Adrenergic Nerve Fibers Research Articles

Differential Effects of Estradiol, Progesterone, and Testosterone on Vaginal Structural Integrity

Ovarian steroids are known to be important in maintaining vaginal tissue, and evidence is mounting that imbalances in the hormonal milieu contribute to vaginal pathophysiology. To date, limited data are available on the effects of hormone deprivation and replacement on vaginal tissue morphology and vaginal innervation. The goal of this study was to assess the dynamic changes in vaginal tissue structure in response to sex steroid hormone deprivation and administration. Female Sprague-Dawley rats were either kept intact (controls) or ovariectomized. Ovariectomized animals were treated with vehicle, estradiol, testosterone, progesterone, or a combination of estradiol plus testosterone or progesterone. Histological techniques, including stereological analysis and immunohistochemistry for localization of neuronal markers, were used. Ovariectomy produced a significant decrease in epithelial height that was restored with estradiol replacement. Interestingly, a subphysiological dose of estradiol resulted in hyperplasia of the vaginal epithelium and nonvascular smooth muscle. Neither testosterone nor progesterone had a significant effect on epithelial height or muscularis thickness. However, testosterone treatment resulted in a significant increase in small adrenergic nerve fibers. Addition of either testosterone or progesterone to estradiol mitigated but did not abolish the effects of estradiol alone. This study demonstrates that estradiol and testosterone have differential effects on vaginal tissue parameters and that ovarian hormones are critical for the maintenance of genital tissue structure. Present observations also suggest that combined replacement regimens may be required for an optimal physiological response.

Cholinergic and adrenergic innervation of lingual salt glands of the estuarine crocodile, Crocodylus porosus

Many marine reptiles and birds possess extrarenal salt glands that facilitate the excretion of excess sodium and chloride ions accumulated as a consequence of living in saline environments. Control of the secretory activity of avian salt glands is under neural control, but little information is available on the control of reptilian salt glands. Innervation of the lingual salt glands of the salt water crocodile, Crocodylus porosus, was examined in salt water-acclimated animals using histological methods. Extensive networks of both cholinergic and adrenergic nerve fibres were identified close to salt-secreting lobules and vasculature. The identification of both catecholamine-containing and cholinergic neurons in the salt gland epithelium and close to major blood vessels in the tissue suggests the action of the neurotransmitters on the salt-secreting epithelium itself and the rich vascular network of the lingual salt glands.

Distribution of Catecholaminergic Neurotransmitters and Related Receptors in Human Bronchus-Associated Lymphoid Tissue

Background: The functions of the bronchus-associated lymphoid tissue (BALT) are under the control of the autonomic nervous system (sympathetic and parasympathetic nerve fibers). Objectives: The relationships between the adrenergic nerve fibers and β-adrenergic receptors were studied in the human BALT with the aim to demonstrate a probable neuromodulation. Methods: Morphological observations (staining with hematoxylin-eosin and scanning electron microscopy images) were carried out on samples of human BALT harvested during autopsies. Moreover, histochemical staining for norepinephrine (adrenaline = adrenergic nerve fibers) as well as for other catecholamines was performed. Finally, β-adrenergic receptors were stained by means of a β-blocking, radiolabeled drug (pindolol ¹²⁵I). All our data were submitted to morphometric analysis (quantitative analysis of images and statistical analysis of data). Results: Our results provide direct evidence of the presence and distribution of catecholaminergic nerve fibers and related β-adrenergic receptors in BALT. β-Adrenergic receptors are present above all in the most richly innervated part of the BALT, and are, therefore, in close relationship with their related adrenergic nerve fibers. Conclusions: Studies on the distribution of adrenergicneurotransmitters and related β-adrenergic receptors in the human BALT are the first step for the demonstration of a probable neuromodulation of BALT.

Comparaison de l’activité réflexe de l’utérus au cours de l’insémination artificielle et de l’accouplement chez la brebis

To identify and to compare the reflex mechanisms involved in the activation of the uterine motility following artificial insemination (AI) and mating in the ewe. The contractile activity of the uterus was monitored in presence and absence of adrenergic (phentolamine) and cholinergic (atropine) antagonists, using an implantable telemetric device equipped with a sensor catheter inserted into the uterine lumen, and connected to a radio-telemetric transmitter. During AI, a uterine contraction (UC) of short duration (<20 seconds) appeared in direct response to animal restraint, to the speculum introduction, then when the speculum was opened. Both the UC evoked by restraint of the ewe and insertion of the speculum were abolished in presence of phentolamine, while atropine inhibited the UC in response to opening of the speculum only. After AI, the uterine activity increased sharply and was all the more intense and extended with higher vaginal wall pressure. Phentolamine or atropine did not inhibit this motor response, whereas a similar pattern of uterine hyperactivity occurred following i.v. injection of oxytocin (100 and 200 mIU; Syntocinon). After mating, an increase in uterine activity was never observed. Only penis intromission evoked a UC of short duration (about 20 seconds), abolished in presence of phentolamine only. Artificial insemination in the ewe increases uterine motility, resulting from the reflex activation of adrenergic and cholinergic nerve fibres of the autonomic nervous system, following by a reflex release of oxytocin from the pituitary gland (also called "Ferguson reflex"). This secretion of OT was elicited by the excessive dilation of the vaginal wall with the speculum. By comparison, mating did not evoke a period of uterine hyperactivity and respects the physiological post-coital resting period.

Pregnancy-induced changes in substance P and neurokinin 1 receptor (NK1-R) expression in the rat uterus

Adrenergic nerve fibres of the mammalian uterus degenerate during pregnancy. The behaviour of peptidergic fibres, such as substance P-positive fibres and of its preferred neurokinin 1 receptor (NK1-R), is poorly studied in the pregnant rat uterus. The present study analysed the changes in substance P immunoreactivity and in the expression of NK1-R protein in the uterus of non-pregnant, pregnant (days 7, 14 and 21) and postpartum rats (days 1, 8 and 22) by immunohistology, dot blot analysis and western blot analysis. In non-pregnant rats, substance P-positive fibres were localized to the myometrium; these fibres progressively disappeared during gestation and were almost absent at term (day 21). At day 22 post partum, substance P-positive fibres had recovered to numbers comparable with those in the non-pregnant uterus. Dot blot analysis revealed a significant decrease in the immunoreactivity of substance P in the uterus at mid-pregnancy (day 14) and especially at term. Expression of the NK1-R protein showed a progressive increase throughout pregnancy reaching a peak on day 1 post partum; downregulation of NK1-R protein occurred on day 8 post partum. The low and high expressions of NK1-R protein were coincident with a large number of eosinophils and almost no eosinophils in the uterus at oestrus and at term, respectively. It was concluded that substance P immunoreactivity is inversely correlated with NK1-R protein expression in the pregnant and postpartum uterus. The marked upregulation of NK1-R protein at term and after birth indicates that the NK1-R may be involved in the complex regulation of labour and postpartum physiology. However, it is likely that the NK1-protein is not involved in the recruitment of eosinophils into the uterus at oestrus.

Pregnancy-induced changes in substance P and neurokinin 1 receptor (NK1-R) expression in the rat uterus.

Adrenergic nerve fibres of the mammalian uterus degenerate during pregnancy. The behaviour of peptidergic fibres, such as substance P-positive fibres and of its preferred neurokinin 1 receptor (NK1-R), is poorly studied in the pregnant rat uterus. The present study analysed the changes in substance P immunoreactivity and in the expression of NK1-R protein in the uterus of non-pregnant, pregnant (days 7, 14 and 21) and postpartum rats (days 1, 8 and 22) by immunohistology, dot blot analysis and western blot analysis. In non-pregnant rats, substance P-positive fibres were localized to the myometrium; these fibres progressively disappeared during gestation and were almost absent at term (day 21). At day 22 post partum, substance P-positive fibres had recovered to numbers comparable with those in the non-pregnant uterus. Dot blot analysis revealed a significant decrease in the immunoreactivity of substance P in the uterus at mid-pregnancy (day 14) and especially at term. Expression of the NK1-R protein showed a progressive increase throughout pregnancy reaching a peak on day 1 post partum; downregulation of NK1-R protein occurred on day 8 post partum. The low and high expressions of NK1-R protein were coincident with a large number of eosinophils and almost no eosinophils in the uterus at oestrus and at term, respectively. It was concluded that substance P immunoreactivity is inversely correlated with NK1-R protein expression in the pregnant and postpartum uterus. The marked upregulation of NK1-R protein at term and after birth indicates that the NK1-R may be involved in the complex regulation of labour and postpartum physiology. However, it is likely that the NK1-protein is not involved in the recruitment of eosinophils into the uterus at oestrus.

Pharmacological characterization of the presynaptic activity of Tityus serrulatus venom in the rat anococcygeus muscle

Scorpion venoms are known to cause peripheral nerve stimulation with enhanced autonomic responses. This study, therefore, examined the effects of Tityus serrulatus venom (TSV) on adrenergic, cholinergic and nitrergic nerve fibers using the rat anococcygeus muscle. The contractile effects of TSV (1 μg/ml) and electrical field stimulation were markedly reduced by phentolamine (5 μM), prazosin (0.1 μM), guanethidine (30 μM) and tetrodotoxin (TTX, 1 μM), whereas imipramine (3 μM) enhanced these responses. The responses to tyramine (10 μM) were partially reduced by guanethidine and completely blocked by phentolamine, prazosin and imipramine. Atropine (1 μM) fully prevented carbachol (CCh, 30 μM)-induced contractions without affecting those mediated by TSV. Neostigmine significantly potentiated TSV-and ACh-evoked contractions, whereas hexamethonium had no effect. The relaxant responses induced by EFS and TSV (3 μg/ml) were completely blocked by l-NAME (100 μM), ODQ (1 μM) or TTX (1 μM). Addition of l-arginine (1 mM) reversed the effect of l-NAME. Thus, the motor and inhibitory responses of TSV in the rat anococcygeus muscle are mediated by prejunctional mechanisms dependent on Na+ channel activation, causing the stimulation of NA and NO release from adrenergic and nitrergic nerve fibers, respectively.

NANC nerves in the respiratory air sac and branchial vasculature of the indian catfish, Heteropneustes fossilis

Gill and air sac of the Indian catfish Heteropneustes fossilis harbour a nerve network comprising an innervated system of neuroepithelial endocrine cells; the latter cells are found especially in the gill. A series of antibodies was used for the immunohistochemical detection of neurotransmitters of the neural non-adrenergic, non-cholinergic (NANC) systems such as the sensory neuropeptides (enkephalins), the inhibitory neuropeptide VIP and neuronal nitric oxide synthase (nNOS) responsible for nitric oxide (NO) production which is an inhibitory NANC neurotransmitter. NADPH-diaphorase (NADPH-d) histochemistry was used as marker of nNOS although it is not a specific indicator of constitutively-expressed NOS in gill and air sac tissues. A tyrosine hydroxylase antibody was used to investigate adrenergic innervation. Nitrergic and VIP-positive sensory innervation was found to be shared by gill and air sac. Immunohistochemistry revealed the presence of enkephalins, VIP, NOS and NADPH-d in nerves associated with branchial and air sac vasculature, and in the neuroendocrine cell systems of the gill. Adrenergic nerve fibers were found in some parts of the air sac vasculature. The origin of the nerve fibers remains unclear despite previous findings showing the presence of both NADPH-d and nNOS in the sensory system of the glossopharyngeal and vagus nerves including the branchial structure. Scarce faintly stained nNOS-positive neurons were located in the gill but were never detected in the air sac. These findings lead to the conclusion that a postganglionic innervation of the airways is absent. Mucous goblet cells in the gill were found to express nNOS and those located in the non-respiratory interlamellar areas of the air sac were densely innervated by nNOS-positive and VIP-positive nerve fibers. Our immunohistochemical studies demonstrate that most arteries of the gill and air sac share a NANC (basically nitrergic) innervation which strongly suggests that they are homologous structures.

Distribution of ganglionic sympathetic neurons supplying the subcutaneous, perirenal and mesentery fat tissue depots in the pig

Previous morphological studies revealed that the adipose tissue is innervated by adrenergic nerve fibers. Furthermore, physiological studies showed that the metabolism of adipose tissue is controlled by the adrenergic component of the nervous system. However, nothing is known on the sources of innervation of different fat tissue depots. Therefore, we decided to study the distribution of ganglionic sympathetic neurons innervating adipose tissue in the pig by means of a retrograde tracing method. We used 9 male and 9 female pigs of approximately 50 kg body weight. The retrograde tracer, Fast Blue (FB), was injected into the subcutaneous, perirenal and mesentery fat tissue depots. Results of the present study showed that numerous centers of the sympathetic nervous system innervate adipose tissue in the pig. FB+ neurons projecting to the subcutaneous fat tissue were placed in the thoraco-lumbar region of the sympathetic chain ganglia (SChG). However, neurons supplying perirenal and mesentery fat tissue depots were found in both the SChG and prevertebral ganglia (PVG). We conclude that different adipose tissue depots (subcutaneous, perirenal and mesentery) have different sources of innervation and that there is no significant difference in the distribution of neurons innervating adipose tissue in male and female pigs.

Effect of interferon on human thymus microenvironment

Interferon, a thymic immunostimulator, was used with the aim of assessing the importance of adrenergic nerve fibers (ANF) and/or AChE-positive nerve fibers (AChENF) in the regulation of some immunological functions in humans. Thymic normal control fragments and/or thymic fragments of immunostimulated patients were removed during surgical biopsies. Thymic slices were stained with eosin-orange (for the recognition of microanatomical details of the microenvironment) and with Bodian's method for staining of nerve fibers. Histofluorescence microscopy was employed for staining ANF. AChENFs were detected by means of the direct-coloring thiocholine method. All images were submitted to quantitative morphometrical analysis and statistical comparisons of data. Moreover, the amount of proteins and noradrenaline was measured on thymic homogenates of the same patients. Treatment with interferon induces substantial changes in the thymic microenvironment, on ANF, on AChENFs and on the total amount of proteins and noradrenaline in thymic tissue homogenates. In conclusion immunostimulation with interferon induces substantial changes in the whole thymus and in its microenvironment, involving both sympathetic and parasympathetic nerve fibers.

Functional and histochemical characterization of a uterine adrenergic denervation process in pregnant rats.

The time course of pregnancy-induced changes in the contractile responses of isolated uterine rings and sympathetic innervation pattern were studied using electric field stimulation and histofluorescence techniques, respectively, in intact and 6-hydroxydopamine-treated rats. Neurally mediated contractions elicited by field stimulation (0.6 msec, 1-70 Hz, 40 V) were measured in uterine preparations obtained from nonpregnant, 6-hydroxydopamine-treated and 5-, 10-, 15-, 18-, and 22-day (term) pregnant rats. At all frequencies, the amplitudes of contractions were highest in nonpregnant uteri. Stimulation at 1-2.5 Hz evoked contractions in 10-day pregnant uteri but failed to cause contractions on Day 5 and from Day 15 onward. In uterine preparations obtained from term and from 6-hydroxydopamine-treated rats, contractions could not be evoked by stimulation at 1-20 Hz. Fluorescence histochemistry of uterine adrenergic nerves revealed rich perivascular and myometrial innervation in nonpregnant and in pregnant rats through Day 10. Degeneration and loss of adrenergic nerve fibers was apparent by Day 15, and fluorescent myometrial and perivascular nerves were practically absent by Day 22. These findings demonstrate a progressive, frequency-related reduction of nerve-mediated uterine contractions beginning in midterm pregnancy, in parallel with a gradual loss of adrenergic nerve fibers. Pregnancy-induced nerve degeneration may promote the development of nonsynaptic alpha-adrenergic uterine contractile activity towards term. The reduced responsiveness of uterine smooth muscle to electric field stimulation in early pregnancy appears to be unrelated to alterations in uterine innervation but may be related to changes associated with implantation.

Adrenergic nerve fibres and mast cells:: correlation in rat thymus

The interactions between adrenergic nerve fibres and mast cells (MCs) were studied in the thymus of adult and old rats by morphological methods and by quantitative analysis of images (QAIs). The whole thymus was drawn in adult (12 months old) rats: normal, sympathectomized or electrostimulated. Thymuses from the above-mentioned animals were weighed, measured and dissected. Thymic slices were stained with eosin orange for detection of microanatomical details and with Bodian's method for identification of the whole nerve fibres. Thymic MCs were stained with Astrablau. Histofluorescence microscopy was used for staining of adrenergic nerve fibres. Finally, all morphological results were submitted to the QAIs and statistical analysis of data. Our results suggest that after surgical sympathectomy, the greater part of adrenergic nerve fibres disappear while related MCs appear to show less evident fluorescence and few granules. On the contrary, electrostimulation of the cervical superior ganglion induced an increase in the fluorescence of adrenergic nerve fibres and of related MCs.

Adrenergic and Cholinergic Innervation of the Mammary Gland in the Pig

Adrenergic and acetylcholinesterase-positive (AChE-positive) innervation of the mammary gland in the sexually immature and mature pigs was studied using histochemical methods. Upon examining the adrenergic and cholinergic innervation, the adrenergic innervation was found to be much more developed. The majority of both sub-populations of the nerve fibres studied was localized in the subcutaneous tissue of the mammary gland. Adrenergic and AChE-positive nerve fibres also supplied structures of the nipple (subcutaneous tissue, blood vessels, smooth muscles fibres) and glandular tissue (blood vessels, lactiferous ducts). The glandular tissue contained the smallest number of adrenergic and AChE-positive nerve fibres. No distinct differences were observed in the adrenergic and AChE-positive innervation of the porcine mammary gland between the juvenile and non-pregnant adult animals.

Adrenergic and acetylcholinesterase-positive innervation of palatine tonsils in mammals

Innervation of human, feline and rabbit palatine tonsils was investigated. Adrenergic nerve components were visualized by formaldehyde-induced fluorescence of catecholamines and 5-HT, or by glyoxylic acid fluorescence, whereas acetylcholinesterase (AChE)-positive nerve structures were demonstrated by the direct thiocholine method. The largest density of adrenergic and AChE-positive nerve profiles was found in the adventitia of arterial branches in the fibrous capsula and septa, mainly in the form of periarterial nerve plexuses of different density. Fine nerve fibres lined the wall of small arteries which penetrated into extrafollicular lymphoid tissue and marginal layers of follicles. It is concluded that there are significant species-specific differences related to density, nature and topographic relations of adrenergic and AChE-positive nerve fibres in the various structural parts of palatine tonsils.

Occurrence of adrenergic nerve fibers in human thymus during immune response

The adrenergic nerve fibers (ANF), the neuropeptide Y-like immunoreactive nerve fibers (NPY-NF) and the noradrenaline (NA) amount were studied in the human thymus in subjects previously treated or not treated with interferon therapy with the aim to identify the changes due to the interferon therapy. This therapy has been used in patients affected by multiple sclerosis (MS). Biochemical and morphological methods were used associated with quantitative analysis of images. The whole thymuses were removed during autopsies in young and adult patients not treated with interferon. Moreover, samples of thymus were removed from patients, either young or adult who had previously been treated with interferon therapy, and subjected, for diagnostic reasons, to thymic biopsy. All samples of thymus were weighed, measured and dissected. Thymic slices were stained with Eosin-orange for detection of the microanatomical details, or with Bodian's reaction for recognition of nervous structures. Histofluorescence microscopy was used for detection of ANF, and immunofluorescence microscopy for recognition of NPY-like immunoreactive structures. All morphological results were subjected to quantitative analysis of images. Noradrenaline contained in thymic structures was measured by biochemical methods. Our results only concerned the effects of the therapy and suggested that treatment with interferon therapy induces many changes in the thymic structures: (1) The protein content of thymus is significantly increased; (2) the NA content in the thymus is also significantly increased; (3) NPY-like immunoreactive structures in the thymus are significantly increased; (4) occurrence of NPY-like immunoreactivity is particularly and significantly increased both in thymic microenvironment and in structures resembling nerve fibers; (5) ANF are significantly increased in the same thymic structures in which NPY-like immunoreactivity is also increased (i.e. thymic microenvironment and structures resembling nerve fibers). The morphological and biochemical changes observed can also explain the immunological changes induced in the thymus after immunostimulating therapy.

Immunohistochemical study of the distribution of adrenergic and peptidergic innervation in the equine uterus and the cervix.

Little is known about neurogenic regulation of uterine contractility in mares. The present study investigated the distribution of adrenergic and peptidergic nerves in the mare uterus. Samples from the uterine horn, body and cervix were collected from 18 cyclic mares for immunohistochemistry. The uterus was well supplied with adrenergic nerves. A large number of tyrosine hydroxylase- and dopamine beta-hydroxylase-immunoreactive nerve bundles and fibres were present in the myometrium and endometrium in all regions of the uterus and cervix. These adrenergic nerve bundles and fibres travelled parallel to the muscle layers and were often associated with blood vessels. The density of peptidergic nerves was less than that of adrenergic nerves, but the pattern of distribution was similar. Neuropeptide Y-immunoreactive nerve fibres were the most abundant, whereas vasoactive intestinal polypeptide- and calcitonin gene-related peptide-immunoreactive nerve fibres were less frequently seen. Substance P-immunoreactive nerve fibres were the most sparse. Peptidergic nerves were distributed among the smooth muscle layers and near endometrial glands and were often associated with blood vessels in all regions of the uterus. The density of peptidergic nerve fibres was similar in the uterine horn and body but was slightly denser in the cervix. These findings indicate that uterine innervation may have an important role in controlling reproductive functions in mares.

Immunohistochemical study of the distribution of adrenergic and peptidergic innervation in the equine uterus and the cervix

Little is known about neurogenic regulation of uterine contractility in mares. The present study investigated the distribution of adrenergic and peptidergic nerves in the mare uterus. Samples from the uterine horn, body and cervix were collected from 18 cyclic mares for immunohistochemistry. The uterus was well supplied with adrenergic nerves. A large number of tyrosine hydroxylase- and dopamine beta-hydroxylase-immunoreactive nerve bundles and fibres were present in the myometrium and endometrium in all regions of the uterus and cervix. These adrenergic nerve bundles and fibres travelled parallel to the muscle layers and were often associated with blood vessels. The density of peptidergic nerves was less than that of adrenergic nerves, but the pattern of distribution was similar. Neuropeptide Y-immunoreactive nerve fibres were the most abundant, whereas vasoactive intestinal polypeptide- and calcitonin gene-related peptide-immunoreactive nerve fibres were less frequently seen. Substance P-immunoreactive nerve fibres were the most sparse. Peptidergic nerves were distributed among the smooth muscle layers and near endometrial glands and were often associated with blood vessels in all regions of the uterus. The density of peptidergic nerve fibres was similar in the uterine horn and body but was slightly denser in the cervix. These findings indicate that uterine innervation may have an important role in controlling reproductive functions in mares.

Mast-cells distribution and colonic mucin composition in Hirschsprung's disease and intestinal neuronal dysplasia.

Intestinal neuronal dysplasia (IND) is a malformation of the enteric plexus that clinically resembles Hirschsprung's disease (HD). In HD, the aganglionic bowel is characterized by the presence of hypertrophic nerve trunks and increased numbers of adrenergic and cholinergic nerve fibers, whereas IND type B (IND-B) is characterized by dysplasia of parasympathetic nerves, hyperganglionosis, and giant ganglia. The aims of this study were to investigate the relationship between the distribution of mast cells (MC) and abnormal neuronal innervation and the impact of abnormal neuronal innervation on colonic epithelial differentiation in relation to the typical innervation abnormalities seen in HD and IND. Full-thickness rectal-biopsy or resected surgical specimens from 15 patients (7 HD, 4 IND, 4 control) were examined by conventional hematoxylin-eosin, periodic acid-Schiff Alcian blue (PAS-AB), toluidine blue staining. The aganglionic and IND-B segments had larger numbers of MC in all layers than the ganglionic and control segments. There was a close relationship between the hypertrophic nerve fibers and the distribution of the MC. In contrast to the aganglionic segments, the mucin composition of the IND-B segments was normal. This finding suggests that innervation anomalies do not reflect epithelial differentiation to the same extent.

Differential expression of the noradrenaline transporter in adrenergic chromaffin cells, ganglion cells and nerve fibres of the rat adrenal medulla

Expression of the noradrenaline transporter (NAT) was identified in various cell and fibre populations of the rat adrenal medulla, examined with immunohistochemistry and confocal microscopy. Immunoreactivity for the catecholamine biosynthetic enzymes tyrosine hydroxylase (TH), aromatic- l-amino-acid decarboxylase (AADC) and dopamine β-hydroxylase (DBH) was present in all chromaffin cells, while phenylethanolamine N-methyltransferase (PNMT) was used to determine adrenergic chromaffin cell groups. Labelling with NAT antibody was predominantly cytoplasmic and colocalised with PNMT immunoreactivity. Noradrenergic chromaffin cells were not NAT immunoreactive. Additionally, NAT antibody labelling demonstrated clusters of ganglion cells (presumably Type I) and nerve fibres. Expression of TH, AADC, DBH, PNMT and NAT mRNA was examined using reverse transcription-polymerase chain reaction (RT-PCR) from adrenal medulla punches and single chromaffin cells, and results were consistent with those obtained with immunocytochemistry. Chromaffin cells and fibres labelled with antibodies against growth associated protein-43 (GAP-43) were not NAT immunoreactive, while ganglion cells were doubled labelled with the two antibodies. The presence of NAT in adrenergic chromaffin cells, and its absence from noradrenergic cells, suggests that the adrenergic cell type is primarily responsible for uptake of catecholamines in the adrenal medulla.

Quantification of Adrenergic Nerve Fibers in Human Thymus at Various Ages

Quantification of Adrenergic Nerve Fibers in Human Thymus at Various Ages