Sympathetic nerve varicosities in close apposition to basolateral membranes of collecting duct epithelial cells of rat kidney.

BACKGROUND: There are reports of sympathetic innervation of the nephron and of P2 purinergic receptors on epithelial cells. Since ATP is a cotransmitter with noradrenaline in sympathetic nerves, the objective of the present study was to re-investigate basolateral innervation of rat renal collecting duct epithelial cells by sympathetic nerves in the context of recent data on the effects of ATP on this nephron segment. METHODS: Kidney sections were processed for electron immunocytochemistry, using tyrosine hydroxylase rabbit polyclonal antibody, with a second layer of biotinylated donkey anti-rabbit antibody and finally extravidin-horseradish peroxidase. Immunoreactivity was visualised with 3,3'-diaminobenzidine and examined with a Philips CM120 transmission electron microscope. RESULTS: Electron microscopic evidence is presented for close apposition of sympathetic nerve varicosities immunolabelled with tyrosine hydroxylase to principal and intercalated type epithelial cells of the collecting duct of the cortical region. CONCLUSIONS: It is suggested that ATP is released as a cotransmitter from sympathetic nerve varicosities to act on basolateral P2 purinoceptors to influence sodium and water (and potentially acid-base) transport, in conjunction with the known (typically inhibitory) actions of autocrine and/or paracrine release of ATP from collecting duct epithelial cells acting via luminal P2 receptors. It is suggested that while luminal responses may dominate under normal physiological conditions, in pathophysiological states, such as stress and dehydration, sympathetic nerves might also be involved in modulating collecting duct fluid and electrolyte transport.

Peptidergic not monoaminergic fibers profusely innervate the young adult human testis.

Numerous studies have reported that intratesticular nerves exert important regulatory effects on the functions of the male gonad; however, as yet little is known about their distribution in the young adult human testis. The purpose of this study was to explore whether peptidergic and adrenergic nerves occur in the male gonad of this age, and, if present, to depict their distribution further. Thirty testes were collected from 15 reproductively healthy donors aged 21-32 years. Antibodies against protein gene product 9.5 (PGP 9.5), neuropeptide Y (NPY), C-terminal flanking peptide of NPY (CPON) and vasoactive intestinal peptide (VIP) were employed for immunohistochemical detection of intratesticular peptidergic nerves, and those against dopamine-beta-hydroxylase (DBH) and 5-hydroxytryptamine (5-HT) for monoaminergic ones. The testicular parenchyma exhibited a rich innervation by PGP 9.5-positive fibers, mainly associated with Leydig cell nests, blood vessels, and seminiferous tubules. Numerous NPY- and CPON-immunoreactive (IR) nerves also appeared in the gonads, but the vast majority were confined to blood vessels. A small number of VIP-IR fibers were detected in some arterioles. By contrast, however, no fibers displaying DBH or 5-HT immunoreactivity were observed within the testis. Additionally, expression of PGP-9.5, NPY, CPON, VIP, DBH and 5-HT was found in Leydig cells, PGP 9.5 in spermatogonia, and NPY and CPON in peritubular myoid cells. Our results suggest that the young adult human testis is devoid of monoaminergic nerves but profusely innervated by peptidergic fibers, which may serve as major neuronal regulators for testicular functions at this age.

Development of the swimbladder and its innervation in the zebrafish, Danio rerio.

Many teleosts including zebrafish, Danio rerio, actively regulate buoyancy with a gas-filled swimbladder, the volume of which is controlled by autonomic reflexes acting on vascular, muscular, and secretory effectors. In this study, we investigated the morphological development of the zebrafish swimbladder together with its effectors and innervation. The swimbladder first formed as a single chamber, which inflated at 1-3 days posthatching (dph), 3.5-4 mm body length. Lateral nerves were already present as demonstrated by the antibody zn-12, and blood vessels had formed in parallel on the cranial aspect to supply blood to anastomotic capillary loops as demonstrated by Tie-2 antibody staining. Neuropeptide Y-(NPY-) like immunoreactive (LIR) fibers appeared early in the single-chambered stage, and vasoactive intestinal polypeptide (VIP)-LIR fibers and cell bodies developed by 10 dph (5 mm). By 18 dph (6 mm), the anterior chamber formed by evagination from the cranial end of the original chamber; both chambers then enlarged with the ductus communicans forming a constriction between them. The parallel blood vessels developed into an arteriovenous rete on the cranial aspect of the posterior chamber and this region was innervated by zn-12-reactive fibers. Tyrosine hydroxylase- (TH-), NPY-, and VIP-LIR fibers also innervated this area and the lateral posterior chamber. Innervation of the early anterior chamber was also demonstrated by VIP-LIR fibers. By 25-30 dph (8-9 mm), a band of smooth muscle formed in the lateral wall of the posterior chamber. Although gas in the swimbladder increased buoyancy of young larvae just after first inflation, our results suggest that active control of the swimbladder may not occur until after the formation of the two chambers and subsequent development and maturation of vasculature, musculature and innervation of these structures at about 28-30 dph.

Alterations of cardiac innervation in evolving myocardial infarction and transplanted hearts. An anatomo-clinical reappraisal.

BACKGROUND: Debate regarding the alterations of the cardiac innervation in an evolving myocardial infarction and transplanted hearts is still raging and most studies are based on radionuclide uptake of neurotransmitters or on the evaluation of the cardiorespiratory reflex. METHODS: The present investigation, upon human autoptic specimens of 57 infarcts and 8 cardiac transplants, was carried out with traditional neuropathology and modern molecular biology techniques. The specimens were selected for the identification of neurons, nerve fibers and their sheaths. RESULTS: First of all, these techniques confirmed the gross difference in the vulnerability of infarcted myocytes if compared with the local innervation, the metabolism of which is infinitely less oxygen-dependent than that of working myocardium (approximate quantitation below). Delicate technicalities of the traditional silver impregnation for nerves usually yield a large incidence of artifacts. Thereby, only perfect results (20% of cases), corroborated by parallel nerve sheath immunostaining (70% of cases), were retained and documented herein. In the meantime, acidosis and free radicals increase, while catabolite accumulation supervenes. These three factors threaten myocardial viability. Thereby, nervelets can be seen to survive the hyperacute phase of ischemia, but may be in part damaged by the successive granulocytic-macrophage inflammation enzyme lysis of the infarcted muscle. The delayed and incomplete anatomical neural damage is confirmed by the observation of preserved nerve sheaths and neural filaments surviving in postinfarction scars, almost devoid of myocardiocytes. CONCLUSIONS: The rich sympatho-vagal cardiac network might further provide alternative bypasses for post-infarct reinnervation. The functional implications of this process remain unclear.

[The sympathetic axons of the nerves of the hand]. / Die sympathischen Fasern der Nerven der Hand--eine immunhistochemische Studie.

PURPOSE: In the hand surgery literature, more and more studies seem to indicate that the number of sympathetic fibers in the median and the ulnar nerves varies. However, there are no studies that confirm this suspicion. METHOD AND MATERIAL: Six hours post mortem samples were taken from the median and ulnar nerves, the superficial branch of the radial nerve, and from all digital nerves (each five females and males, average age 78 years). 13 samples were taken from one hand. To make sympathetic fibers visible, the immunohistochemical staining technique with tyrosinhydroxylase (TH) antibodies was used. Quantitative assessment of the sympathetic axons was made in whole cross-sections of the nerve. Statistical evaluation was performed with Wilcoxon rank-sum tests. RESULTS: The TH-positive axons are arranged in groups and are located in the endoneurium. No isolated sympathetic fibers were found in the peri- and epineurium. TH-positive axons were present on the arterial walls including the smallest arterioles. Proximal to the wrist, the median nerve has more sympathetic fibers than the ulnar nerve. The number, however, of the fibers was the same in each fascicle. A comparison of the digital nerves shows significant differences only between the radial nerve of the thumb and the ulnar nerve of the ring finger and between the radial nerve of the index finger and the ulnar nerve of the little finger. CONCLUSION: Although the median nerve proximal to the wrist has on average 20 fascicles and the ulnar nerve only 14, the number of fibres in each fascicle is the same. Therefore, based on the present study we conclude that there is no significant difference in the sympathetic fiber distribution of the two nerves.

Intrinsic choroidal neurons in the duck eye receive sympathetic input: anatomical evidence for adrenergic modulation of nitrergic functions in the choroid.

Intrinsic choroidal neurons (ICN) in the duck eye form an intramural ganglionic plexus that may subserve complex integrative functions. A key feature of such ganglia is an innervation by sympathetic postganglionic neurons. The present study was thus aimed at determining the sympathetic postganglionic innervation of ICN. Choroids were processed for double immunofluorescence labelling with the following markers: tyrosine-hydroxylase (TH)/nitric oxide synthase (nNOS), TH/galanin (GAL), dopamine-beta-hydroxylase (DBH)/vasoactive intestinal polypeptide (VIP), TH/DBH and DBH/alpha-smooth-muscle actin (alphaSMA), and for triple immunofluorescence labelling with VIP/DBH/TH. Epifluorescence and confocal laser scanning microscopy were used for evaluation. Immunoperoxidase staining for TH or DBH in combination with NADPH-diaphorase histochemistry was applied for electron microscopy. ICN spread over the entire choroid but were concentrated in an equatorial zone passing obliquely from naso-cranial to temporocaudal. More than 80% of nNOS-positive ICN showed close appositions of TH/DBH-immunoreactive varicose nerve fibres at the light-microscopic level, as could be confirmed by confocal laser scanning microscopy. Ultrastructurally, these appositions could be defined as both synapses or close contacts without synaptic specialisation. Vascular and non-vascular smooth muscle fibres also received TH/DBH-immunopositive innervation. Our findings suggest that most ICN receive a sympathetic input that might modulate their nitrergic effects upon vascular and non-vascular smooth muscle fibres in the choroid and that they may have more complex functions than merely being a simple parasympathetic relay.

Neurofilaments are transported rapidly but intermittently in axons: implications for slow axonal transport.

Slow axonal transport conveys cytoskeletal proteins from cell body to axon tip. This transport provides the axon with the architectural elements that are required to generate and maintain its elongate shape and also generates forces within the axon that are necessary for axon growth and navigation. The mechanisms of cytoskeletal transport in axons are unknown. One hypothesis states that cytoskeletal proteins are transported within the axon as polymers. We tested this hypothesis by visualizing individual cytoskeletal polymers in living axons and determining whether they undergo vectorial movement. We focused on neurofilaments in axons of cultured sympathetic neurons because individual neurofilaments in these axons can be visualized by optical microscopy. Cultured sympathetic neurons were infected with recombinant adenovirus containing a construct encoding a fusion protein combining green fluorescent protein (GFP) with the heavy neurofilament protein subunit (NFH). The chimeric GFP-NFH coassembled with endogenous neurofilaments. Time lapse imaging revealed that individual GFP-NFH-labeled neurofilaments undergo vigorous vectorial transport in the axon in both anterograde and retrograde directions but with a strong anterograde bias. NF transport in both directions exhibited a broad spectrum of rates with averages of approximately 0.6-0.7 microm/sec. However, movement was intermittent, with individual neurofilaments pausing during their transit within the axon. Some NFs either moved or paused for the most of the time they were observed, whereas others were intermediate in behavior. On average, neurofilaments spend at most 20% of the time moving and rest of the time paused. These results establish that the slow axonal transport machinery conveys neurofilaments.

Expression of GFR alpha-1, GFR alpha-2, and c-Ret mRNAs in rat adrenal gland.

Glial cell line-derived neurotrophic factor (GDNF), an important factor for developing and lesioned pre- and postganglionic sympathetic neurons, and its congeners signal through a receptor complex consisting of the tyrosine kinase c-Ret and a lipid-anchored alpha receptor (GFR alpha 1-4). Using in situ hybridization we show now that the mRNA for GFR alpha-2 is abundant in the adult rat adrenal medulla and its chromaffin cells. Coexpression of c-Ret and GFR alpha-1 mRNA's is restricted to a scarce subpopulation of medullary sympathetic neurons. Both GFR alpha-1 and GFR alpha-2 mRNA's are associated with preganglionic nerve trunks in the adrenal cortex. It is conceivable therefore that GDNF and related factors may activate chromaffin and preganglionic Schwann cells through a GFR-alpha receptor in absence of c-Ret.

Heme oxygenase and NO-synthase in the human prostate--relation to adrenergic, cholinergic and peptide-containing nerves.

In the human prostate, the distribution of heme oxygenase (HO-1 and HO-2)-, nitric oxide synthase (NOS)-, and tyrosine hydroxylase (TH)-immunoreactive (IR), acetylcholine-esterase (AChE)-positive, and some peptidergic nerve structures was investigated. Cell bodies and nerve fibers within coarse nerve trunks expressed HO-1-, HO-2-, NOS-, TH-, and vasoactive intestinal polypeptide (VIP)-immunoreactivities, and were AChE-positive, but, as revealed by confocal microscopy. HO- and NOS-immunoreactivities were found in separate nerves. Along strains of smooth muscle, intraglandular septa, and around acini, HO-1-, NOS-, and VIP-IR nerves, and AChE-positive fibers were observed. Double immunostaining showed that NOS- and VIP-immunoreactivities were generally co-localized in varicose nerve terminals. Some TH-IR terminals had profiles that were similar, but not identical, to those of NOS-, HO-1-, or VIP-IR terminals. NPY-IR nerves were similarly distributed as VIP- and NOS-IR fibers, and were found in rich amounts. Calcitonin gene-related peptide (CGRP)-IR nerves were few compared to other nerve populations studies. NOS- and CGRP-IR terminals had similar profiles, but the immunoreactivities were not co-localized. Nitric oxide and electrical stimulation of nerves relaxed noradrenaline-contracted preparations of prostatic stroma. Inhibition of synthesis of nitric oxide abolished the electrically induced relaxations. VIP had small relaxant effects, whereas carbon monoxide was without effect on noradrenaline-contracted strips. The innervation pattern and the functional effects suggest that the L-arginine/nitric oxide pathway may have a role in the control of human prostatic smooth muscle activity and/or in secretory neurotransmission. A physiological role of carbon monoxide in the prostate remains to be established.

Ultrastructural localization of sympathetic axons in experimental rat sciatic nerve neuromas.

The ultrastructural localization of sympathetic axons was investigated in normal rat sciatic nerves and experimental sciatic nerve neuromas. The best ultrastructural localization of noradrenaline in the dense-cored vesicles of sympathetic axons was accomplished following pretreatment of rats with nialamide and 5-hydroxy dopamine, followed by fixation according to the modified chromaffin technique of Tranzer and Richards (1976). After such preparation, sympathetic axons containing 5-hydroxy dopamine-labelled dense-cored vesicles could be identified in normal sciatic nerve. Large accumulations of labelled dense-cored vesicles were also found in acute neuromas, up to 1 week after nerve section. Much smaller numbers of dense-cored vesicles could be identified in chronic neuromas from 2 to 3 weeks following nerve section. Sympathetic axons could also be identified following electron probe X-ray microanalysis of the tissue sections, using chromium detection as the marker for the noradrenaline-containing dense-cored vesicles. Unusual configurations of Schwann cell subunits, which enclosed myelinated fibres and sympathetic axon sprouts within the same basal lamina, were identified in the acute neuromas, 3-7 days after nerve section. Such configurations may be of relevance to the pathophysiological interaction which develops between sympathetic efferent and sensory fibres in peripheral nerve neuromas.

[The reaction of the thyroid neural structures in guinea pigs to ionizing radiation exposure]. / Reaktsiia nervnykh struktur shchitovidnoi zhelezy morskikh svinok na vozdeistvie ioniziruiushchei radiatsii.

State and structural organization of the guinea pig thyroid gland were studied histochemically in distanced terms (6 months) after the single external x-ray radiation 12.9 C/kg in doze. with the following intraperitoneal introduction of 131 6.5 C/kg in doze. Atrophically changed zones of parenchyma were observed along with regions of extra- and intrafollicular hyperplasia with compensatory-adaptive manifestations aimed at hormonopoiesis increase. Growth of sympathetic innervation of the vessel walls and around the follicles were found in areas of high functional activity. Direct contact between adrenergic axons and thyrocytes was demonstrated by means of electron microscopy. In parenchyma areas with signs of atrophia, adrenergic nerve fibers and terminals are located only in vessels. Thus, connection between the state of the thyroid gland sympathetic innervation and structural organization of its parenchyma in distanced terms of radiational effects was followed up.

Adrenergic innervation of the human endolymphatic sac.

Adrenergic innervation of the human endolymphatic sac (ES) has not been verified previously. To investigate this question a sensitive histofluorescence method for visualization of catecholamines and serotonin, using a solution composed of sucrose-potassium phosphate-glyoxylic acid (SPG) in cryostat sections, was employed. Three human ES specimens were obtained during surgery for acoustic neuroma. Distinct fluorescence in the subepithelial tissue, indicating the presence of monoaminergic neurones and their axonal varicosities, was observed. SPG-positive terminal nerve fibres around small ES capillaries and subendothelially were also seen. Like the effects of sympathetic stimulation elsewhere in the human body, the ES might respond to such stimulation with, for example, vasoconstriction and increased transepithelial water transport. Since the ES is thought to be responsible for maintaining inner ear fluid homeostasis, adrenergic influence could be important for it to function properly.

The structure, innervation and location of arteriovenous anastomoses in the equine foot.

In the foot of the horse, arteriovenous anastomoses (AVAs) of epithelioid type occurred in the dermis of the coronary band, in the coronary and terminal papillae, in neurovascular bundles and at the entrance to and along the length of the dermal laminae. A particular feature of the epithelioid segment of AVAs in the horse, compared with that of other species, was the height and surface complexity of many of the endothelial cells. They extended into the lumen, forming undercut and tunnel-like areas which correlated with the characteristic surface marking of AVAs observed in vascular casts. The number of cell organelles, including the concentration of vesicles in the luminal cytoplasm, suggested cells with a high metabolic activity. The luminal surface possessed numerous microvilli and long cytoplasmic cell processes which appeared to surround material in the lumen. The innervation of AVAs was more dense than that of the arteries and consisted of adrenergic and peptidergic nerves. Noradrenaline- and neuropeptide Y-containing nerves were identified as the vasoconstrictor components of the nerve supply and occurred along arteries and formed dense plexuses around AVAs. Calcitonin gene-related peptide, substance P and vasoactive intestinal polypeptide are vasodilators and were present in single nerve fibres which accompanied arteries and AVAs along the length of the dermal laminae. In this study the distribution, density and innervation of AVAs in the equine foot are correlated with their proposed role in the development of acute laminitis. The release of vasoactive peptides from diseased organs remote from the foot may induce inappropriate prolonged dilatation of AVAs and thus contribute to the laminar ischaemia of acute laminitis.

Dependence on p75 for innervation of some sympathetic targets.

The low-affinity neurotrophin receptor p75 binds all neurotrophins with similar affinity. For elucidation of its function, mice bearing a null mutation in the p75 locus were generated. Examination of sympathetic innervation of target tissues revealed that pineal glands lacked innervation and sweat gland innervation was absent or reduced in particular footpads. The absence of adult innervation reflects the failure of axons to reach these targets during development rather than a target deficit. These results indicate that p75 facilitates development of specific populations of sympathetic neurons, for which it may support axon growth.

The bovine tubouterine junction: general innervation pattern and distribution of adrenergic, cholinergic, and peptidergic nerve fibers.

The innervation of the bovine tubouterine junction was studied in sexually mature heifers using antisera against various neuronal markers and a modified acetylcholinesterase method. The vast majority of the nerve fibres in the bovine tubouterine junction belongs to the sympathetic nervous system; peptidergic and cholinergic fibers are restricted to characteristic locations. The endosalpinx in the adovarian portion of the terminal tubal segment is poorly innervated. The mucosa of the aduterine portion and of the tubouterine transitional region proper receives a strikingly dense innervation, which is observed mainly in combination with a strong vascularisation of specialised mucosal structures. In the endometrium, perivascular nerves accompany the ascending spiral arteries but sporadic contacts between nerve fibres and uterine glands are also observed. From the muscular coat the inner longitudinal layer of the terminal tubal segment is more richly supplied by nerve fibres than the intermediate circular and outer longitudinal layers of the tubouterine junction. No changes in the innervation pattern were seen during the different stages of the sexual cycle.

Ultrastructural evidence of indirect and direct autonomic innervation of human Leydig cells: comparison of neonatal, childhood and pubertal ages.

Recent physiological studies have indicated an autonomic influence on the secretion of testosterone from Leydig cells in humans and laboratory animals. Furthermore, a few studies have shown enhanced autonomic control of Leydig cell function in immature, relative to mature, laboratory animals. In the current ultrastructural study of the human testicular interstitium the morphology of autonomic components is described from neonatal, childhood and pubertal ages. Autonomic nerve fibers and varicosities with neurotransmitter vesicles are described in proximity to Leydig cells. The observed autonomic terminals are classified by vesicle morphology into three general types: (1) Type I with predominantly small agranular vesicles (30-60 nm) and occasional larger granular vesicles (100 nm). This type is morphologically consistent with being cholinergic. (2) Type II with predominantly small granular vesicles (30-60 nm), as well as sporadic large granular vesicles. These are morphologically consistent with adrenergic terminals. (3) Type III which exhibit numerous large granular vesicles of mixed size. Evidence of autonomic terminals is encountered most frequently in childhood biopsies, age 3 to 10 years. The neonatal specimen (4 months) is noteworthy in that many of the Schwann cells appear immature and no adrenergic terminals are observed. In contrast, terminals morphologically consistent with being adrenergic are common in the childhood series of biopsies. Although the vast majority of the autonomic terminals are associated with Leydig cells indirectly as "boutons en passant", separated by approximately 150 nm to more than a micron, evidence of direct contact (20 nm) of autonomic terminals with Leydig cells is presented.(ABSTRACT TRUNCATED AT 250 WORDS)

The distribution and colocalization of neuropeptides in perivascular nerves innervating the large arteries and veins of the snake, Elaphe obsoleta.

Single- and dual-labelling immunohistochemistry were used to determine the distribution and coexistence of neuropeptides in perivascular nerves of the large arteries and veins of the snake, Elaphe obsoleta, using antibodies for vasoactive intestinal polypeptide, substance P, calcitonin gene-related peptide, neuropeptide Y, galanin, somatostatin, and leu-enkephalin. Blood vessels were sampled from four regions along the body of the snake: region 1, arteries and veins anterior to the heart; region 2, central vasculature 5 cm anterior and 10 cm posterior to the heart; region 3, arteries and veins in a 30-cm region posterior to the liver; and region 4, dorsal aorta and renal arteries, renal and intestinal veins, 5-30 cm cephalad of the vent. A moderate to dense distribution of vasoactive intestinal polypeptide-like immunoreactive fibres was found in most arteries and veins of regions 1-3, but fibres were absent from the vessels of region 4. The majority of vasoactive intestinal polypeptide-like immunoreactive fibres contained colocalized substance P-like immunoreactivity, and these fibres were unaffected by either capsaicin or 6-hydroxydopamine (6-OHDA) pretreatment. In the anterior section of the snake, the vagal trunks contained many cell bodies with colocalized vasoactive intestinal polypeptide and substance P-like immunoreactivity. It is suggested that the vasoactive intestinal polypeptide/substance P-like immunoreactive cell bodies and fibres are parasympathetic postganglionic nerves. Neuropeptide Y-like immunoreactive fibres were observed in all arteries and veins, being most dense in regions 3 and 4. The majority of these fibres also contained colocalized galanin-like immunoreactivity, and were absent in tissues from 6-OHDA pretreated snakes, suggesting that neuropeptide Y and galanin are colocalized in adrenergic nerves. A small number of neuropeptide Y-like immunoreactive fibres contained vasoactive intestinal polypeptide but not galanin, and were unaffected by 6-OHDA treatment. All calcitonin gene-related peptide-like immunoreactive fibres contained colocalized substance P-like immunoreactivity, and these fibres were observed in all vessels, being particularly dense in the carotid artery and jugular veins. All calcitonin gene-related peptide/substance P-like immunoreactive fibres appeared damaged after capsaicin treatment suggesting they represent fibres from afferent sensory neurons. A sparse plexus of somatostatin-like immunoreactive fibres was observed in the vessels only from region 4. No enkephalin-like immunoreactive fibres were found in any blood vessels from any region. This study provides morphological evidence to suggest that there is considerable functional specialization within the components of the rat snake peripheral autonomic system controlling the circulation, in particular the regulation of venous capacitance.

A histofluorescent study of sympathetic innervation of human palatine tonsils.

The glyoxylic catecholaminergic histofluorescence method was employed on human palatine tonsil specimens in order to study the sympathetic innervation present. One percent neutral red was used as a counterstain. Abundant sympathetic fibers were demonstrable around the blood vessels of the medulla and capsule. However, few sympathetic fibers were found around the vessels of the subepithelial connective tissue and interfollicular septa. In the areas of the follicle and extrafollicle where B and T lymphocytes were located, sympathetic fibers were not found. These findings indicate that if sympathetic innervation can affect T and B cells, it will do so indirectly. Results also show that there is a higher norepinephrine content in focally infected tonsils that is not due to hyperactivity of the sympathetic nerve, but may be due to other mechanisms. Finally surgical dissection at the capsule during tonsillectomy will reduce bleeding, perhaps because vessels there have an abundant sympathetic innervation that leads to good vessel contraction.

Organization of medullary adrenergic and noradrenergic projections to the periaqueductal gray matter in the rat.

The periaqueductal or midbrain central gray matter (CG) in the rat contains a dense network of adrenergic and noradrenergic fibers. We examined the origin of this innervation by using retrograde and anterograde axonal tracers combined with immunohistochemistry for the catecholamine biosynthetic enzymes tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT). Following injections of the fluorescent tracers Fast Blue or Fluorogold into the CG, double-labeled neurons in the medulla were identified mainly in the noradrenergic A1 group in the caudal ventrolateral medulla (VLM) and A2 group in the medial part of the nucleus of the solitary tract (NTS); and in the adrenergic C1 group in the rostral ventrolateral medulla and C3 group in the rostral dorsomedial medulla. Injections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into these cell groups resulted in a distinct pattern of axonal labeling in various subdivisions of the CG. Anterogradely labeled fibers originating in the medial NTS were predominantly found in the lateral portion of the dorsal raphe nucleus and in the adjacent part of the lateroventral CG (CGlv). Following PHA-L injections into the C3 region the anterogradely labeled fibers were diffusely distributed in the CGlv and the dorsal raphe nucleus at caudal levels, but rostrally tended to be located laterally in the CGlv. In contrast, ascending fibers from the caudal and rostral VLM terminated in the rostral dorsal part of the CGlv and in the dorsal nucleus of the CG, whereas ventral parts of the CG, including the dorsal raphe nucleus, contained few afferent fibers. Double-label studies with antisera against DBH and PNMT confirmed that noradrenergic neurons in the A1 and A2 groups and adrenergic neurons in the C1 and C3 groups contributed to these innervation patterns in the CGlv. Noradrenergic and adrenergic projections from the medulla to the CG may play an important role in a variety of autonomic, sensory and behavioral processes.

Effect of perivascular sympathectomy on distal adrenergic innervation in the hands of monkeys.

Perivascular sympathectomy has been thought to cause distal adrenergic denervation. We performed perivascular sympathectomy for a distance of 1 cm. on two common digital arteries in the right hands of two anaesthetised Macaca arctoides monkeys. Four days later, samples were taken for glyoxylic acid-induced fluorescence examination of the operated and opposite control hand. The distal adrenergic nerves were morphologically normal in appearance after the perivascular sympathectomy. The operation should perhaps be called adventitectomy rather than perivascular sympathectomy and its positive effects may be due to the loss of adventitial support for the vasospastic arteries rather than adrenergic denervation.