 4. 4. It was concluded that, since the pulmonary and cutaneous arteries in the toad are to some extent reciprocally innervated, the toad has the capacity to selectively perfuse either the lungs or the skin.

Postnatal ontogenic development of the adrenergic innervation pattern in the rat portal vein. A histochemical study.

The postnatal development of the adrenergic innervation pattern in the rat portal vein has been studied with the histochemical fluorescence method of Hillarp and Falck. Stretch preparations and transverse freeze-dried sections of intact portal veins were studied from rats during the first 5 weeks of life and from adult rats. Orientation of undifferentiated smooth muscle cells into two layers was observed at 4 days of age. Dominance of the thick outer longitudinal muscle layer was apparent at two weeks of age. A terminal adrenergic nerve plexus with some varicosities was restricted outside the media at the end of the first week. Ingrowth of penetrating non-terminal adrenergic nerve fibers through the longitudinal muscle layer occurred during the second week of age when the main terminal nerve plexus was developing between the two muscle layers. After 3 weeks of age the adult pattern of a two-dimensional adrenergic plexus between the muscle was established. In the adult rat pharmacological treatment with nialamide and noradrenaline revealed the thin, penetrating non-terminal adrenergic nerve fibers in the longitudinal muscle layer which were poorly visible otherwise. The present observations strongly indicate that the main adrenergic plexus between the two muscle layers emanates directly from the outer axonal plexus. These findings are discussed regarding possible trophic interactions between ingrowing sympathetic adrenergic vasomotor nerves and maturing vascular smooth muscle.

Catecholamine-Containing Nerve Fibres in the Human Abdominal Vagus

The vagal nerve of man has been investigated for the presence of adrenergic nerve fibres using the histochemical fluorescence method of Hillarp and Falck. Following 30-60 min of nerve ligation during surgical operations, the right anterior main trunk (subdiafragmatic level) from one patient, and the anterior nerve of Latarget of 5 patients were found to contain unmyelinated nerve fibres with accumulations of green fluorescent material representing a catecholamine. The observations indicate the presence of adrenergic nerve fibres running caudally in the human vagal nerve, in accordance with similar findings in other mammals, e.g. cats and dogs.

The Mechanoreceptors of the Sinus Hair Organ on the Cat's Foreleg

The follicles of the cat's carpal sinus hairs are supplied by free nerve endings and Merkel cell-neurite complexes. Simple lamellated corpuscles lie within the cavernous blood sinus. Slowly adapting sinus hair follicle units showed a directional sensitivity and responded to mechanical stimulation with a high-frequency velocity-dependent dynamic impulse discharge and an amplitude-dependent static response. A few sinus hair follicle mechanoreceptors were of fast adapting type. Pacinian corpuscles located close to the external sinus walls responded to vibratory stimuli. Hair disks immediately lateral to each sinus hair gave slowly adapting discharges. The functional significance of the unique combination of four mechanoreceptor types with different response properties within the carpal sinus hair organ is emphasized. Adrenergic nerve fibers are evaluated within cat sinus hair follicles. Electrical stimulation of the cervical sympathetic trunk produced small but repeatable changes in the dynamic responses of slowly adapting mechanoreceptors of cat vibrissae follicles.

An electron microscopic study on the innervation in the taste buds of the mouse circumvallate papillae.

Taste buds of the mouse circumvallate papillae were studied by electron microscopy to elucidate the innervation involving the adrenergic nerve supply. Typical afferent synaptic contacts, with increased density of the membranes and aggregations of synaptic vesicles in the cytoplasm adjacent to the nerve endings, were demonstrated between the type III cells and the nerve endings. Along the regions of contact between the type II cells and the nerve endings, cisternae of endoplasmic reticulum were often seen beneath the cell membrane, and the nerve endings contained relatively many synaptic-sized vesicles. Such an innervation seems to be efferent in nature. For the detection of the adrenergic nerve supply, 5-hydroxydopamine (5-OH-DA) was injected after pretreatment with L-DOPA and nialamide. The mice showed numerous adrenergic nerve fibers in the connective tissue underlying the taste buds. On very few occasions, the adrenergic nerves penetrated the basal lamina of the taste buds and came into contact with the bud cells. Some adrenergic nerves were distributed among the epithelial cells around the taste buds. The reaction product from acetylcholine esterase activity was found around the adrenergic nerve fibers labeled with 5-OH-DA.

Pharmacologic analysis of papaverine-induced positive chronotropic and intropic effects

Effects of papaverine in sinus rate and atrial contractility were investigated using the isolated atrium preparation of the dog perfused with heparinized arterial blood led from a support dog. When papaverine was injected into the cannulated sinus node artery, positive chronotropic and inotropic reponses were dose-relatedly produced from about 3 μg. At a dose level above 100 μg, papaverine induced initially slightly negative chronotropic and inotropic effects followed by marked positive ones. Paparevine-induced positive chronotropic and inotropic effects (P-PCIE) were not influenced by treatment with tetrodotoxin which blocked the action of nicotine. P-PCIE were slightly suppressed by an adrenergic ß-blocking agent, alprenolol, which blocked the action of norepinephrine. They were however potentiated by treatment with desmethylimipramine which completely blocked the action of tyramine. A large amount of MnCl 2 suppressed the actions of both papaverine and norepinephrine. Paparevine-induced negative chronotropic and inotropic effects were not influenced by atropine treatment. In addition, papaverine slightly potentiated the negative chronotropic responses to adenosine. From these results, it appears that paparevine has a direct stimulating property on sinus rate and atrial contractility which may be due to inhibition of phosphodiesterase and successive accumulation of cyclic AMP. Moreover, paparevine may partially cause catecholamine release from adrenergic nerve fibers and it may inhibit the adenosine uptake mechanism.

Trans-synaptic regulation of the development of end organ innervation by sympathetic neurons

To examine the regulation of development of end organ innervation the superior cervical ganglion (SCG), and two of its target organs, the iris and pineal gland, were studied using biochemical and histofluorescence approaches. During postnatal ontogeny the activity of tyrosine hydroxylase (T-OH), which is localized to adrenergic neurons, increased 50-fold in iris, and 34-fold in pineal nerve terminals of the rat. These increases paralleled the in vitro rise in iris [ 3H]norepinephrine 9[ 3H]NE) uptake, a measure of the presence of functional nerve terminal membrane. These biochemical indices of end organ innervation correlated well with developmental increases in density of innervation, adrenergic ground plexus ramification and nerve fiber fluorescence intensity as determined by fluorescence microscopy. Unilateral transection of the presynaptic cholinergic nerves innervating the SCG in 2–3-day-old rats prevented the normal development of end organ innervation: T-OH activity, [ 3H]NE uptake, innervation density, plexus ramification and fluorescence intensity failed to develop normally in irides innervated by decentralized ganglia. It is concluded that trans-synaptic factors regulate the maturation of adrenergic nerve terminals, and the development of end organ innervation by SCG.

Role of the cervical sympathetic ganglia on neurogenic control and autoregulation of basilar arterial flow (authors transl)

In recent years the presence of adrenergic nerve fibers on cerebral arteries as small as 10 to 15 μ both on the pial and within the brain substance has been confirmed morphologically. Although possible roles of the adrenergic fibers in control of cerebral circulation are fairly well clarified, there are few studies as to neural factors in the territory of the basilar artery. In the present study, electrical stimulation of the superior cervical ganglion (SCG) was performed to define the contribution of neural mechanism to control of basilar arterial flow. Studies were also made to determine the effects of hexamethonium(C6)and chronic bilateral superior cervical ganglionectomy on autoregulation mechanism and CO2 reactivity in the territory of the basilar artery. Fifty-two mongrel adult dogs weighing 8 to 26 kg were anesthetized with pentobarbital and mechanically ventilated. The basilar artery was exposed through the transcervical-transclival approach and the flow was measured with an electromagnetic flowmeter. The unilateral and bilateral SCG were stimulated by square-wave direct current impulses (3-5 v, 2.0 msec duration, 20 Hz). Autoregulation of basilar flow was studied under acute hypertension, which was induced by an intraaortic balloon inflation before and after intravenous administration of C6. The same study was performed in the animals, in which both SCG were removed 2 weeks to 2 months prior to the experiment. Also changes in basilar flow following 7 % CO2 inhalation were studied in the respective experiments. The mean percentage reduction of basilar flow was 11.7% on unilateral SCG stimulation and 20.4% on bilateral, associated with a slight rise of systemic blood pressure. The effects of bilateral stimulation were greater than those of unilateral (p<0.01). Inflation of the balloon produced an increase in basilar flow. However, it returned rapidly to the resting level and remained unchanged during 3 minutes period of induced hypertension. After the administration of C6, basilar flow increased along with the rise of blood pressure. CO2 reactivity was well maintained under this condition. Two to four weeks after bilateral SCG-ectomy, fluorescence of the adrenergic fibers disappeared completely from the trunk and main superficial branches of the basilar artery. Studies using chronically bilaterally sympathectomized dogs revealed an impairment of autoregulation in response to rise of blood pressure. Adrenergic fibers observed in abundance on the basilar artery may have an important functional role in conveying vasoconstrictive impulses via the SCG. It is assumed that the bilateral SCG contribute to neurogenic control of blood flow in the territory of the basilar artery and the neurogenic control plays an important role in autoregulation of cerebral blood flow in response to rise of blood pressure.

Cholinergic innervation of vessels of the base of the brain

Distribution and activity of acetylcholinesterase in the intramural nerve apparatus of vessels of the base of the bran have been studied with the histochemical method of Koelle-Gomori. On the whole, 268 arteries have been examined. The activity of the ferment is detected in the effector nerve fibers in the wall of all cerebral vessels constituting the system of the circle of Willis. The periarterial nerve apparatus of cerebral arteries of the anterior and posterior regions of the circle of Willis consists of two cholinergic plexuses - superficial and deep plexus forming a multilayered neural cover. The terminal parts of cholinergic nerve fibres at the border with the muscular coat show a granular structure. Moreover, nerve cells rich in active ferment are found in the cholinergic plexuses. Difference in the character of cholinergic innervation of vessels of the internal carotid and the vertebrobasilar region has been shown. The obtained data indicate that the vessels of the circle of Willis possess a reliable cholinergic system of nerve regulation which along with other systems, such as that of adrenergic nerve fibers, maintains the homeostasis of the cerebral blood flow.

Fluorescence histochemical study of Auerbach’s plexus of the ileum of 6-hydroxydopamine-treated guinea pig

In the present investigation the action of 6-hydroxydopamine (6-OHDA) on Auerbach's plexus of the ileum of the guinea pig has been studied with Falck and Hillarp's histochemical technique. A singel dose of 15-25 mg/kg of 6-OHDA causes degeneration of some of the adrenergic nerve fibres after 6 h of treatment. 200-250 mg/kg of 6-OHDA is responsible for the total disappearance of nerve fibres in the ganglia and internodal strands within 24 h. 6 h after 100 mg/kg of 6-OHDA treatment, the intervaricose fibres have mostly disappeared and a few nerve fibres are swollen. The pre-terminal fibres are not much affected. After 24 and 48 h of 100 mg/kg treatment with 6-OHDA, most of the varicose and non-varicose fibres have disappeared and very few fibres are left, these having become intensely fluorescent and much swollen, probably due to the accumulation of storage granules transported to this site by axoplasmic flow. After 6-8 days of treatment with 6-OHDA all the fluorescen fibres and cell bodies have disappeared. A few faintly fluorescent green and yellow cell bodies could also be observed; however, their chemical nature could not be determined.

Effects of dopamine on sinus rate and ventricular contractile force of the dog heart in vitro and in vivo.

1 Experiments were carried out on dog isolated papillary muscle and sinus node preparations perfused with arterial blood from a donor dog. The chronotropic and inotropic effects of dopamine were analysed by using reserpine, desmethylimipramine (DMI), cocaine and phenoxybenzamine, and the relative chronotropic and inotropic effects defined, the results being compared with those for noradrenaline (NA). 2 The effects of dopamine administered intra-arterially into the isolated preparations were reduced by pretreatment of animals with reserpine both in the papillary muscle and sinus node. The chronotropic effects, however, were affected less by pretreatment with reserpine than were the inotropic effects. 3 Desmethylimipramine (DMI) reduced the inotropic and chronotropic effects of dopamine, and enhanced the effects of NA and nerve stimulation; the chronotropic effects of the amines were less affected than the inotropic effects. 4 Cocaine enhanced considerably the inotropic and chronotropic effects of NA, and decreased the inotropic but not the chronotropic effect of dopamine. 5 Phenoxybenzamine enhanced the inotropic effects of dopamine, NA and nerve stimulation, but did not affect the chronotropic effects of the amines. 6 When dopamine (1 to 300 mug/kg) was administered intravenously to the donor dog, it increased preferentially the contractile force of the ventricular myocardium with a comparatively small change of the sinus rate in the isolated preparations as well as in the heart in vivo. NA (0.1 to 10 mug/kg) caused effects similar to those of dopamine. The maximal inotropic responses to these catecholamines were reached with lower doses than the chronotropic ones. 7 It is concluded that both the positive inotropic and the positive chronotropic responses to dopamine are mediated partially by a direct and partially by an indirect stimulant effect on beta-adrenoceptors in the dog heart. The present results suggest that the difference in activity of dopamine and NA between the ventricular myocardium and the sinus node may be ascribed to the unequal innervation with adrenergic nerve fibres of the atrium and the ventricle (Furnival, Linden & Snow, 1971). The sinus node which is densely innervated by adrenergic nerve fibres may inactivate noradrenaline and dopamine more effectively than the ventricular myocardium through the uptake into the nerve and thereby be less sensitive to the exogenous catecholamines.

Light and electron microscopic studies on the excessive growth of sympathetic ganglia in rats injected daily from birth with 6-OHDA and NGF.

Concomitatn daily treatment of rats immediately after birth with NGF and 6-OHDA for a period of 2-4 weeks, results in a volume increase of sympathetic ganglia of thirty times that of controls and 2.3 that of NGF treated littermates, at three weeks of age. Studies at the light, fluorescent and electron-microscope, showed that this overall enlargement is due to increase in size and number of sympathetic neurons and, to an even higher extent, to profuse production and branching of collaterals from postganglionic adrenergic nerve fibers. These axonal collaterals find accomodation inside the ganglia where they displace nerve cells and build a thick fibrillar capsule around the same ganglia. The survival in excellent conditions of sympathetic nerve cells treated with NGF but prevented by 6-OHDA from establishing anatomical and functional connections with their end organs, suggests that the growth factor find access to its target cells through the plasms membrane which envelops the cell perikarya. The extraordinary production of collaterals by chemically axotomized sympathetic fibers, brings to light growth potentialities of these fibers which materialize only upon disconnection of their endings from peripheral tissues. These results uncover a new facet of the interaction between nerve fibers and innervated tissues.

Effects on gastric motility from the cerebellar fastigial nucleus.

In acute experiments on chloralosed cats gastric motility, blood pressure and heart rate were investigated for influences exerted by the fastigial nucleus. Besides pressor responses, fastigial stimulation could produce either gastric excitation or relaxation and the background of these responses was analysed by selective nerve sectioning and administration of suitable autonomic blocking agents. Suppression of prevailing gastric motility was found to be mediated mainly by increased discharge in adrenergic nerve fibres but also by adrenal catecholamine release. -- Gastric excitation could be induced in three different ways, first via increased activity in vagal cholinergic fibres, second, by fastigial suppression of the vago-vagal non-adrenergic relaxatory reflex. In addition, when laparotomy or other noxious abdominal stimuli had induced inhibitory gastric reflexes, the consequent sympathetic discharge could be suppressed by fastigial stimulation resulting in enhanced gastric motility. -- The importance of background activity in the various nervous pathways for the fastigially induced gastric responses is discussed.

Action of morphine on guinea-pig myenteric plexus and mouse vas deferens studied by intracellular recording

Morphine reduces the output of transmitter from the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum and from the mouse vas deferens. Intracellular recordings were made from ganglion cells of the myenteric plexus and smooth muscle cells of the vas deferens. Synaptic transmission within the myenteric plexus was blocked by hexamethonium. Morphine did not change the properties of the ganglion cells, nor did it affect synaptic potentials. 5-Hydroxytryptamine inhibited acetylcholine release at intraganglionic synapses by an action which was unaffected by morphine. In the vas deferens, excitatory junction potentials were elicited by stimulation of postganglionic adrenergic nerve fibres. The junction potentials were depressed by morphine and levorphanol but not by dextrorphan. This depression was reversed by naloxone. The results indicate that morphine acts directly to reduce transmitter release at the neuro-effector junctions in the myenteric plexus-longitudinal muscle preparation and in the vas deferens in these species.

Catecholamine luminescence reaction in neurons of the spinal sensory ganglion

The spinal ganglia of 45 cats were studied by the method of Falck and Hillarp in Krokhina's modification, and parallel investigations were made by Nissl and Unna's methods, staining for lipofuscin, and by the Masson-Fontana method for serotonin. Two types of neurons were discovered: neurons of one type had yellowish-white granules in the region of the axon hillock and speckled yellowish granules and diffuse greenish luminescence in the perikaryon, while those of the second type had orange granules, gathered into small clumps all over the region of the perikaryon. Neurons of both types were surrounded by single adrenergic nerve fibers.

Effects of myocardial infarction on adrenergic nerves of the rat heart muscle, a histochemical study.

The anterior branch of the left coronary artery of the rat heart was ligated and the effects of anoxia on adrenergic nerves were studied histochemically using formaldehyde-induced fluorescence for localization of norepinephrine. Greenish catecholamine fluorescence was associated in the normal or infarcted myocardium only with adrenergic nerves. Constant but not prominent changes were seen in adrenergic nerve fibers 2 or 4 h after ligation of the coronary artery; the number of dilicate adrenergic fibers was reduced and some diffusion of the histochemical reaction was seen in small areas of the infarcted myocardium. Strong effects of anoxia were seen 8 h or more after ligation of the coronary artery. These were characterized by a prominent diffusion of the histochemical reaction and gradual disappearance of adrenergic structures in 2 to 4 days of anoxia. During the healing phase the appearance of numerous adrenergic nerve fibers was closely connected with the ingrowth of a new vascular bed into the infarction area. The observations indicate that adrenergic nervous structures of the myocardium resist the effects of anoxia, which may indicate the viability of sympathetic nerves in the infarcted area during long periods of anoxia.

The effect of brain stem lesions on vasomotor nerves and the smooth muscle of the cerebral arteries--a morphological study.

A morphological study was performed on the nerve fibers and the smooth muscle of the cerebral arteries in human brains with hypertensive intracerebral hematomas. In addition, an experimental study was also performed on dogs. Immediately after autopsy, the nerve fibers on the Willis circle and its main branches in five patients with hypertensive intracerebral hematomas were examined with Falck and Hillarp's fluorescent method and with Koelle's thiocholine method. The smooth muscle of the main cerebral arteries from ten brains with intracerebral hematomas, which had been preserved in 10% formalin, was studied with histochemical examinations. Bilateral hypothalamic lesions were made experimentally in 16 dogs, and the nerve fibers and the smooth muscle of the main cerebral arteries were examined by the histochemical method and with an electron-microscope. No adrenergic fibers were seen with the fluorescent method in any of the five patients. The cholinergic nerve fibers on the same arteries were observed with the thiocholine method. Examinations for cholinergic nerve fibers of arteries from the affected cerebral hemispheres of two patients did not show any enzymatic activity, while it was shown to be present in the intact hemisphere. Ten brains showed degeneration of the smooth muscle cells in the tunica media. Animal studies showed a decrease of the adrenergic and cholinergic nerve fibers from experimental hypothalamic injuries. The degeneration of the nerve fibers was observed with electron-microscopic examinations. Thus our findings in this study suggest that brain stem damage leads to the degeneration of the smooth muscle together with the adrenergic and cholinergic nerve fibers of the cerebral artery.

A fluorescence and electron microscopic study of the adrenergic innervation in the vestibular ganglion and sensory areas.

The adrenergic innervation in the vestibular ganglion and sensory areas in rabbit and cat was studied with fluorescence and electron microscopic techniques. All adrenergic nerve fibres consisted of postganglionic axons from the ipsilateral superior cervical ganglion. In rabbit, postganglionic nerve fibres passed via the carotic plexus. Probably because of the anatomical difference, the feline internal carotic artery being rudimentary, all sympathetic nerve fibres to the inner ear in cat passed via the tympanic plexus. In the vestibular ganglion there was a uniform distribution of adrenergic nerve fibres and there was no difference in distribution patterns between rabbit and cat. There was a continuous blood vessel innervation and an innervation independent of blood vessles. The adrenergic innervation extended to the sensory areas but did not seem to penetrate the basement membrane and no adrenergic nerve terminals were found in direct contact with sensory or secretory cells.

Absence of muscarinic modulation of vasopressin release from the isolated rat neurophypophysis.

1. Isolated rat neurohypophyses were incubated in Locke solution at 37 degress C and the vasopressin output into the medium determined by bioassay. 2. Potassium chloride 60 mM caused a 9-fold increase in the rate of vasopressin release that was abolished when calcium chloride was omitted from the Locke solution. 3. Acetylcholine 5.5x10-4M neither alone nor in the presence of atropine 2.9x10-6M changed the "resting" release of vasopressin. 4. Neither acetylcholine 5.5x10-4M oxotremorine 10-4 and k3x10-4M altered the vasopressin release evoked by potassium chloride 60 mM. 5. In contrast to the peripheral adrenergic nerve fibres, the secretory terminal fibres of the neurohypophysis do not appear to contain muscarinic inhibitory or nicotinic excitatory receptors.