Adrenergic Modulation of Hematopoiesis.

Hematopoiesis produce every day billions of blood cells and takes place in the bone marrow (BM) by the proliferation and differentiation of hematopoietic stem cells (HSC). HSC are found mainly adjacent to the BM vascular sinusoids where endothelial cells and mesenchimal stromal cells promote HSC maintenance by producing a variety of factors. Other cell types that regulate HSC niches include sympathetic nerves, non-myelinating Schwann cells and a variety of mature hematopoietic cells such as macrophages, neutrophils, and megakaryocytes. This review will focus on the role of adrenergic signals, i.e. of catecholamines, in the regulation of the HSC niche. The available evidence is rather controversial possibly due to the fact that adrenergic receptors are expressed by many cellular components of the niche and also by the often neglected observation that catecholamines may be produced and released also by the BM cells themselves. In addition one has to consider that, physiologically, the sympathetic nervous system (SNS) activity follows a circadian rhythmicity as driven by the suprachiasmatic nucleus (SCN) of the hypothalamus but may be also activated by cognitive and non-cognitive environmental stimuli. The adrenergic modulation of hematopoiesis holds a considerable potential for pharmacological therapeutic approaches in a variety of hematopoietic disorders and for HSC transplantation however the complexity of the system demands further studies. Graphical Abstract Sympathetic nerve termini may release NE while mature BM cells may release norepinephrine (NE) and / or epinephrine (E). Both may bind to ß-adrenergic receptor (AR) expressed in nestin+MSC in the hematopoietic stem cell (HSC) niche and regulate the physiological trafficking of HSC by modulating the expression of CXCL12 and SCF. Both NE and E may also activate Lin - c-Kit+ Sca-1+ (LKS) cell via another AR. In addition, NE may also signal to α1-AR expressed in pre-B cells which by TGF-ß secretion might regulate proliferation of their lymphoid progenitors in an autocrine manner and/or inhibit myeloid progenitors.

Circadian clock-dependent increase in salivary IgA secretion modulated by sympathetic receptor activation in mice.

The salivary gland is rhythmically controlled by sympathetic nerve activation from the suprachiasmatic nucleus (SCN), which functions as the main oscillator of circadian rhythms. In humans, salivary IgA concentrations reflect circadian rhythmicity, which peak during sleep. However, the mechanisms controlling this rhythmicity are not well understood. Therefore, we examined whether the timing of parasympathetic (pilocarpine) or sympathetic (norepinephrine; NE) activation affects IgA secretion in the saliva. The concentrations of saliva IgA modulated by pilocarpine activation or by a combination of pilocarpine and NE activation were the highest in the middle of the light period, independent of saliva flow rate. The circadian rhythm of IgA secretion was weakened by an SCN lesion and Clock gene mutation, suggesting the importance of the SCN and Clock gene on this rhythm. Adrenoceptor antagonists blocked both NE- and pilocarpine-induced basal secretion of IgA. Dimeric IgA binds to the polymeric immunoglobulin receptor (pIgR) on the basolateral surface of epithelial cells and forms the IgA-pIgR complex. The circadian rhythm of Pigr abundance peaked during the light period, suggesting pIgR expression upon rhythmic secretion of IgA. We speculate that activation of sympathetic nerves during sleep may protect from bacterial access to the epithelial surface through enhanced secretion of IgA.

Mimicking disruption of brain-immune system-joint communication results in collagen type II-induced arthritis in non-susceptible PVG rats.

The brain-immune system-joint communication is disrupted during collagen type II (CII) arthritis in DA rats. Since PVG rats are not susceptible to arthritis induction, comparison of hypothalamic and peripheral neuro-endocrine and immune responses between immunized DA and PVG rats might help to explain their different susceptibility to develop the disease. PVG and DA rats were immunized with CII. Corticosterone, neurotransmitters, anti-CII antibodies, and cytokine concentrations in plasma, and hypothalamic neurotransmitters and cytokines were determined by ELISA, Luminex, HPLC and RT-qPCR. Adrenalectomy or sham-operation was performed in PVG and DA rats 14 days before immunization. Basal plasma corticosterone and adrenaline concentrations were significantly higher, and plasma cytokines and hypothalamic noradrenaline were lower in PVG rats than in DA rats. While DA rats developed severe arthritis upon immunization (maximum score 16), only 12 out of 28 PVG rats showed minimal symptoms (score 1-2). The density of sympathetic nerve fibers in arthritic joints of DA rats markedly decreased, but it remained stable in immunized PVG rats. The ratio corticosterone to IL-1ß levels in plasma was markedly higher in immunized PVG rats than in arthritic DA rats. Adrenalectomy resulted in severe arthritis in PVG rats upon immunization with CII. While DA rats show an altered immune-brain communication that favors the development of arthritis, PVG rats express a protective neuro-endocrine milieu, particularly linked to the basal tone of the HPA axis. Mimicking disruption of this axis elicits arthritis in non-susceptible PVG rats.

Adrenergic nerves govern circadian leukocyte recruitment to tissues.

The multistep sequence leading to leukocyte migration is thought to be locally regulated at the inflammatory site. Here, we show that broad systemic programs involving long-range signals from the sympathetic nervous system (SNS) delivered by adrenergic nerves regulate rhythmic recruitment of leukocytes in tissues. Constitutive leukocyte adhesion and migration in murine bone marrow (BM) and skeletal-muscle microvasculature fluctuated with circadian peak values at night. Migratory oscillations, altered by experimental jet lag, were implemented by perivascular SNS fibers acting on ß-adrenoreceptors expressed on nonhematopoietic cells and leading to tissue-specific, differential circadian oscillations in the expression of endothelial cell adhesion molecules and chemokines. We showed that these rhythms have physiological consequences through alteration of hematopoietic cell recruitment and overall survival in models of septic shock, sickle cell vaso-occlusion, and BM transplantation. These data provide unique insights in the leukocyte adhesion cascade and the potential for time-based therapeutics for transplantation and inflammatory diseases.

Adrenoreceptor-coupled signal-transduction mechanisms mediating lymphocyte apoptosis induced by endogenous catecholamines.

Our previous work has shown that lymphocytes synthesize catecholamines (CAs) and the endogenous CAs accelerate apoptosis of concanavalin A (Con A)-activated lymphocyte. Here, we explored the involvement of adrenoreceptors (ARs) and signal molecules coupled to the ARs in the endogenous CA-mediated modulation of lymphocyte apoptosis. Pargyline, an inhibitor of CA degradation, up-regulated the expression of cleaved caspase-3 protein and increased the number of apoptotic cells. Antagonists of alpha(1)-ARs and beta(2)-ARs, not antagonists of alpha(2)-ARs or beta(1)-ARs, blocked these effects of pargyline. The facilitating effects of pargyline on lymphocyte apoptosis were mimicked by activators of adenylate cyclase and PKC, but reversed by inhibitors of PKA, PLC and PKC. Pargyline-stimulated CREB activation and Smac/DIABLO expression were prevented by the inhibitors of PKA, PLC and PKC. These results imply that endogenous CA-induced lymphocyte apoptosis is mediated by cAMP-PKA- and PLC-PKC-linked CREB-Smac/DIABLO pathways coupled with alpha(1)-ARs and beta(2)-ARs.

Disrupted brain-immune system-joint communication during experimental arthritis.

OBJECTIVE: To explore the hypothesis that, in parallel with alterations in the hypothalamus-pituitary-adrenal axis and the sympathetic nervous system, hypothalamic cytokine expression and monoaminergic neurotransmitter concentrations are affected during the course of arthritis development induced by type II collagen. This hypothesis was based on evidence that acute inflammatory processes induce cytokine expression in the brain and affect neuronal activity. We also studied whether depletion of hypothalamic noradrenaline can affect peripheral joint disease. METHODS: Hypothalamic cytokine gene expression and neurotransmitter concentration, parameters of inflammation, and joint innervation were evaluated during arthritis development in rats induced by injection of type II collagen in Freund's incomplete adjuvant. Noradrenergic neurons in the brain were depleted with 6-hydroxydopamine. RESULTS: Transiently increased corticosterone levels, followed by increased adrenaline levels and hypothalamic interleukin-1beta (IL-1beta) and IL-6 overexpression were observed only during the induction phase of the disease. Hypothalamic noradrenaline content was increased during the symptomatic phase and was paralleled by a gradual loss of noradrenergic fibers in the joints. The positive correlation between hypothalamic IL-1beta expression and noradrenaline content in control groups was not observed in rats in which arthritis developed. Depletion of hypothalamic noradrenergic neurons when arthritis was established did not affect the course of the disease. CONCLUSION: The dissociation between hypothalamic cytokine gene expression and noradrenergic neuronal activity, the lack of sustained stimulation of the stress axes, and the loss of sympathetic signals in the joints indicate a disruption in communication between afferent immune messages to the central nervous system and 2 main efferent antiinflammatory pathways under control of the brain during collagen-induced arthritis.

Angiotensin II type 1 receptors may not influence response of spinal autonomic neurons to axonal damage.

OBJECTIVES: Angiotensin II can promote cell stress, and the expression of its AT1 receptor is characteristic of neuronal populations that die off in multiple systems atrophy and Parkinson's disease. To explore the possible significance of these facts, we undertook to: (1) clarify the distribution of AT(1) in rat neurons; (2) use selective antagonists as a means of determining whether AT1 activation predisposes stressed neurons to die. METHODS: AT1-expression was examined by immunohistochemistry and by autoradiography for [125I]-sarcosine1-angiotensin II binding in sensory, motor and autonomic neurons. To induce cell loss in a specific neuronal population, rats were given systemic i.v. injection of anti-acetylcholinesterase antibodies, which cause a delayed death of pre-ganglionic sympathetic neurons in the intermediolateral nucleus (IML). As pharmacologic intervention, some immunolesioned rats were treated with the selective AT1 antagonist, Candesartan. RESULTS: Immunohistochemistry and autoradiography revealed AT1 expression in dorsal root ganglia, superior cervical ganglion. In the dorsal horn of the spinal cord, AT1 immunostainining and angiotensin binding were both prominent. In ventral horn and IML, immunoreactivity for AT1 and choline acetyltransferase co-localized in pre-ganglionic sympathetic and somatic motor neurons. Immunolesion caused over 50% loss of IML perikarya within 3 months. Concurrent treatment with the AT1 antagonist, Candesartan, did not affect the outcome. DISCUSSION: AT1 expression is surprisingly widespread in sensory, autonomic and somatic motor neurons of the rat. This expression may be important to the normal physiology of these systems. Present data, however, do not support the concept that AT1 activation contributes to the loss of autonomic neurons after axonal damage.

Roles of alpha-adrenoceptors and sympathetic nerve in acute herpetic pain induced by herpes simplex virus inoculation in mice.

Percutaneous inoculation with herpes simplex virus type-1 brings about herpes zoster-like skin lesions, tactile allodynia, and mechanical hyperalgesia in mice. This study was conducted to determine whether the sympathetic nervous system and alpha-adrenoceptors would be involved in these pain-related responses and whether the alpha(2)-adrenoceptor agonist clonidine would suppress these responses. The adrenergic neuron blocker guanethidine and the non-selective alpha-adrenoceptor antagonist phentolamine did not affect the pain-related responses, although these agents suppressed the pain-related responses induced by partial ligation of the sciatic nerve. The pain-related responses induced by herpetic inoculation was suppressed by intraperitoneal and intrathecal injections, but not by intraplantar and intracerebroventricular injections, of clonidine. The suppressive effect of an intraperitoneal injection of clonidine (0.1 mg/kg) was antagonized by intrathecal injections of phentolamine and the alpha(2)-adrenoceptor antagonist yohimbine, but not the alpha(1)-adrenoceptor antagonist prazosin. The results suggest that sympathetic nerves and alpha-adrenoceptors are not involved in the pain-related responses induced by herpetic infection. Clonidine suppresses the responses probably through the action on alpha(2)-adrenoceptors in the dorsal horn.

Xanthine oxidase, but not neutrophils, contributes to activation of cardiac sympathetic afferents during myocardial ischaemia in cats.

Activation of cardiac sympathetic afferents during myocardial ischaemia causes angina and induces important cardiovascular reflex responses. Reactive oxygen species (ROS) are important chemical stimuli of cardiac afferents during and after ischaemia. Iron-catalysed Fenton chemistry constitutes one mechanism of production of hydroxyl radicals. Another potential source of these species is xanthine oxidase-catalysed oxidation of purines. Polymorphonuclear leukocytes (PMNs) also contribute to the production of ROS in some conditions. The present study tested the hypothesis that both xanthine oxidase-catalysed oxidation of purines and neutrophils provide a source of ROS sufficient to activate cardiac afferents during ischaemia. We recorded single-unit activity of cardiac afferents innervating the ventricles recorded from the left thoracic sympathetic chain (T1-5) of anaesthetized cats to identify the afferents' responses to ischaemia. The role of xanthine oxidase in activation of these afferents was determined by infusion of oxypurinol (10 mg kg(-1), I.V.), an inhibitor of xanthine oxidase. The importance of neutrophils as a potential source of ROS in the activation of cardiac afferents during ischaemia was assessed by the infusion of a polyclonal antibody (3 mg ml(-1) kg(-1), I.V.) raised in rabbits immunized with cat PMNs. This antibody decreased the number of circulating PMNs and, to a smaller extent, platelets. Since previous data suggest that platelets release serotonin (5-HT), which activates cardiac afferents through a serotonin receptor (subtype 3,5-HT3 receptor) mechanism, before treatment with the antibody in another group, we blocked 5-HT3 receptors on sensory nerve endings with tropisetron (300 microg kg(-1), I.V.). We observed that oxypurinol significantly decreased the activity of cardiac afferents during myocardial ischaemia from 1.5 +/- 0.4 to 0.8 +/- 0.4 impulses s(-1). Similarly, the polyclonal antibody significantly reduced the discharge frequency of ischaemically sensitive cardiac afferents from 2.5 +/- 0.7 to 1.1 +/- 0.4 impulses s(-1). However, pre-blockade of 5-HT3 receptors eliminated the influence of the antibody on discharge activity of the afferents during ischaemia. This study demonstrates that ROS generated from the oxidation of purines contribute to the stimulation of ischaemically sensitive cardiac sympathetic afferents, whereas PMNs do not play a major role in this process.

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.

Expression of CD44 and its isoforms in the fetal neuroblasts.

CD44 is a polymorphic transmembrane glycoprotein that exists as multiple isoforms resulting from alternative splicing and posttranslational modifications. Enhanced expression of CD44 has been correlated to the tumorigenicity and metastatic behavior in different malignant tumors. In contrast, human neuroblastomas exhibit an inverse correlation between CD44 expression and tumor malignancy. To determine whether there is a CD44 silencing in sympatho-adrenal precursors as a possible explanation for the down-regulation of CD44 in neuroblastomas, the expression of standard CD44H and v6, v7, v7v8, or v10 isoforms was analyzed by immunohistochemistry in human adrenal glands of 14- to 20-week-old gestational age fetuses. All of the fetal neuroblasts localized in the adrenal gland parenchyma and migrating from the sympathetic nerve chain into the fetal adrenal cortex strongly expressed CD44H but none of the CD44 isoforms could be detected in these cells. In contrast, a strong expression of CD44v7 and v6 was detected in the fetal adrenal cells. These results indicate that, as for many other cell types, the CD44H expressed by fetal neuroblasts may contribute to controlling their migration into the adrenal medulla and that the down-regulation of CD44H in neuroblastoma cells should be explained by mechanisms other than the fetal suppression of CD44H expression in their normal counterparts.

Restoration of splenic noradrenergic nerve fibers and immune reactivity in old F344 rats: a comparison between L-deprenyl and L-desmethyldeprenyl.

L-deprenyl, a monoamine oxidase-B inhibitor, partially reversed the age-associated decline in splenic sympathetic noradrenergic (NA) innervation and immune reactivity in old male rats. The purpose of the present study was to examine whether the effects of deprenyl on splenic sympathetic NA nerve fibers and immune functions are mediated through a metabolite of deprenyl, L-desmethyldeprenyl. Old male F344 rats were treated with 0, 0.25, or 1.0 mg L-(-)-deprenyl/kg BW; 0.025, 0.25, or 1.0 mg L-(-)-desmethyldeprenyl/kg BW; and 1.0 mg D-(+)-desmethyldeprenyl/kg BW i.p. daily for 8 weeks. The animals were sacrificed after a 10-day drug wash-out period and the spleens were removed for histofluorescence, immunocytochemistry, neurochemical, and immunological analysis. The volume density of NA nerve fibers was increased in the spleens of deprenyl- and L-desmethyldeprenyl-treated old rats. Con A-induced IFN-gamma production by spleen cells was elevated in 1.0 mg/kg deprenyl- and L-desmethyldeprenyl-treated rats in comparison to saline- and D-desmethyldeprenyl-treated old rats. Deprenyl and desmethyldeprenyl treatment did not alter the percentage of CD5+ T cells, but treatment with 1.0 mg/kg deprenyl and 0.025 mg/kg L-desmethyldeprenyl prevented the decline in the percentage of sIgM(+)B cells in the spleens of old rats. These results suggest that L-desmethyldeprenyl may be as equipotent as deprenyl in preventing age-associated diminution in splenic sympathetic NA innervation and immunocompetence.

Effects of L-deprenyl treatment on noradrenergic innervation and immune reactivity in lymphoid organs of young F344 rats.

Sympathetic noradrenergic (NA) neuronal activities in the thymus, spleen and mesenteric lymph nodes (MLN) and immune responses in the spleen were examined in young male F344 rats treated daily with 0, 0.25 mg, or 2.5 mg/kg body weight of L-deprenyl, an irreversible monoamine oxidase-B (MAO-B) inhibitor. Rats were treated daily for 1, 15, or 30 days, and sacrificed 7 days after the last deprenyl treatment. Deprenyl treatment increased norepinephrine (NE) content in the spleen without modifying the pattern and density of NA innervation in the splenic white pulp. The concentration of NE was unaltered in the thymus, but it was increased in the MLN of deprenyl-treated rats. One day of treatment with deprenyl decreased splenic NK cell activity while 15 days of deprenyl treatment enhanced splenic NK cell activity. Deprenyl elevated Con A-induced T lymphocyte proliferation following 30 days of treatment, but did not alter spleen cell Con A-induced IL-2 production or the percentage of CD5 + T cells in the spleen. A moderate decrease in the percentage of sIgM + B cells was observed in the spleens of 15- and 30-day deprenyl-treated rats. These results suggest that deprenyl has sympathomimetic action on sympathetic NA nerve fibers in the spleen; the enhancement of NA neuronal activity may contribute to the modulation of immune responses in the spleen.

Tyrosine hydroxylase- and nitric oxide synthase-immunoreactive nerve fibers in mitral valve of young adult and aged Fischer 344 rats.

Using confocal fluorescence microscopy we studied, in whole mounts of heart mitral valves of young adult and aged Fischer 344 rats, the distribution of nerves containing the catecholamine marker tyrosine hydroxylase (TH) or the synthetic enzyme marker for nitric oxide, nitric oxide synthase (NOS). TH-IR was localized in two separate nerve plexuses which do not intermingle. The 'major' plexus arose from the annulus region, traversed the basal zone of the valve, and ramified in the intermediate zone to form a dense network of fine fibers. The 'minor' plexus was restricted to the distal zone and originated from bundles that ascended the chordae tendineae to enter the valve cusp. A concentric zone located between the major and minor plexuses was devoid of TH-IR nerve fibers. Both plexuses demonstrated (i) nerves that contained numerous varicosities along the length of each fiber, (ii) many terminal axons and (iii) different shaped terminal axon endings. With age, the density of TH-IR innervation in the mitral valve was markedly reduced; and nerve fibers of the minor plexus were limited to the chordae tendinae, without extending into the valve cusp itself. NOS-IR fibers in the mitral valve formed a loose network that extended from the annulus to more than halfway down the cusp. The varicose beads of the terminal NOS-IR axons appeared to become progressively smaller and less intensely fluorescent until they disappeared at the terminal endings, which showed no specializations. No NOS-IR fibers were observed in the distal zone of the valve leaflet or in the chordae. In the aged mitral valve, the density of NOS-IR nerves was decreased, as compared with NOS-IR innervation in the young adult valve. The existence of TH and NOS as well as other signal molecule markers in heart valve nerves and the disparate patterns of their distribution and localization provide evidence supporting the theory that heart valve nerves form a complex reflexogenic control system in the mitral heart valve. In summary, two distinct neural architectures are described for TH-IR and NOS-IR valve nerves, respectively. The former are believed to be axons dedicated to sympathetic motor functions. The NOS-IR valve nerves may have sensory and/or postganglionic parasympathetic motor functions. An implication of these findings is that different, but perhaps related, valve functions may be mediated by separate, dedicated circuits.

Noradrenergic system in the chicken brain: immunocytochemical study with antibodies to noradrenaline and dopamine-beta-hydroxylase.

A light microscopic immunocytochemical study, using antisera against noradrenaline (NA) and dopamine-beta-hydroxylase (DBH), revealed the noradrenergic system in the brain of the chicken (Gallus domesticus). NA- and DBH-immunoreactive (ir) elements showed a similar distribution throughout the whole brain. The neurons immunoreactive for the monoamine were confined to the lower brainstem, the pons, and the medulla. In the pons, a rather dense group of cells was found in the dorsal, most posterior part of the locus coeruleus and in the caudal nucleus subcoeruleus ventralis. A few labeled cells appeared in and around the nucleus olivaris superior in the most caudal part of the metencephalic tegmentum. In the medulla oblongata, noradrenergic cells could be visualized at the level of the nucleus of the solitary tract and in a ventrolateral complex. Virtually all regions of the brain contained a rather dense innervation by NA- and DBH-immunopositive varicose fibers. Noradrenergic fibers and terminals were especially abundant in the ventral forebrain and in the periventricular hypothalamic regions. DBH-ir and NA-ir fibers, varicosities, and punctate structures could be observed in close association with immunonegative perikarya in several brain regions, more specifically in the ventral telencephalon, in the mid- and tuberal hypothalamic region, and in the dorsal rostral pons. Some perikarya in these brain areas were completely surrounded by noradrenergic structures that formed pericellular arrangements around the cells. The present study on the distribution of the noradrenergic system in the brain of the chicken combined with the results of a previous report on the distribution of L-Dopa and dopamine in the same species (L. Moons, J. van Gils, E. Ghijsels, and F. Vandesande, 1994, J. Comp. Neurol. 346:97-118) offers the opportunity to differentiate between the various catecholamines in the brain of this vertebrate. The results are discussed in relation to catecholaminergic systems previously reported in avian species and in the mammalian brain.

Immunohistochemical localization of tyrosine hydroxylase in corneal nerves.

The sympathetic innervation of the mammalian cornea is thought to play an important role in the regulation of epithelial ion transport, mitogenesis, and wound healing following corneal injuries. Anatomically, the three-dimensional organization and relative density of corneal sympathetic innervation in many species remains inadequately described. In the present study, the sympathetic innervation of five different mammals (guinea pig, rat, mouse, hamster, and human) was studied in corneas sectioned parallel to the main axis of fiber orientation by labeling the fibers immunohistochemically with antiserum against tyrosine hydroxylase and an avidin-biotin-diaminobenzidine technique. The results showed that each species displayed a distinctive pattern and density of tyrosine hydroxylase immunoreactive (TH-IR) corneal innervation that was unique to that species. The overall level of TH-IR innervation was highest in the guinea pig, moderate in the human, hamster, and rat, and lowest in the mouse. In all species examined, TH-IR nerves were most numerous in the corneoscleral limbus where they either formed intimate associations with blood vessels or coursed through the connective tissue matrix apparently unrelated to vascular elements. Other TH-IR nerves entered the cornea proper in radially directed stromal nerve bundles to give rise to subepithelial plexuses of varying complexity. Occasional intraepithelial penetrations were observed in the guinea pig, human, and rat. Removal of the superior cervical ganglion resulted in the total loss of TH-IR staining from guinea pig and hamster corneas and in the substantial but incomplete loss of TH-IR staining from rat and mouse corneas, thus demonstrating their predominantly sympathetic origin. Combined sympathetic and sensory ocular denervation in the rat eliminated almost all corneal and limbal TH-IR immunostaining, thus suggesting a minor TH-IR sensory component in this species. In agreement with this conclusion, small numbers of TH-IR sensory neurons and an abundance of TH-IR fibers were observed in the trigeminal ganglia of the rat and guinea pig. Removal of the rat main ciliary ganglion resulted in the loss of additional TH-IR fibers from the chamber angle and iris, thereby confirming a partial parasympathetic contribution to the rat iridial TH-IR innervation. Following unilateral removal of the superior cervical ganglion in rats and guinea pigs, the contralateral cornea contained increased numbers of TH-IR nerves, suggesting an upregulation of tyrosine hydroxylase (TH) expression in some contralateral axons.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of cell surface antigens on the adrenergic neuroblastoma clone A2(1).

Neuroblastoma cell lines have been extensively used to identify the presence of brain reactive autoantibodies in the sera of patients with systemic lupus erythematosus (SLE) who have neuropsychiatric involvement and in the animal models (murine) of this disorder. In this study, a characterization of murine neuroblastoma cell surface antigens, from the adrenergic A2(1) cell line, have indicated both similarities and differences with the cell surface antigens of normal mouse brain. It has also shown that some of these antigens are nervous system specific, whereas others are not. These data indicate that a more precise definition of the antigens on the surface of neuroblastoma cells, with which anti-brain autoantibodies react, is necessary for an understanding of the neuropsychiatric manifestations associated with autoimmune diseases such as SLE.

Organization of the guinea-pig uterine innervation. Distribution of immunoreactivities for different neuronal markers. Effects of chemical- and pregnancy-induced sympathectomy.

The structural organization of the guinea-pig uterine innervation was investigated by an immunofluorescence method using neurofibrillary protein (NF) and neuron-specific enolase (NSE) as general neuronal markers. NF- and NSE-immunoreactive nerve trunks and non-varicose nerves formed continuous networks similar to nerves with analogue morphology and with immunoreactivities for tyrosine hydroxylase (TH; adrenergic nerves) and neuropeptide Y (NPY). NF- and NSE-immunoreactive non-varicose nerves occurred in the myometrium and along vessels, where TH- and NPY-immunoreactive varicose nerves were also comparatively frequent. After chemical sympathectomy all TH- and NPY-immunoreactive varicose nerves and most NF- and NSE-immunoreactive non-varicose nerves disappeared, suggesting colocalization of TH, NPY, NF and NSE immunoreactivities. During pregnancy all NF-, NSE-, TH- and NPY-immunoreactive nerve structures disappeared in the foetus-bearing uterine horns whereas in the cervix and non-foetus-bearing uterine horns only the myometrial TH- and NPY-immunoreactive varicose nerves disappeared. After parturition there was a complete structural restoration of all types of immunoreactive nerves in previously non-foetus-related tissue. The reinnervation of this tissue followed a similar time-course to that after chemical sympathectomy. In contrast, the reinnervation of previously foetus-related tissue was much slower and incomplete. In conclusion, the whole autonomic uterine innervation undergoes overt structural changes during pregnancy and these changes are related to the foetus-bearing regions.

Immunosympathectomy: lack of evidence for a complement-mediated cytotoxic mechanism.

To determine whether the destruction of peripheral sympathetic neurons by anti-NGF-antibodies results from a complement-mediated cytotoxic action or from the deprivation of endogenous NGF or immunologically NGF-like cross-reacting molecules we investigated the time-course of the reversibility of the effect of NGF-antibodies by neutralizing doses of NGF, together with the effect of NGF-antibodies in complement-deficient mice. After administration of a single dose of 50 mg/kg of purified antibodies to newborn rats the TH level was reduced to 75% of controls after 12 h, to 48% after 24 h, 39% after 36, and 28% after 48 h. After this time no further reduction occurred and levels remained constant up to 14 days. The effect of the NGF-antibodies was reversible on addition of NGF up to 48 h after antibody administration. Although the reversibility was not complete (85% of controls) the extent of the reversibility was the same whether NGF was given 12 or 48 h after the antibodies. The incompleteness of the reversibility is reflected by the small number of degenerating neurons apparent as early as 12 h after antibody administration. Since these early degenerative effects were also seen in complement-deficient mice it is concluded that they involve a small population of neurons, sensitive to short-term NGF deprivation whereas the majority of the neurons can withstand deprivation for up to 48 h without sustaining irreversible damage.