Method of intravital injection of the internal blood vessels of organs for experimental-morphological research]

Ten minutes before the injection the rat is given heparin (500 units per 1 kg weight) intradermally. To the narcotized animal, the needle with the 1 ml syringe is inserted and 3--5 ml of blood are aspirated (about 2% of the body mass). Then with the same needle another syringe of 10 ml volume containing filtrated and heated up to 40 degrees C undiluted Indian ink is injected. The amount of the Indian ink injected is 8--10 ml per 100 g of the body mass. We can consider the injection oa success if the mucose of the tongue, the skin of the concha auriculae, the sclera of the eye are promptly stained during the injection and the tail vessels are well filled.     

The development of an identified subpopulation of avian sensory neurons is regulated by interaction with the periphery

The monoclonal antibody, SN1, binds to the cell surface of a subpopulation of avian sensory neurons. Dorsal root ganglia (DRG) that innervate different peripheral fields contain significantly different proportions of SN1(+) neurons. Moreover, the developmental time of appearance of these neurons suggests that they normally express SN1 immuno-reactivity only after they have made contact with their normal peripheral targets (Marusich et al., 1986). In the present paper, we test the hypothesis that the proportion of SN1(+) neurons within DRG is regulated by interactions between the developing neurons and their peripheral targets. Thus, immature DRG explanted into a defined medium show an age-dependent increase in the proportion of cells able to become SN1(+), but fail to show the large increase in number of immunoreactive neurons that occurs in vivo. Moreover, unilateral wing bud extirpations performed at E3 (prior to wing innervation) resulted in a dramatic selective decrease in the number of SN1(+) neurons within DRG that normally innervate the wing. These results support the hypothesis that peripheral targets regulate the appearance of SN1(+) neurons.     

Projection of the neurons of the substantia nigra and ventral field of the midbrain tegmen in the cat to the putamen

By means of retrograde axonal transport of the horseradish peroxidase and fluorochromes in the cat, it has been stated that neurons of all the parts of the substantia nigra (SN) make projections to the putamen. These projections are organized in such a way that the rostral part of the putamen gets the projected fibers from less number of the SN parts than the caudal part. To the caudal part of this formation all parts of the SN are projected, and in the equal degree to its dorsal and ventral segments. Projections to the rostral part are sent only from two parts of the SN--compact and dorsal. To the dorsal segment of this part only axons from a small amount of the nigral neurons are sent. A small amount of neurons of the tegmental ventral field give projections to the ventral segments along the whole rostrocaudal extent of the putamen. Convergence of the SN neuronal axons in the formations of the striated body has been determined, as well as overlapping of the terminal fields in the putamen from the projective neurons of the nigral various parts. Besides in different parts of the SN discrepancy has been revealed in the neuronal populations, labelled with different stainings, that contain cells, marked with two markers, injected into the nucleus caudatus and into the putamen.     

Increased expression of inducible nitric oxide synthase and peroxynitrite in Helicobacter pylori gastric ulcer.

The role of nitric oxide in ulcer formation remains unknown. Accordingly, we assessed local expression of inducible nitric oxide synthase (NOS) and nitration of tyrosine as an indicator of peroxynitrite formation in patients with Helicobacter pylori (HP)-associated gastric ulcers compared with HP-negative ulcers. Biopsy specimens were taken from the ulcer margin and from an area remote from the ulcer portion. Inducible NOS, nitrotyrosine, and macrophage immunoreactivity were assessed immunohistochemically using a labeled streptavidin-biotin method. In HP-positive gastric ulcers, inducible NOS and nitrotyrosine immunoreactivity was frequently observed at active ulcer margins, sometimes in surface epithelial cells as well as in the lamina propria. Occasionally, inducible NOS and nitrotyrosine reactivity were found in areas remote from the lesion in cases of HP-positive ulcer and HP-related gastritis. Macrophages accumulated significantly in the margin of HP-positive ulcers. In HP-negative gastric ulcers, inducible NOS and nitrotyrosine immunoreactivity also were frequent at the ulcer margin, but no significant immunoreactivity was observed at a distance. HP eradication caused significant attenuation in inducible NOS and macrophage immunoreactivity. In conclusion, nitric oxide and peroxynitrite formation is increased in HP-infected gastric mucosa, suggesting that HP promotes nitric oxide stress.     

Structure and localization of sympathetic neurons in the cat spinal cord

By the method of retrograde axonal transport of horseradish peroxidase (HP) structure and localization of sympathetic neurons sending axons to the cranial cervical ganglion (CCG) have been revealed ipsilaterally in the ventral horns and in 4 nuclei of the spinal cord: nucl ILp, nucl. ILf. nucl. IC, nucl. ICpe. Orientation of the neurons, their number, structure of the nuclei formed by them, degree of the CCG efferentation by the preganglionic fibres, which run from various nuclei, are different. In nucl. ILf two types of neurons have been revealed-triangle and spindle-shaped, they always orienting by their long axis in mediolateral direction. The greatest amount of HP-positive neurons are found in nucl. ILp. They form a well distinquished compact nucleus in the lateral horns. HP-labelled neurons in nucl. ILp are found at the level of segments T1-T8 with their maximal amount at the level of segments T1-T3. HP-positive neurons are detected in nucl. ILf beginning from the segment C8 up to the middle of T4, in nucl. IC-from the segment C8 up to T6, in nucl. ICpe-from the segment C8 up to T5, in the ventral horns-from the segment T1 up to T5. In rostocaudal direction from the segment C8 up to T8 the number of HP-positive neurons is decreasing, but the part of nucl. ILp neurons in the CCG efferentation, comparing to the neurons in other sympathetic structures of the spinal cord, is increasing.     

Development of synaptic connections between different segmental motoneurones striated muscles in an axolotl limb.

The pattern of innervation of the hindlimb flexor muscle surface of the mature axolotl by segmental nerves 16 and 17 (i.e., SN16 and 17) is approximately constant, if there is no innervation by nerve 18. If the proximal flexor muscle surface is divided into six equal sectors, it is found that sector 1 is only innervated by SN17, sector 2 by both SN16 and 17, sectors 3 and 4 by SN16, and sectors 5 and 6 by both SN16 and 17. In tadpole axolotls, when the flexor hindlimb muscle is about 1.5 mm long, muscle cells in all sectors can be found which were innervated by both SN16 and 17. During subsequent development the incorrect synaptic contacts are lost, and by the time the flexor muscle has reached a length of 5.5 mm the mature pattern of innervation is attained. At later stages of development a further loss of synapses is observed which appears to be unassociated with any change in the pattern of innervation of the flexor hindlimb muscle. These observations suggest the hypothesis that very early during development segmental motoneurones make incorrect connections on muscle cells, with the terminals of foreign motoneurones regressing in favour of the terminals of correct motoneurones.     

Localization of heart-innervating sympathetic neurons

Localization, amount, form of the bodies and maximal diameter of horseradish peroxidase (HP)-labelled neurons in the right stellate ganglion (SG) in the cat spinal cord have been investigated. HP application has been performed on the central parts of the SG connective branch with vagus nerve, or with the caudal cardiac nerve. In the neurons HP has been revealed after Straus or Mesulam method. In the SG, regardless the HP application place, the labelled neurons arrange in the zone, adjoining the place, where the caudal cardiac nerve and the connective branch get to the vagus nerve. In the spinal cord, when HP is applied on the connective branch, the labelled neurons are revealed in the lateral horns of the TI-TVI segments. The amount of the labelled neurons decreases in the rostro-caudal direction. Their greatest amount is revealed in the TI-TIII segments. When HP is applied on the central part of the caudal cardiac nerve, a small amount of the labelled neurons has been found in TI-TIII segments of the spinal cord only in one experiment. Thus, in the connective branch of the SG with the vagus nerve much more amount of the preganglionar fibers run than in the caudal cardiac nerve.     

Distribution of microglia in the postnatal murine nigrostriatal system

Parkinson’s disease (PD) is characterized by the degeneration of dopaminergic neurons in the substantia nigra (SN) and the subsequent loss of striatal target innervation. Neuroinflammatory responses have been described for virtually all PD cases analysed. Microglia are the resident immune cells of the central nervous system and, thus, are the mediators of neuroinflammation. Approximately 12% of all central nervous system cells are microglia but the distribution and density of microglia differ within distinct brain regions. Interestingly, the SN has been shown to contain more microglia than adjacent structures. We have analysed changes in microglia numbers and in microglial morphology in the postnatal murine nigrostriatal system at various stages ranging from postnatal day 0 (P0) up to 24 months of age. We clearly show that the microglia numbers in the SN and in the striatum dramatically increase from P0 to P15 and significantly decrease in both areas in 18-month-old and 24-month-old animals. Moreover, microglia in the nigrostriatal system of aged mice show signs of dystrophy and degeneration, such as cytoplasmic inclusions, deramification of their processes and membrane blebbing. Our results support the hypothesis of microglial dystrophy during aging in the murine nigrostriatal system, accompanied by subsequent impairment of normal microglial functions. Microglial dysfunction during aging might be a potential risk factor for the development and/or progression of PD.     

Distribution of spinal sensory neurons supplying the adrenal gland in the pig

The present study was aimed at disclosing which spinal ganglia contribute to the innervation of the adrenal gland in the pig with special regard to the morphology and intraganglionic distribution of the primary sensory neurons within these ganglia. To this end, the animals were injected with a retrograde fluorescent neuronal tracer Fast Blue into the left adrenal gland during laparotomy. After a survival period of three weeks, labelled spinal sensory neurons were found in the ipsilateral dorsal root ganglia (approximately 99% of all retrogradely marked neurons). However, single adrenal gland-projecting perikarya were observed also in the contralateral dorsal root ganglia from Th3 to L3. The majority of the retrogradely labelled afferent neurons (above 65% of all Fast Blue-positive (FB+) perikarya) were located in two groups of spinal ganglia (at neuromeres Th6-7 and Th12-14, approximately 18% and 47% of neurons, respectively), forming two distinct multiganglionic centres of origin for this neural pathway. The morphometric evaluation of FB+ neurons revealed that the vast majority of them (approximately 81%) belonged to the class of small-sized perikarya (10-30 microm in diameter), while the medium-sized (diameter 30-80 microm) and large neurons comprised only up to 13% and 6.5% of adrenal gland-projecting neurons, respectively. Furthermore, the analysis of the intraganglionic distribution pattern of the retrogradely labelled cells revealed that the highest number of them was located in the medio-caudal domain of the dorsal root ganglia, irrespective of the neuromere studied. Thus, the present study has revealed sources and morphological characteristic of spinal afferent neurons supplying the porcine adrenal gland, simultaneously pointing out to the characteristic features of their inter- and intraganglionic distribution pattern.     

小儿消化性疾病的胃电图变化及与临床特点和胃镜特征的关联性

目的:分析小儿消化性疾病的胃电图变化及与临床病理特征和胃镜特征的关联性。方法:选取2018年1月至2019年5月我院儿科收治的经胃镜和病理学两种方式诊断为消化性疾病的患儿54例为观察组,另选取无胃肠道疾病的健康儿童40例为对照组。比较两组胃电图参数(频率均值和波幅均值),54例胃电图诊断后纤维胃镜检查结果,分析消化性疾病患儿HP感染与临床病理特征、溃疡面积的关系。结果:各组胃病患者胃电慢波频率均值各不相同(P0.05),三组患者胃电慢波波幅均值相比差异具有统计学意义(P0.05);且浅表性胃炎组、胆汁反流性胃炎组患者胃电慢波频率均值、胃电慢波波幅均显著低于胃溃疡组(P0.05);浅表性胃炎组患者胃电慢波频率均值显著低于胆汁反流性胃炎组(P0.05)。胆汁反流性胃炎组患者胃电慢波波幅显著低于浅表性胃炎组(P0.05)。胃镜检查结果显示,其中浅表性胃炎的诊断符合率较高,达90.00%,胃溃疡符合率为60.71%,胆汁反流性胃炎符合率为83.33%。HP检测结果显示,HP阳性患儿占总例数的77.78%(42/54),HP阴性患儿占总例数的22.22%(12/54);HP阳性组患儿淋巴滤泡形成、胃黏膜萎缩、胃黏膜炎性活动的发生率明显高于HP阴性组,差异具有统计学意义(P0.01);HP阳性组溃疡范围2 cm的患儿比例明显高于HP阴性患儿,差异具有统计学意义(P0.01)。结论:小儿消化性疾病胃电图存在餐后NSWP的下降及节律过缓的上升,胃电图检查和胃镜检查在诊断上有较高的符合率,HP感染科引起胃黏膜组织学改变,可作为小儿消化性疾病的靶向治疗。     

The neural control of spermathecal contractions in the locust,Locusta migratoria

The innervation of the spermatheca and demonstration of neural control of spermathecal contractions in Locusta migratoria was illustrated using anterograde and retrograde fills, combined with electrophysiological stimulation and recording. The anterior portion of the spermatheca receives innervation via the receptaculum seminis nerve (N2B2) from two large ventral neurons and one dorsal neuron. All were bilaterally paired and situated in the VIIIth abdominal ganglion. Three ventral bilaterally paired neurons situated in the VIIIth abdominal ganglion also provide innervation to the posterior portion of the spermatheca via the ductus seminalis aperture nerve (N2B3). Six DUM neurons, located in the VIIIth abdominal ganglion, in addition to two centroposteriorly situated DUM neurons in the VIIth abdominal ganglion, are also associated with these two nerves. N2B4 also provides innervation to the posterior portion of the spermatheca. N2B6b is associated with sensory cells identified in the anterior lateral regions of the genital chamber. The spermatheca contracts spontaneously, with peristaltic contractions beginning at the spermathecal sac and continuing along the length of the spermathecal duct. However electrical stimulation of the ventral ovipositor nerve (VON or N2B), receptaculum seminis nerve (N2B2) and the ductus seminalis aperture nerve (N2B3) indicates that contractions are also under neural control. In particular contractions of the spermathecal sac, coil duct and anterior straight duct are initiated via motor projections from the receptaculum seminis nerve (N2B2) and posterior straight duct contractions are controlled by motor input from the ductus seminalis aperture nerve (N2B3). The results suggest that spermathecal contractions of the anterior and posterior portions of the spermatheca are under separate neural control.     

Ionic currents and secretion in the exocrine glands

Exocrine glands extrude both proteins and salt. Fluid secretion is related to a modification of the membrane permeability of secreting cells. This permeability change may be measured as an increase of labelled ion fluxes or as a rise of membrane conductance. It involves Na+, K+, Cl- and Ca2+ ions. Intracellular Ca2+ acts as "second messenger" in the development of the electrical response. Recent recordings using the "patch-clamp" technique have revealed three types of ion channel activated by secretory agents. These channels are sensitive to internal Ca2+ ions. They are respectively selective to K+, Cl- and positively charged monovalent ions. Two models suggesting possible roles for these channels in the secretion process are presented. However, evaluation of such models is presently restricted by numerous uncertainties on the function of secreting cells in vivo. Information is notably lacking concerning the exact composition of the secreted fluid, and the exchanges between exocrine glands and blood circulation.     

Peripheral nerve lesion-induced uptake and transport of choleragenoid by capsaicin-sensitive c-fibre spinal ganglion neurons

In the present experiments the effect of systemic capsaicin treatment on the retrograde labelling of sensory ganglion cells was studied following the injection of choleratoxin B subunit-horseradish peroxidase conjugate (CTX-HRP) into intact and chronically transected peripheral nerves. In the control rats CTX-HRP injected into intact sciatic nerves labelled medium and large neurons with a mean cross-sectional area of 1,041 +/- 39 gm2. However, after injection of the conjugate into chronically transected sciatic nerves of the control rats, many small cells were also labelled, shifting the mean cross-sectional area of the labelled cells to 632 +/- 118 microm2. Capsaicin pretreatment per se induced a moderate but significant decrease in the mean cross-sectional area of the labelled neurons (879 +/- 79 microm2). More importantly, systemic pretreatment with capsaicin prevented the peripheral nerve lesion-induced labelling of small cells. Thus, the mean cross-sectional areas of labelled neurons relating to the intact and transected sciatic nerves, respectively, did not differ significantly. These findings provide direct evidence for a phenotypic switch of capsaicin-sensitive nociceptive neurons after peripheral nerve injury, and suggest that lesion-induced morphological changes in the spinal cord may be related to specific alterations in the chemistry of C-fibre afferent neurons rather than to a sprouting response of A-fibre afferents.     

Retinoic acid-mediated enhancement of the cholinergic/neuronal nitric oxide synthase phenotype of the medial septal SN56 clone: establishment of a nitric oxide-sensitive proapoptotic state

It is unclear what mechanisms lead to the degeneration of basal forebrain cholinergic neurons in Alzheimer's or other human brain diseases. Some brain cholinergic neurons express neuronal nitric oxide (NO) synthase (nNOS), which produces a free radical that has been implicated in some forms of neurodegeneration. We investigated nNOS expression and NO toxicity in SN56 cells, a clonal cholinergic model derived from the medial septum of the mouse basal forebrain. We show here that, in addition to expressing choline acetyltransferase (ChAT), SN56 cells express nNOS. Treatment of SN56 cells with retinoic acid (RA; 1 microM) for 48 h increased ChAT mRNA (+126%), protein (+88%), and activity (+215%) and increased nNOS mRNA (+98%), protein (+400%), and activity (+15%). After RA treatment, SN56 cells became vulnerable to NO excess generated with S-nitro-N-acetyl-DL-penicillamine (SNAP) and exhibited increased nuclear DNA fragmentation that was blocked with a caspase-3 inhibitor. Treatment with dexamethasone, which largely blocked the RA-mediated increase in nNOS expression, or inhibition of nNOS activity with methylthiocitrulline strongly potentiated the apoptotic response to SNAP in RA-treated SN56 cells. Caspase-3 activity was reduced when SNAP was incubated with cells or cell lysates, suggesting that NO can directly inhibit the protease. Thus, whereas RA treatment converts SN56 cells to a proapoptotic state sensitive to NO excess, endogenously produced NO appears to be anti-apoptotic, possibly by tonically inhibiting caspase-3.     

Cutaneous overexpression of NT-3 increases sensory and sympathetic neuron number and enhances touch dome and hair follicle innervation

Target-derived influences of nerve growth factor on neuronal survival and differentiation are well documented, though effects of other neurotrophins are less clear. To examine the influence of NT-3 neurotrophin overexpression in a target tissue of sensory and sympathetic neurons, transgenic mice were isolated that overexpress NT- 3 in the epidermis. Overexpression of NT-3 led to a 42% increase in the number of dorsal root ganglia sensory neurons, a 70% increase in the number of trigeminal sensory neurons, and a 32% increase in sympathetic neurons. Elevated NT-3 also caused enlargement of touch dome mechanoreceptor units, sensory end organs innervated by slowly adapting type 1 (SA1) neurons. The enlarged touch dome units of the transgenics had an increased number of associated Merkel cells, cells at which SA1s terminate. An additional alteration of skin innervation in NT-3 transgenics was an increased density of myelinated circular endings associated with the piloneural complex. The enhancement of innervation to the skin was accompanied by a doubling in the number of sensory neurons expressing trkC. In addition, measures of nerve fibers in cross- sectional profiles of cutaneous saphenous nerves of transgenics showed a 60% increase in myelinated fibers. These results indicate that in vivo overexpression of NT-3 by the epidermis enhances the number of sensory and sympathetic neurons and the development of selected sensory endings of the skin.     

Extrinsic and intrinsic sources of calcitonin gene-related peptide immunoreactivity in the lamb ileum: a morphometric and neurochemical investigation

To investigate extrinsic origins of calcitonin gene-related peptide immunoreactive (CGRP-IR) nerve fibres in the sheep ileum, the retrograde fluorescent tracer Fast Blue (FB) was injected into the ileum wall. Sections of thoraco-lumbar dorsal root ganglia (DRG) and distal (nodose) vagal ganglia showing FB-labelled neurons were processed for CGRP immunohistochemistry. The distribution of CGRP-IR in fibres and nerve cell bodies in the ileum was also studied. CGRP-IR enteric neurons were morphometrically analysed in myenteric (MP) and submucosal plexuses (SMP) of lambs (2–4 months). Sensory neurons retrogradely labelled with FB were scattered in T5-L4 DRG but most were located at the upper lumbar levels (L1-L3); only a minor component of the extrinsic afferent innervation of the ileum was derived from nodose ganglia. In the DRG, 57% of retrogradely labelled neurons were also CGRP-IR. In cryostat sections, a dense network of CGRP-IR fibres was observed in the lamina propria beneath the epithelium, around the lacteals and lymphatic follicles (Peyer's platches), and along and around enteric blood vessels. Rare CGRP-IR fibres were also present in both muscle layers. Dense pericellular baskets of CGRP-IR fibres were observed around CGRP-negative somata. The only CGRP-IR nerve cells were well-defined Dogiel type II neurons localised in the MP and in the external and internal components of the SMP. CGRP-IR neurons in the myenteric ganglia were significantly larger than those in the submucosal ganglia (mean profile areas: about 1,400 μm² for myenteric neurons, 750 μm² for submucosal neurons). About 6% of myenteric neurons and 25% of submucosal neurons were CGRP-IR Dogiel type II neurons. The percentages of CGRP-IR neurons that were also tachykinin-IR were about 9% (MP) and 42% (SMP), whereas no CGRP-IR neurons exhibited immunoreactivity for vasoactive intestinal peptide, nitric oxide synthase or tyrosine hydroxylase in either plexus. Thus, CGRP immunoreactivity occurs in the enteric nervous system of the sheep ileum (as in human small intestine and MP of pig ileum) in only one morphologically defined type of neuron, Dogiel type II cells. These are probably intrinsic primary afferent neurons. This work was supported by grants from the Ricerca Fondamentale Orientata (RFO) and Fondazione Del Monte di Bo e Ra.     

大鼠三叉神经节神经元膜P2X嘌呤受体的特征

采用全细胞膜片钳技术研究了大鼠三叉神经节（trigeminal ganglion,TG）神经元膜P2X嘌呤受体的特征。结果发现：大部分受检细胞（78．9％,142／180）对ATP敏感,ATP．激活电流有明显的浓度依赖性。少数细胞无反应（21．1％,38／180）。在对ATP敏感的142个细胞中,绝大部分引起一内向电流（95．1％,135／142）,少数为外向电流（2．1％,3／142）,另有部分细胞出现双相电流（2．8％,4／142）。引起的内向电流在小直径细胞（〈30μm）上多表现为快去敏感电流,对vanilloid高度敏感;在中等大小的细胞（30～40μm）上多表现为慢去敏感电流,对vanilloid不敏感：绝大多数大细胞（〉40μm）对ATP和vanilloid均不敏感。此外,电流的波形与细胞直径密切相关。无论小细胞还是中等细胞其I-V曲线均表现出明显的内向整流趋势。我们还研究了ATP-激活电流的动力学特征,并观察了P2嘌呤受体激动剂、拮抗剂的效应。结果提示：不同类型的ATP受体．离子通道在不同类型的TG神经元上的表达具有不同的特点。     

Peptidergic motoneurons in the buccal ganglia of Aplysia californica Immunocytochemical,morphological, and physiological characterizations

Summary We used physiological recordings, intracellular dye injections and immunocytochemistry to further identify and characterize neurons in the buccal ganglia of Aplysia calif ornica expressing Small Cardioactive Peptide-like immunoreactivity (SCP-LI). Neurons were identified based upon soma size and position, input from premotor cells B4 and B5, axonal projections, muscle innervation patterns, and neuromuscular synaptic properties. SCP-LI was observed in several large ventral neurons including B6, B7, B9, B10, and B11, groups of s1 and s2 cluster cells, at least one cell located at a branch point of buccal nerve n2, and the previously characterized neurons B1, B2 and B15.B6, B7, B9, B10 and B11 are motoneurons to intrinsic muscles of the buccal mass, each displaying a unique innervation pattern and neuromuscular plasticity. Combined, these motoneurons innervate all major intrinsic buccal muscles (I1/I3, I2, I4, I5, I6). Correspondingly, SCP-LI processes were observed on all of these muscles. Innervation of multiple nonhomologous buccal muscles by individual motoneurons having extremely plastic neuromuscular synapses, represents a unique form of neuromuscular organization which is prevalent in this system. Our results show numerous SCPergic buccal motoneurons with widespread ganglionic processes and buccal muscle innervation, and support extensive use of SCPs in the control of feeding musculature.Abbreviations SCP-LI small cardioactive peptide-like immunoreactivity - PSC postsynaptic current - EPSP excitatory postsynaptic potential - IPSP inhibitory postsynaptic potential - FI facilitation index - TMR time to maximal response     

Distribution of enteric nerve cells projecting to the superior and inferior mesenteric ganglia of the guinea-pig

Retrograde tracing, using Fast Blue dye, was employed to determine the distribution of enteric nerve cells that project to the superior mesenteric and inferior mesenteric ganglia of the guinea-pig. Retrogradely labelled neurons were found in the myenteric but not submucous ganglia. When the superior mesenteric ganglion was injected, labelled neurons were found in low frequencies (less than 5 nerve cell bodies/cm²) in the duodenum, jejunum, ileum, caecum and proximal colon. The distal colon was analysed in five segments of equal length (1–5; oral to anal). Segment 1 had about 4 labelled nerve cells/cm², whereas segments 2 to 5 displayed an average of about 25 nerve cells/cm². The rectum contained about 36 labelled neurons/cm². After injection of the inferior mesenteric ganglia with Fast Blue, no labelled neurons were found in the duodenum, jejunum, ileum or caecum. No labelled cells were observed in the gallbladder. A small number of labelled cells occurred in the proximal colon and in segment 1 of the distal colon. The frequency of labelled cells increased markedly in the more anal regions of the distal colon, and reached a peak in the rectum (138 cells/cm²). Both nerve lesions and immersion of the cut nerve in Fast Blue solution showed that the superior mesenteric nerve carries the axons of neurons located in the middle distal colon to the superior mesenteric ganglion. Almost half of the neurons in the rectum that project to the inferior mesenteric ganglia do so via the hypogastric nerves. Of neurons that projected to the inferior or superior mesenteric ganglia from the colon or rectum, similar proportions (about 75–80%) showed immunoreactivity for calbindin or VIP. For each of the prevertebral ganglia (coeliac, superior mesenteric and inferior mesenteric) the great majority of peripheral inputs arise from the large intestine.