Individually tailored treatment with epirubicin and paclitaxel with or without capecitabine as first-line chemotherapy in metastatic breast cancer: a randomized multicenter trial.

Anthracyclines and taxanes are active cytotoxic drugs in the treatment of early metastatic breast cancer. It is yet unclear whether addition of capecitabine to the combination of these drugs improves the treatment outcome. Patients with advanced breast cancer were randomized to first-line chemotherapy with a combination of epirubicin (Farmorubicin(®)) and paclitaxel (Taxol(®)) alone (ET) or in combination with capecitabine (Xeloda(®), TEX). Starting doses for ET were epirubicin 75 mg/m(2) plus paclitaxel 175 mg/m(2), and for TEX epirubicin 75 mg/m(2), paclitaxel 155 mg/m(2), and capecitabine 825 mg/m(2) BID for 14 days. Subsequently, doses were tailored related to side effects. Primary endpoint was progression-free survival (PFS); secondary endpoints were overall survival (OS), time to treatment failure (TTF), objective response (OR), safety and quality of life (QoL). 287 patients were randomized, 143 to ET and 144 to TEX. Median PFS was 10.8 months for patients treated with ET, and 12.4 months for those treated with TEX (HR 0.84, 95% CI 0.65-1.07, P = 0.16); median OS was 26.0 months for women in the ET versus 29.7 months in the TEX arm (HR 0.84, 95% CI 0.63-1.11, P = 0.22). OR was achieved in 44.8% (ET) and 54.2% (TEX), respectively (χ(2) 3.66, P = 0.16). TTF was significantly longer for patients treated with TEX, 6.0 months, versus 5.2 months following ET (HR 0.73, 95% CI 0.58-0.93, P = 0.009). Severe hematological side effects related to epirubicin and paclitaxel were evenly distributed between the treatment arms, mucositis, diarrhea, and Hand-Foot syndrome were significantly more frequent in the TEX arm. Toxicity-adjusted treatment with ET and TEX showed similar efficacy in terms of PFS, OS, and OR. In this trial with limited power, the addition of capecitabine to epirubicin and paclitaxel as first-line treatment did not translate into clinically relevant improvement of the outcome.

A study of the extrinsic innervation of the guinea pig pylorus with the horseradish peroxidase tracing technique.

The extrinsic innervation of the guinea pig pylorus was studied by the use of the horseradish peroxidase (HRP) tracing technique. Forty-eight hours after injection of HRP into the pyloric sphincter labeled neurons of varying sizes were found throughout the rostrocaudal extent of the dorsal motor nuclei of the vagus. No HRP positive cells were seen in the medial solitary nuclei or the ambiguous nuclei. Many HRP-positive cells were observed in the celiac-superior mesenteric ganglion complex. Occasional cells in the superior cervical and stellate ganglia were also labeled. When the vagal ganglia were analyzed many enzyme-containing cells were found in the nodose ganglia and some cells in the jugular ganglia. Furthermore, about 15-20% of the labeled afferent neurons were located in dorsal root ganglia on both sides, with the majority of cells at the T5--T10 levels. The results are discussed in relation to recent transmitter histochemical findings as well as possible functional roles of the neurons.

Overexpression of c-erbB-2 is related to a higher expression of vascular endothelial growth factor (VEGF) and constitutes an independent prognostic factor in primary node-positive breast cancer after adjuvant systemic treatment.

The aim of this study was to investigate possible associations between the expression of c-erbB-2 and the angiogenic factors vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), p53 status, routine breast cancer prognostic factors and survival. Expression of c-erbB-2, VEGF, bFGF, and p53 protein was determined with an enzyme-linked immunosorbent assay (ELISA) in 656 patients with primary breast cancer (median follow-up time of 83 months). In 60 cases, we also used immunohistochemistry (IHC) for c-erbB-2 evaluation, to be used as a reference for the ELISA. Overexpression of c-erbB-2 was significantly related to a higher expression of VEGF, lower bFGF content, negative steroid receptor status, and a high S-phase fraction. In multivariate analysis, c-erbB-2 was an independent prognostic factor for relapse-free survival (RFS) and overall survival (OS) in all patients, and in node-positive patients, irrespective of the adjuvant systemic therapy. Combined survival analyses regarding c-erbB-2 and VEGF yielded additional prognostic information.

Distribution and origin of peptide-containing nerve fibers in the celiac superior mesenteric ganglion of the guinea-pig.

The origin of the peptidergic nerve fibers and terminals in the celiac superior mesenteric ganglion of the guinea-pig was studied. The distribution of immunoreactivity to enkephalin, substance P, calcitonin gene-related peptide, cholecystokinin, vasoactive intestinal polypeptide/peptide histidine isoleucine, bombesin and dynorphin was analysed in intact animals and in animals subjected to various denervation and ligation procedures. The present results show that each of the connected nerve trunks carries peptidergic pathways and contributes to the peptidergic networks in the celiac superior mesenteric ganglion. Thus, the thoracic splanchnic nerves contain enkephalin-, substance P- and calcitonin gene-related peptide-immunoreactivity of which substance P and calcitonin gene-related peptide coexist in the same nerve fibers. In addition, cholecystokinin-, vasoactive intestinal polypeptide/peptide histidine isoleucine- and dynorphin-immunoreactivity is present in some fibers. All of these immunoreactivities are present in sensory neurons except enkephalin which probably originates in the spinal cord. The mesenteric nerves carry enkephalin-, calcitonin gene-related peptide-, cholecystokinin-, vasoactive intestinal polypeptide/peptide histidine isoleucine-, bombesin- and dynorphin-immunoreactive fibers from the intestine and are the main source for cholecystokinin, vasoactive intestinal polypeptide/peptide histidine isoleucine, bombesin and dynorphin fibers. Double-staining experiments indicate that many of these peptides are synthesized in the same enteric neurons. Also the intermesenteric nerve contains peptide-immunoreactive fibers to the celiac superior mesenteric ganglion from different sources, probably including the distal colon as well as dorsal root ganglia and spinal cord at lower thoracic and lumbar levels. The results are discussed in relation to earlier morphological and physiological studies supporting the view of a role of the celiac superior mesenteric ganglion in local reflex mechanisms involved in regulation of gastrointestinal functions.

Peptide-immunoreactive neurons and nerve fibres in lumbosacral sympathetic ganglia: selective elimination of a pathway-specific expression of immunoreactivities following sciatic nerve resection in kittens.

The distributions of peptide-immunoreactive nerve fibres and cell bodies in lumbosacral paravertebral sympathetic ganglia of young cats were analysed with antibodies to calcitonin gene-related peptide, enkephalin, neurotensin, somatostatin, substance P, galanin, neuropeptide Y and vasoactive intestinal polypeptide. Fairly dense networks of nerve fibres showing enkephalin-, neurotensin-, somatostatin- or substance P-like immunoreactivity were observed in the ganglia. Double-staining experiments revealed that enkephalin- and somatostatin-immunoreactive nerve fibres preferentially surrounded calcitonin gene-related peptide- and/or vasoactive intestinal polypeptide-immunoreactive cell bodies. Neurotensin- and substance P-immunoreactive nerve fibres were mainly associated with neurons showing neuropeptide Y and/or galanin-like immunoreactivity. Occasional nerves containing calcitonin gene-related peptide-, galanin-, neuropeptide Y- or vasoactive intestinal polypeptide-like immunoreactivity were observed. These fibres did not seem to have any direct regional distribution within the ganglia. In kittens surviving for three months after early postnatal sciatic nerve resection, no calcitonin gene-related peptide-immunoreactive cell bodies could be detected in ganglia ipsilateral to the operation. In contrast, vasoactive intestinal polypeptide-like immunoreactivity, which partly co-exists with calcitonin gene-related peptide, was observed to the same extent as in control ganglia. Furthermore, almost all of the somatostatin-immunoreactive varicose nerve fibres had disappeared, whereas a fairly dense network of calcitonin gene-related peptide-immunoreactive nerve fibres could be observed. This change was paralleled by an increased content of nerve fibres that were immunoreactive to antibodies against the growth-associated protein GAP-43 (also known as B-50). The present findings suggest that experimental perturbations where postganglionic neurons are separated from their target areas by axotomy, not only induce differential changes in neurotransmitter expression in the principal ganglion cells, but also in preganglionic sympathetic neurons projecting to the ganglia. One possible explanation for the occurrence of an axotomy-induced network of calcitonin gene-related peptide-immunoreactive nerve fibres, is that extrinsic sensory nerve fibres grow into the ganglia after the sciatic nerve lesion. Thus, these findings seem to suggest one additional possibility with regard to the question of a possible interaction between sympathetic and sensory neurons after peripheral nerve injury.

Distribution and origin of peptide-containing nerve fibres in the rat and human mammary gland.

The structures in the mammary gland involved in milk ejection have been investigated with regard to their relation to different types of peptidergic nerve fibres and their origin. Lactating rats were studied with immunohistochemistry focusing on the nipple, the parenchyma, the mammary blood vessels and the mammary nerve. The human mammary gland was also analysed. In the mammary gland from rat and human, nerve endings in the subepidermis, around smooth muscle cells in the nipple, in the connective tissue surrounding lactiferous ducts and alveoli in the nipple and in the parenchyma of the mammary gland showed immunoreactivity for calcitonin gene-related peptide, substance P, vasoactive intestinal polypeptide, peptide histidine isoleucine, neuropeptide Y, galanin and tyrosine hydroxylase, whereas dynorphin-positive nerve fibres could not be detected. The mammary nerve contained calcitonin gene-related peptide, vasoactive intestinal polypeptide, neuropeptide Y and tyrosine hydroxylase immunoreactivities; the adventitia of the mammary artery contained nerve fibres immunoreactive for neuropeptide Y and tyrosine hydroxylase, while vasoactive intestinal polypeptide-, peptide histidine isoleucine-, calcitonin gene-related peptide- and substance P-positive fibres were found in the tissue surrounding the artery. The wall of the mammary vein had nerve terminals immunoreactive for neuropeptide Y, tyrosine hydroxylase, calcitonin gene-related peptide and substance P. With the help of retrograde tracing using wheat germ agglutinin in combination with immunohistochemistry, projections of calcitonin gene-related peptide-immunoreactive cells in the dorsal root ganglia to the nipple were established. Neurons in the sympathetic stellate ganglion containing neuropeptide Y and tyrosine hydroxylase also projected to the mammary gland. Moreover retrogradely-labelled cells were found in the nodose ganglion, and they were vasoactive intestinal polypeptide-immunoreactive. These results demonstrate a rich distribution of different types of nerve fibres in structures of the mammary gland related to milk ejection. These nerve fibres and their peptides may be involved in the local control of milk ejection.

Structural and functional aspects of acetylcholine peptide coexistence in the autonomic nervous system.

The present article is an attempt to briefly review acetylcholine and peptide coexistence in the ANS. For more detailed information the reader is referred to the book by Furness and Costa (1987) and books edited by Elfvin (1983) and Björklund et al. (1988). Acetylcholine is the "classical" transmitter substance between preganglionic and post-ganglionic neurons in both the sympathetic and parasympathetic nervous system but also between postganglionic parasympathetic neurons and effector cells. ENK and NT were early on shown to be present in preganglionic sympathetic neurons whereas SP and SOM have more recently been associated with these cells. Physiological experiments have shown that ENK may presynaptically inhibit cholinergic transmission in sympathetic ganglia. The cholinergic postganglionic parasympathetic neurons contain VIP/PHI. These peptides may be responsible for the atropine-resistant vasodilation seen after stimulation of parasympathetic nerves. In salivary glands VIP has been shown to potentiate the salivatory volume response to ACh. A number of postganglionic sympathetic neurons innervating exocrine sweat glands in the skin are also cholinergic. In addition to VIP/PHI, these neurons contain CGRP and probably also SP. The functional significance of acetylcholine coexisting with four vasodilatory peptides in this cell population is at present unclear. In the enteric ganglia the coexistence situation is very complex. Thus, in the myenteric plexus cholinergic SP-containing excitatory motor neurons seem to be present. In the myenteric plexus other cholinergic neurons may contain at least six different neuronal peptides. These latter neurons seem to be part of the peripheral intestino-intestinal reflex arc which is involved in regulation of gastrointestinal motility and mucosal functions. In the submucous plexus three populations of cholinergic neurons are present, one of which has secretomotor properties and contains CGRP, CCK, GAL, NPY and SOM. In vivo and in vitro studies have shown that developing sympathetic neurons can "change" the "classical" transmitter they-use and alter their neuropeptide expression. If dissociated sympathetic neurons are grown in cultures without any non-neuronal elements they differentiate into a noradrenergic phenotype. However, if the cultures also contain non-neuronal cells, both noradrenergic and cholinergic properties will develop. These changes may also by induced by a conditioned medium, containing a diffusible factor secreted from the non-neuronal cells. In conclusion, the present article underlines the complexity of the chemical neuroanatomy of the ANS and emphasizes the abundance of the peptides in both noradrenergic and cholinergic neurons. Although these peptides can be shown to exert a number of interesting effects in various experimental paradigms, much work is needed to define their exact role in nervous system function.

Effects of preganglionic sympathectomy on peptides in the rat superior cervical ganglion.

A novel method to selectively lesion preganglionic sympathetic neurones has been combined with immunohistochemistry to study the expression of peptides in the rat superior cervical ganglion (SCG). Thus, systemic administration of monoclonal antibodies against acetylcholinesterase (AChE) caused a marked reduction in the number of enkephalin (ENK)-positive fibres and a total disappearance of fibres immunoreactive for calcitonin gene-related peptide (CGRP) and AChE in the SCG. A marked increase in the number of galanin/galanin message-associated peptide (GAL/GMAP)-immunoreactive cell bodies was also observed. The present results indicate that probably all CGRP and most ENK containing fibres in the rat SCG are of preganglionic origin and that peptides not normally expressed in SCG neurones, e.g. GAL and GMAP, can be upregulated after deafferentation.

WGA-HRP and choleragenoid-HRP as anterogradely transported tracers in vagal visceral afferents and binding of WGA and choleragenoid to nodose ganglion neurons in rodents.

The axonal and terminal labelling pattern in the brain stem resulting from the injection of horseradish peroxidase (HRP) conjugate of wheat germ agglutinin (WGA) or choleragenoid into the nodose ganglion of guinea pigs was examined. In addition, the binding profiles of WGA and choleragenoid in the nodose ganglion of guinea pig and rat were examined. The results show that WGA-HRP and choleragenoid-HRP (B-HRP) produce almost identical distribution of axonal and terminal labelling, the difference being some contralateral fibre labelling present only with B-HRP. However, WGA-HRP shows the strongest labelling at short survival times, whereas B-HRP requires longer postoperative survival times to reach maximum labelling intensity. All nodose ganglion neurons appear to bind WGA as well as choleragenoid although to a varying degree. The results of this and previous studies support the view that visceral sensory ganglion cells and the large light subpopulation of somatic dorsal root ganglion cells both bind choleragenoid, whereas the small dark somatic cells show affinity for WGA but rarely for choleragenoid.

An ultrastructural study of dynorphin-immunoreactive nerve fibers and terminals in the celiac-superior mesenteric ganglion of the guinea pig.

Dynorphin-immunoreactive nerve fibers and terminals were identified in the celiac-superior mesenteric ganglion of the guinea pig at the ultrastructural level with the peroxidase-antiperoxidase technique. The immunostained material was localized in the large dense core vesicles of the terminals but was also present diffusely in the axoplasm. The terminals formed numerous axodendritic and a few axosomatic contacts, interpreted as synapses, with the principal ganglion cells. These findings suggest that dynorphin plays a role as a neurotransmitter or neuromodulator in the ganglion and, taken together with earlier findings, indicate an involvement of dynorphin neurons in the intestino-intestinal inhibitory reflex.

Evidence of substance P immunoreactive neurons in dorsal root ganglia and vagal ganglia projecting to the guinea pig pylorus.

The origin of extrinsic substance P fibers in the guinea pig pyloric wall was investigated by combining retrograde axonal tracing and indirect immunofluorescence techniques. After injection of Fast Blue into the pyloric wall labeled cells were found in the T7-T9 dorsal root ganglia and the nodose and jugular ganglia. About 60% of the labeled cells in the dorsal root ganglia contained substance P-like immunoreactivity. After local application of colchicine, a few substance P positive cells were observed in the nodose and jugular ganglia, some of which also contained Fast Blue.

Substance P mRNA is present in a population of CGRP-immunoreactive cholinergic postganglionic sympathetic neurons of the cat: evidence from combined in situ hybridization and immunohistochemistry.

A synthetic oligonucleotide probe, complementary to a sequence of the rat beta-preprotachykinin mRNA coding for part of the mature substance P (SP), was used to localize, by in situ hybridization, SP mRNA to individual paravertebral sympathetic ganglion cells of the cat. Subsequent immunohistochemical analysis revealed that most of these neurons contained immunoreactivity to calcitonin gene-related peptide (CGRP), suggesting that they belong to the cholinergic cell population of the scattered type. These cells contain, in addition to SP and CGRP, vasoactive intestinal polypeptide and peptide histidine isoleucine.

Measurements of the DNA amount in mono- and binucleate cells in the celiac superior mesenteric ganglion of the guinea pig.

The relative proportion, ultrastructure and DNA-content of the binucleate cells in the celiac superior mesenteric ganglion of the guinea pig was studied using light and electron microscopy as well as computerized image analysis of Feulgen stained cells. The number of mono - versus binucleate cells was found to vary with stage of development with about 40% of the cells being binucleate in adult animals and 50% in late prenatal stage. No difference in ultrastructure was observed between the nuclei of the two cell types. The binucleate cells contain twice the amount of DNA found in the mononucleate cells.

Simultaneous immunohistochemical demonstration of intra-axonally transported markers and neuropeptides in the peripheral nervous system of the guinea pig.

Projections and peptide neurotransmitter/neuromodulator content of autonomic and visceral afferent neurons of the guinea pig were studied after application of the subunit B of cholera toxin (CTB) with or without horseradish peroxidase (HRP) as retrograde and anterograde tracers and subsequent immunohistochemical processing for double staining using antibodies raised to CTB, HRP and various neuropeptides. The results demonstrate that substance P (SP)- and calcitonin gene-related peptide (CGRP)-containing dorsal root ganglion cells project to the pylorus as well as to the celiac superior mesenteric and stellate ganglia as demonstrated with both retrograde and anterograde transport methodology. Binding studies revealed that a small number of the CTB-binding dorsal root ganglion cells contains immunoreactivity to SP and CGRP. The majority of the CTB-binding cells is SP- and CGRP-negative and terminate in the deeper parts of the dorsal horn. After injection of CTB conjugated to HRP (B-HRP) into the nodose ganglion, both motor and sensory elements were labeled in the medulla oblongata. Some of the CTB labeled vagal sensory nerve fibers in the nucleus tractus solitarii (NTS) were also found to contain immunoreactivity to SP or CGRP. The tracer was also transported through the peripheral branch of the nodose ganglion cells and labeled terminals in the esophagus.

NPY-, galanin-, VIP/PHI-, CGRP- and substance P-immunoreactive neuronal subpopulations in cat autonomic and sensory ganglia and their projections.

The neuronal subpopulations in the cat stellate, lower lumbar and sacral sympathetic ganglia were studied with regard to the cellular distribution of immunoreactivity to tyrosine hydroxylase (TH), acetylcholinesterase (AChE) and various neuronal peptides. Coexistence of neuropeptide Y (NPY)- and galanin (GAL)-like immunoreactivity (LI) was found in a high proportion of the neuronal cell bodies; these cells also contained immunoreactivity to TH, confirming their presumably noradrenergic nature. Some TH- and GAL-immunoreactive principal ganglion cells lacked NPY-LI. Two populations (scattered and clustered) of vasoactive intestinal polypeptide (VIP)- and peptide histidine isoleucine (PHI)-positive cell bodies were found in the sympathetic ganglia studied. The scattered VIP/PHI neurons also contained AChE-LI, calcitonin gene-related peptide (CGRP)-and, following culture, substance P (SP)-LI. The clustered type only contained AChE-LI. In the submandibular and sphenopalatine ganglia, neurons were AChE- and VIP/PHI-immunoreactive but lacked CGRP- and SP-LI. Many GAL- and occasional TH-positive neurons were found in these ganglia. In the spinal ganglia, single NPY-immunoreactive sensory neuronal cells were observed, in addition to CGRP- and SP-positive neurons. The present results show that there are at least two populations of sympathetic cholinergic neurons in the cat. Retrograde tracing experiments indicate that the scattered type of cholinergic neurons contains four vasodilator peptides (VIP, PHI, CGRP, SP) and provides an important input to sweat glands, whereas the clustered type (containing VIP and PHI) mainly innervates blood vessels in muscles.

Immunohistochemical demonstration of choline acetyltransferase-immunoreactive preganglionic nerve fibers in guinea pig autonomic ganglia.

The distribution of choline acetyltransferase (ChoAcTase)-like immunoreactivity in the superior cervical ganglion and the stellate ganglion was analyzed with immunohistochemistry. A dense network of ChoAcTase-immunoreactive nerve fibers was observed in both ganglia studied. The ChoAcTase-positive fibers were found in all parts of the ganglia but had a differential distribution, giving rise to a patchy staining pattern. After preganglionic denervation of the superior cervical ganglia, all ChoAcTase-positive fibers disappeared. For comparison, the distributions of enkephalin- and neuropeptide Y-like immunoreactivity were analyzed. In the stellate ganglion, the enkephalin-positive fibers had a marked regional distribution. Areas with the highest enkephalin-fiber density seemed to contain low numbers of ChoAcTase-positive fibers and vice versa. The findings give evidence for occurrence of acetylcholine synthesis in preganglionic fibers in paravertebral sympathetic ganglia.

p53 and vascular-endothelial-growth-factor (VEGF) expression predicts outcome in 833 patients with primary breast carcinoma.

The angiogenic factor vascular endothelial growth factor (VEGF) predicts outcome in primary breast carcinoma. Alteration of the p53 gene causes down-regulation of the expression of thrombospondin-1, a natural inhibitor of angiogenesis. This study was conducted to investigate the association between mutant p53 protein and VEGF expression, and the prognostic value of these factors. VEGF165 and p53 protein were measured in tumour cytosols by enzyme immunoassays. Recurrence-free survival (RFS) and overall survival (OS) were estimated in 833 consecutive patients, 485 node-negative (NNBC) and 348 node-positive (NPBC) with primary invasive breast cancer. A significant association was found between mutant p53 protein and VEGF expression. Univariate analysis showed both p53 and VEGF to be significant predictors of survival. Similar correlation was seen when p53 was combined with VEGF. Univariate analysis of NNBC showed significant prognostic value of p53 for OS, also when combined with VEGF expression; for NPBC, significant reductions in RFS and OS were seen for p53-positive patients, and these findings were enhanced when combined with VEGF, also in the sub-group receiving adjuvant endocrine treatment. Multivariate analysis showed both p53 and VEGF as independent predictors of OS in all groups. When the 2 factors were combined, an increased relative risk of 2.7 was seen for OS in the group with both p53 positivity and high VEGF content, as compared with 1.7 in the group with one risk factor. The results suggest an association between loss of wt-p53 and increased VEGF expression, indicating that angiogenic activity may depend, at least partly, on altered p53-protein function. Combination of these 2 biological markers appears to give additional predictive information of survival. A high-risk group of patients was associated with p53 positivity and higher VEGF content.

Topography of NPY-, somatostatin-, and VIP-immunoreactive, neuronal subpopulations in the guinea pig celiac-superior mesenteric ganglion and their projection to the pylorus.

The topography of the peptidergic neuronal subpopulations in the guinea pig celiac-superior mesenteric ganglion was studied analyzing the distribution of immunoreactivity to neuropeptide Y (NPY), somatostatin (SOM), and vasoactive intestinal polypeptide (VIP)/polypeptide HI (PHI). For comparison, the ganglion was also studied using antisera against the 2 catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). Approximately 65% of the neuronal cell bodies contained NPY-like immunoreactivity (NPY-LI), whereas 25% of the principal ganglion cells contained SOM-like immunoreactivity (SOM-LI). Though occasional cells were found to contain both NPY-LI and SOM-LI, these peptides had a complementary distribution in the ganglion, with NPY cells in the celiac poles and SOM cells in the superior mesenteric pole. The vast majority of both the NPY- and SOM-positive cells also contained TH-like immunoreactivity (TH-LI), confirming their catecholaminergic, presumably noradrenergic, nature. Some noradrenergic neurons seemed to lack NPY- and SOM-LI. Small numbers of VIP/PHI-containing cell bodies were found in areas where the NPY-immunoreactive neurons predominated. Many of the VIP/PHI-positive cells contained NPY-LI and occasionally also TH-LI. The immunohistochemical markers were also observed in fibers. Thus, a comparatively weak NPY-LI was seen in smooth fibers, probably representing axons and axon bundles. SOM-LI was seen in a similar type of fiber but also in more strongly fluorescent fibers with a varicose appearance. The latter fibers were observed only in the SOM-dominated part of the ganglion, often surrounding the ganglion cells. Varicose fibers with a similar distribution containing DBH-like immunoreactivity (DBH-LI) were also seen. In addition, DBH- and TH-LI were seen in smooth axonlike processes. VIP-positive fibers exhibited a very dense fiber network, almost exclusively related to the SOM cell-dominated part of the ganglion. The projection of the postganglionic sympathetic neurons was studied with special reference to the pylorus using a combination of retrograde axonal tracing and indirect immunofluorescence techniques. Seventy-two hours after injection of the fluorescent tracer Fast Blue into the pyloric sphincter, labeled neurons were found in the ganglion. By comparing the Fast Blue-labeled cells with the immunoreactive cell bodies, neurons containing both dye and NPY- or SOM-LI were observed. In elution-restaining experiments, it was established that the majority of these cells were also immunoreactive to TH, indicating that they produce noradrenaline.(ABSTRACT TRUNCATED AT 400 WORDS)