Maternal avoidance, anxiety cognitions and interactive behaviour predicts infant development at 12 months in the context of anxiety disorders in the postpartum period

BACKGROUND

Few studies have examined the relation between anxiety disorders in the postpartum period and cognitive as well as language development in infancy.

AIMS

This longitudinal study investigated whether anxiety disorder in the postpartum period is linked to infant development at twelve months. A closer look was also taken at a possible link between maternal interaction and infant development.

STUDY DESIGN

Subjects were videotaped during a Face-to-Face-Still-Face interaction with their infant (M = 4.0 months). Specific maternal anxiety symptoms were measured by self-report questionnaires (Anxiety Cognition Questionnaire (ACQ), Body Sensations Questionnaire (BSQ), Mobility Inventory (MI)) to check for a connection with infant development. The Bayley Scales of Infant and Toddler Development-III (Bayley-III) were used to assess infant language and cognitive development at one year of age.

SUBJECTS

n = 34 mothers with anxiety disorder (SCID-I; DSM-IV) and n = 47 healthy mothers with their infant.

OUTCOME MEASURES

Infant performance on Bayley-III language and cognitive scales.

RESULTS

Infants of mothers with anxiety disorder yielded significantly lower language scores than infants of controls. No significant group differences were found regarding infant cognitive development. Exploratory analyses revealed the vital role of "maternal avoidance accompanied" in infant language and cognitive development. Maternal neutral engagement, which lacks positive affect and vocalisations, turned out as the strongest negative predictor of cognitive development. Maternal anxiety cognitions and joint activity in mother-infant interaction were the strongest predictors of infant language performance.

CONCLUSIONS

Results underline the importance to also consider the interaction behaviour of women with anxiety disorders to prevent adverse infant development.

The influence of general anxiety and childbirth-specific anxiety on birth outcome

In the present study, we examined a German sample to determine whether anxiety symptoms during pregnancy had an impact on the duration and method of childbirth. Data of N = 88 women recruited at the Heidelberg University Hospital were used in the analyses. Prepartum anxiety symptoms were assessed with the State-Trait Anxiety Inventory (STAI, general anxiety) and the Pregnancy Related Anxiety Questionnaire (PRAQ-R, pregnancy-specific anxiety). Obstetric outcome was taken from birth records and operationalized by two parameters: the total duration of birth (dilation and fetal expulsion) and the incidence of pregnancy or birth-related interventions (ventouse, planned, and unplanned Cesarean section). The data show that childbirth-specific anxiety assessed by the PRAQ-R is an important predictor of total birth duration. In contrast, general anxiety measured by the STAI had no effect. The incidence of birth intervention was explained by parity. Anxiety, however, had no predictive value. In addition to medical factors, childbirth-specific anxiety during pregnancy plays an important role in the process of childbirth. The findings of the present study point to the need of implementing psychological interventions to reduce childbirth-specific anxiety and thereby positively influencing birth outcome.

Effect of APOE genotype on microvascular basement membrane in Alzheimer's disease

APOE4 homozygosity has been associated with an increased risk of sporadic Alzheimer's disease through a mechanism, which has yet to be defined. Recent evidence has suggested that microvascular basement membrane injury may be a critical factor in the pathogenesis of AD-related dementia. In previous studies, we have shown that the synaptic organizing protein agrin can be found in neurons, and is a major component of the brain microvascular basement membrane. Here, we compare the basement membrane surface area of cortical microvasculature in AD brains by staining with an anti-agrin antibody. Quantitative morphometric analysis was used to determine the mean basement area (micro(2)) of prefrontal cortical microvessels. An average of 10 capillaries was measured in each of 35 cases of AD genotyped for APOE status. APOE4,4 homozygotes had smaller capillary basement membrane areas (17.4 micro(2))+/-6.2) than APOE3,3 homozygotes (26.9 micro(2)+/-6.5), p<0.001. The capillary basement membrane areas (CBMA) of heterozygotes APOE3,4 did not differ significantly from APOE3,3 or APOE4,4. Braak stage did not contribute significantly to CBMA. However, a preliminary analysis suggests an interaction between APOE4,4 and Braak V-VI producing smaller CBMA, a finding which needs to be confirmed with a larger sample. These data support the hypothesis that APOE4,4 is associated with thinning of the microvascular basement membrane in Alzheimer's disease.

Molecular identification and sequence analysis of Hillarin, a novel protein localized at the axon hillock

The monoclonal antibody Lan3-15 identifies a novel protein, Hillarin, that is localized to the axon hillock of leech neurons. Using this antibody we have identified a full length cDNA coding for leech Hillarin and determined its sequence. The gene encodes a 1274 residue protein with a predicted molecular mass of 144013 Da. Data base searches revealed that leech Hillarin has potential orthologues in fly and nematode and that these proteins share two novel protein domains. The W180 domain is characterized by five conserved tryptophans whereas the H domains share 21 invariant residues. In contrast to the arrangement in fly and nematode the cassette containing the W180 and H domains is repeated twice in leech Hillarin. This suggests that the leech Hillarin sequence originated from a duplication event of an ancestral protein with single cassette structure.

Posttranslational processing and differential glycosylation of Tractin, an Ig-superfamily member involved in regulation of axonal outgrowth

Tractin is a novel member of the Ig-superfamily which has a highly unusual structure. It contains six Ig domains, four FNIII-like domains, an acidic domain, 12 repeats of a novel proline- and glycine-rich motif with sequence similarity to collagen, a transmembrane domain, and an intracellular tail with an ankyrin and a PDZ domain binding motif. By generating domain-specific antibodies, we show that Tractin is proteolytically processed at two cleavage sites, one located in the third FNIII domain, and a second located just proximal to the transmembrane domain resulting in the formation of four fragments. The most NH(2)-terminal fragment which is glycosylated with the Lan3-2, Lan4-2, and Laz2-369 glycoepitopes is secreted, and we present evidence which supports a model in which the remaining fragments combine to form a secreted homodimer as well as a transmembrane heterodimer. The extracellular domain of the dimers is mostly made up of the collagen-like PG/YG-repeat domain but also contains 11/2 FNIII domain and the acidic domain. The collagen-like PG/YG-repeat domain could be selectively digested by collagenase and we show by yeast two-hybrid analysis that the intracellular domain of Tractin can interact with ankyrin. Thus, the transmembrane heterodimer of Tractin constitutes a novel protein domain configuration where sequence that has properties similar to that of extracellular matrix molecules is directly linked to the cytoskeleton through interactions with ankyrin.

Differential glycosylation and proteolytical processing of LeechCAM in central and peripheral leech neurons

LeechCAM is a recently described member of the Ig-superfamily which has five Ig-domains, two FNIII-domains, a transmembrane domain, and a cytoplasmic domain. Phylogenetic analysis indicated that LeechCAM is the leech homolog of apCAM, FasII, and vertebrate NCAM. Using a leechCAM-specific monoclonal antibody we show by immunoblot analysis and by Triton X-114 phase separation experiments that in addition to existing in a transmembrane version LeechCAM is likely to be proteolytically cleaved into a secreted form without the transmembrane domain and the intracellular tail. Furthermore, by immunoprecipitation we demonstrate that LeechCAM is glycosylated with the Laz2-369 glycoepitope, an epitope that has been specifically implicated in regulation of axonal outgrowth and synapse formation.

Sequential steps in synaptic targeting of sensory afferents are mediated by constitutive and developmentally regulated glycosylations of CAMs

Sensory afferents in the leech are labeled with both constitutive and developmentally regulated glycosylations (markers) of their cell adhesion molecules (CAMs). Their constitutive mannose marker, recognized by Lan3-2 monoclonal antibody (mAb), mediates the formation of their diffuse central arbors. We show that, at the ultrastructural level, these arbors consist of large, loosely organized axons rich with filopodia and synaptic vesicles. Perturbing the mannose-specific adhesion of this first targeting step leads to a gain in cell-cell contact but a loss of filopodia and synaptic vesicles. During the second targeting step, galactose markers divide afferents into different subsets. We focus on the subset labeled by the marker recognized by Laz2-369 mAb. Initially, the galactose marker appears where afferents contact central neurons. Subsequently it spreads proximally and distally, covering the entire afferent surface. Afferents now gain cell-cell contact, with central neurons and self-similar afferents, but lose filopodia and synaptic vesicles. Extant synaptic vesicles prevail where afferents are apposed to central neurons. These neurons develop postsynaptic densities and en passant synapses are forming. Perturbing the galactose-specific adhesion of this second targeting step causes a loss of cell-cell contact but a gain in filopodia and synaptic vesicles, essentially returning afferents to the first targeting step. The transformation of afferent growth, progressing from mannose- to galactose-specific adhesion, is consistent with a change from cell-matrix to cell-cell adhesion. By performing opposing functions in a temporal sequence, constitutive and developmentally regulated glycosylations of CAMs collaborate in the synaptogenesis of afferents and the consolidation of self-similar afferents.

Gliarin and macrolin, two novel intermediate filament proteins specifically expressed in sets and subsets of glial cells in leech central nervous system

Using monoclonal antibodies, we have identified two novel intermediate filament (IF) proteins, Gliarin and Macrolin, which are specifically expressed in the central nervous system of an invertebrate. The two proteins both contain the coiled-coil rod domain typical of the superfamily of IF proteins flanked by unique N- and C-terminal domains. Gliarin was found in all glial cells including macro- and microglial cells, whereas Macrolin was expressed in only a single pair of giant connective glial cells. The identification of Macrolin and Gliarin together with the characterization of the strictly neuronal IF protein Filarin in leech central nervous system demonstrate that multiple neuron- and glial-specific IFs are not unique to the vertebrate nervous system but are also found in invertebrates. Interestingly, phylogenetic analysis based on maximum parsimony indicated that the presence of neuron- and glial cell-specific IFs in coelomate protostomes as well as in vertebrates is not of monophyletic origin, but rather represents convergent evolution and appears to have arisen independently.

Resistance to type 1 diabetes induction in 12-lipoxygenase knockout mice

Leukocyte 12-lipoxygenase (12-LO) gene expression in pancreatic beta cells is upregulated by cytotoxic cytokines like IL-1beta. Recent studies have demonstrated that 12-LO inhibitors can prevent glutamate-induced neuronal cell death when intracellular glutathione stores are depleted. Therefore, 12-LO pathway inhibition may prevent beta-cell cytotoxicity. To evaluate the role of 12-LO gene expression in immune-mediated islet destruction, we used 12-LO knockout (12-LO KO) mice. Male homozygous 12-LO KO mice and control C57BL/6 mice received 5 consecutive daily injections of low-dose streptozotocin to induce immune-mediated diabetes. Fasting serum glucose and insulin levels were measured at 7-day intervals, and the mice were followed up for 28 days. 12-LO KO mice were highly resistant to diabetes development compared with control mice and had higher serum insulin levels on day 28. Isolated pancreatic islets were treated with IL-1beta, TNF-alpha, and IFN-gamma for 18 hours. Glucose-stimulated insulin secretion in cytokine-treated islets from C57/BL6 mice decreased 54% from that of untreated islets. In marked contrast, the same cytokine mix led to only a 26% decrease in islets from 12-LO KO mice. Furthermore, cytokine-induced 12-hydroxyeicosatetraenoic acid (12-HETE) production was absent in 12-LO KO islets but present in C57/BL6 islets. Isolated peritoneal macrophages were stimulated for 48 hours with IFN-gamma + LPS and compared for nitrate/nitrite generation. 12-LO KO macrophages generated 50% less nitrate/nitrite when compared with C57BL/6 macrophages. In summary, elimination of leukocyte 12-LO in mice ameliorates low dose streptozotocin-induced diabetes by increasing islet resistance to cytokines and decreasing macrophage production of nitric oxide.

Mannose-specific recognition mediates two aspects of synaptic growth of leech sensory afferents: collateral branching and proliferation of synaptic vesicle clusters

The developmental role of carbohydrate markers in the genesis of neuronal networks was studied using leech sensory afferents as a model. Leech sensory afferents express a mannose-containing epitope on their cell surface that is recognized by monoclonal antibody Lan3-2. Previously, the elaboration of sensory arbors in the synaptic neuropil of CNS ganglia was experimentally shown to depend on this mannose marker. Sensory arbors were abolished by perturbing sensory afferents in the intact nervous system with Lan3-2 Fab fragments, a glycosidase, or mannose-BSA. To understand the cytological mechanisms underlying mannose-specific recognition for synaptogenesis, we have now studied the effects of antibody perturbation at the ultrastructural level in the sensory afferent target region. A characteristic signature of a normal sensory afferent is its profuse collateral branching, which, with ongoing development, is replaced by a single widened process, the sensory trunk, which possesses numerous synaptic vesicle clusters. The inhibition of mannose-specific recognition leads to a rapid, major reorganization of different stages of sensory afferent growth. Collateral branches at the distal growing region are reduced three- to fourfold. The pruned axons grow at an accelerated rate. Developmentally older sensory trunks experience a threefold reduction in synaptic vesicle clusters. These responses suggest that depriving sensory afferents of mannose-specific recognition aborts their synaptogenesis and causes them to resume behavior typical of tracking through axonal tracts. The current findings also suggest that the mannose marker, by promoting both collateral branching andthe proliferation of synaptic vesicle clusters, plays a critical role in two stages of sensory afferent synaptogenesis.

Cholesterol and its derivatives, are the principal steroids isolated from the leech species Hirudo medicinalis

Steroids were isolated from the blood-sucking leech species Hirudo medicinalis and their structure was studied with one- and two-dimensional NMR spectroscopy (DQF-COSY and HMQC), GC-MS and ESI-MS spectrometry. Fractionating leech lipid using silicic acid chromatography led to the isolation of cholesterol in an early chloroform-eluted peak. Only minor traces of cholest-4-en-3-one, 4 beta-methylcholesterol, and sitosterol were present. The subsequent acetone-eluted fraction contained steroidtriols that were further purified by preparative TLC; these included cholest-7-ene-3,5,6 triol, cholest-4,7-diene-3,6,15 triol and to a lesser amount, cholestane-3,5,6 triol. A developmental study on cholesterol content in the leech showed that it is also the principal steroid in embryonic and freshly hatched leeches prior to feeding. The abundance of cholesterol, comprising approximately 5% of the total leech lipid, suggests that H. medicinalis, a blood sucking leech, has adapted itself fully to its mammalian host in terms of its steroid content. It remains to be seen whether lipids are directly transferred from the host to the parasite or whether leeches have evolved mechanisms to synthesize their own steroids.

Structural analysis of leech galactocerebrosides using 1D and 2D NMR spectroscopy, gas chromatography-mass spectrometry, and FAB mass spectrometry

Cerebrosides were isolated from the leech species, Hirudo medicinalis, and purified to homogeneity by silicic acid chromatography, followed by preparative thin-layer chromatography. Their structure was determined by spectroscopic and chemical methods. 1D and 2D 1H NMR spectroscopy, DQF-COSY and HMQC indicated that the head group consists of a single galactose residue in the beta configuration. The galacto configuration was determined by the characteristic chemical shift, the spin-spin splitting and the multiplicity of the characteristic resonance of its equatorial H-4 proton, as well as by the splittings of the other ring protons. GC, GC-MS and fast-atom-bombardment mass spectrometry studies indicated that C24:0 and C22:0 are the major saturated fatty acid species. Unsaturated fatty acids present were C25:2, C27:2, C27:3, C28:3, C29:3, C30:3, C33:3. GC-MS indicated the presence of hydroxylated C27:2 and one other unidentified hydroxylated fatty acid. The cerebroside contained an unusual polyunsaturated sphingosine analogue, namely 2-amino-1,3-dihydroxydocsatriene.

Leech photoreceptors project their galectin-containing processes into the optic neuropils where they contact AP cells

We characterized a subset of leech sensory afferents, the photoreceptors, in terms of their molecular composition, anatomical distribution, and candidate postsynaptic partners. For reagents, we used an antiserum generated against purified LL35, a 35 kD leech lactose-binding protein (galectin); monoclonal antibody (mAb) Lan3-2, which is specific for a mannose-containing epitope common to the full set of sensory afferents; and dye injections. Photoreceptors differ from other types of sensory afferents by their abundant expression of galectin. However, photoreceptors share in common with other sensory modalities the mannose-containing epitope recognized by mAb Lan3-2. Photoreceptors from a given segment project their axons directly into the CNS ganglion innervating the same segment. They assemble in a target region, the optic neuropil, which is separate from the target regions of other sensory modalities. They also extend their axons as an optic tract into the connective to innervate optic neuropils of other CNS ganglia, thereby providing extensive intersegmental innervation for the 33 CNS ganglia comprising the leech nerve cord. Because of its intimate contact with the optic neuropil, a central neuron, the AP effector cell, is a strong candidate second order visual neuron. In confocal images, the AP cell projects its primary axon for about 100 microns alongside the optic neuropil. In electron micrographs, spines emanating from the axon of the AP cell make contact with vesicle laden nerve terminals of photoreceptors. Leech photoreceptors and their second order visual neurons represent a simple visual system for studying the mechanisms of axonal targeting.

Sequential steps in axonal targeting are mediated by carbohydrate markers

Mannose and hybrid/complex-type oligosaccharides serve as markers for both the full set of peripheral sensory afferent neurons in the leech and also for disjoint subsets of these neurons. We have shown that these various surface carbohydrates play crucial roles in the multistep process by which afferents meet their synaptic partners in the central nervous system (CNS). The carbohydrate marker common to all these afferents allows their projections (which are fasciculated as they enter the CNS) to disperse and search out target regions. Carbohydrate markers specific for subsets of these afferents subsequently allow each subset to consolidate the position of its projections in appropriate regions of the CNS where it contacts its synaptic partners.

Kinetics of the inhibition of axonal defasciculation and arborization mediated by carbohydrate markers in the embryonic leech

We studied carbohydrate interactions that mediate the targeting of sensory afferents in the synaptic neuropil of segmental central nervous system (CNS) ganglia in the embryonic leech. First, we determined the rate of sensory afferent development in vivo, and then we devised a culture system that permits the normal patterning of their projections in the CNS and PNS to proceed at 92% the normal rate. Using this in vitro system, we analyzed the mannose-specific recognition that mediates the defasciculation and arborization of sensory afferents in the CNS neuropil after they have tracked through peripheral nerves as a tight axon bundle. Sensory afferent defasciculation and arborization in the neuropil were inhibited by culturing embryos in Fab fragments directed against the mannose-containing surface epitope of sensory afferents. We demonstrate that the rate at which separately extending axons or their branches are lost from the neuropil can be modeled by a first-order decay process. These kinetic studies indicate that the loss of each separately extending axon or branch is an independent event. This suggests that sensory afferent projections extend autonomously across the target region in the search of their appropriate postsynaptic partners.

Targeting of neuronal subsets mediated by their sequentially expressed carbohydrate markers

The targeting of sensory afferent neurons in the leech CNS occurs in two discrete steps that are mediated via different carbohydrate recognitions, as shown by molecular perturbations of cultured embryos. A constitutive carbohydrate marker that is generic to all of these neurons mediates their initial defasciculation and arborization across the entire target region via mannose-specific recognition. Subsequently, two subsets of these same neurons can be differentiated by their expression of other markers that are located on hybrid or complex type carbohydrate chains. These developmentally regulated carbohydrate markers then mediate the target assembly of their respective neuronal subsets into discrete subregions. Thus, by performing opposing functions in a temporal sequence, constitutive and developmentally regulated carbohydrate markers collaborate in the targeting of neuronal subsets in the CNS.

Distribution of carbohydrate epitopes among disjoint subsets of leech sensory afferent neurons

Carbohydrate recognition plays an important role in the development of normal projections of sensory afferent neurons in the leech CNS. Four different carbohydrate epitopes are expressed by sensory afferents on their 130 kDa surface proteins: all sensory afferents share a common carbohydrate epitope (CE0) that helps them to enter and project diffusely across the synaptic neuropil; a restricted expression of three other carbohydrate epitopes (CE1, CE2, and CE3) serves to distinguish three subsets of sensory afferents. We examined the subsets of sensory afferents defined by their subset carbohydrate epitopes in the leech lip, skin, gut, and CNS. We established that the CE1, CE2, and CE3 subset epitopes define disjoint subsets of neurons by double labeling sensory afferents with monoclonal antibodies for different pairs of subset epitopes. We found that CE2 and CE3 afferents populate the lip and skin, but not the gut, and that these two subsets of sensory afferents have convergent projection patterns in the CNS. We found that CE1 afferents populate the gut and skin, but not lips; furthermore, their CNS projections diverge from those of CE2 and CE3 afferents. Our data fit the hypothesis that these carbohydrate epitopes are related to sensory modality of afferent subsets.

Carbohydrate-binding proteins in the leech: I. Isolation and characterization of lactose-binding proteins

Three lactose-binding proteins with apparent molecular masses of 16, 35, and 63 kDa [leech lectin 16, 35, and 63 (LL,16, LL35, and LL63, respectively)] were isolated from leech membranes. Polyclonal antibodies raised against LL35 cross-reacted with LL16 and LL63, indicating that all three lectins were immunologically related. These leech lectins, however, can be subdivided into two groups based on their tissue distributions and binding affinities for galactose derivatives. LL16 and LL35 are endogenous to the leech's CNS, whereas LL63 is only present in peripheral organs. LL16 and LL35, found in the CNS, bind both the alpha and beta anomers of methylgalactose, whereas the peripheral lectin LL63 binds only the beta form. LL35 and LL63 also differ in their binding affinities for galactosamine and N-acetylgalactosamine. The binding activity of LL35 was calcium independent and active over a wide pH range. Triton X-100 and 2-mercaptoethanol were necessary to recover LL35 binding activity during extraction. These characteristics strongly suggest that LL35 is another member of the calcium-independent galactose/lactose-specific lectins previously described in vertebrates and recently demonstrated in sponges and nematodes. Because a single leech expresses up to 100 micrograms of LL35, this leech lectin is readily amenable to structural and functional analysis.

Carbohydrate-binding proteins in the leech: II. Lactose-binding protein LL35 is located to neuronal and muscle subsets and all epithelial cells

Leech lectin 35 (LL35) is a calcium-independent galactoside-binding protein with a molecular mass of 35 kDa and binding properties similar to those of calcium-independent, galactose-specific lectins found in vertebrates, sponges, and nematodes. LL35 was initially isolated from membranes of the leech CNS; however, large amounts of this lectin were also extracted from the rest of the leech. Using affinity-purified antibodies to LL35, we report the immunocytochemical localization of LL35 in adult and embryonic leech. LL35 is developmentally regulated in epithelial, neuronal, and muscle tissue but is absent from glia. During embryogenesis, LL35 is highly expressed by a subset of sensory neurons, weakly expressed in epithelial cells, and absent from muscle. In the adult, LL35 is still present on the same sensory neurons but has become more abundant in epithelial cells lining the CNS and peripheral organs. LL35 also appeared on a muscle cell specifically located in the CNS but remained absent from peripheral muscle. The developmentally regulated distribution of LL35 in epithelial cells, neurons, and CNS muscles suggests a multifunctional role for this lectin with respect to these different cell types.

Different forms of 130 kD connective tissue protein are specific for boundaries in the nervous system and basement membrane of muscle cells in leech

The nervous system and muscle tissue of the leech express two different organ-specific forms of connective tissue protein. The nervous system-specific form appears in regional boundaries separating cell bodies, axonal tracts and areas of the neuropile during late embryogenesis. In contrast, the muscle-specific form appears earlier during development in the basement membrane of muscle cells. In extraction experiments both forms behave like extracellular matrix proteins and because of their molecular weight, are considered members of a group of cell type-specific 130 kD proteins (leech gp130s). However, the two forms differ in their posttranslational modification. As determined by Con A and lentil lectin affinity chromatography, only the nervous system-specific, but not the muscle-specific form, has fucosylated and high mannose N-linked carbohydrates. These differences in the developmental onset and glycosylation suggest that nervous system-specific and muscle-specific connective tissue proteins are regulated differently and participate in different molecular interactions.

A mannose-specific recognition mediates the defasciculation of axons in the leech CNS

We are studying a mannose-specific recognition mediating the projection of axons in the synaptic neuropil of the embryonic leech CNS. A functional class of neurons, the sensory afferents, can be distinguished by a mannose-containing epitope that is asparagine-linked to a 130 kDa surface protein and is reactive with the monoclonal antibody Lan3-2. Sensory afferents project as a tightly fasciculated bundle through peripheral nerves but, upon arriving in the CNS, defasciculate into the synaptic neuropil. This defasciculation allows the previously bundled sensory afferents to form an arborization in the synaptic neuropil. Three lines of experimental evidence indicate that the defasciculation is mediated by the sensory afferent's mannose-containing Lan3-2 epitope. The defasciculation is inhibited (1) by blocking the Lan3-2 epitope with Lan3-2 Fab fragments, (2) by cleaving the asparagine-linked carbohydrate moieties from surface proteins with the glycosidase N-glycanase, and (3) by competing for a putative mannose-binding protein with the neoglycoprotein mannose-BSA [albumin, p-aminophenyl alpha-D-mannopyranoside (26 mol monosaccharide/mol albumin)]. In addition to inhibiting the defasciculation, the three perturbation reagents also elicited the refasciculation of axons that had defasciculated prior to their application. These three different experimental approaches provide strong evidence that carbohydrate recognition regulates the projections of sensory afferents in the leech synaptic neuropil. Carbohydrate interactions therefore can play a major role in regulating the neuronal architecture in the CNS.

The segmentation of the leech nervous system is prefigured by myogenic cells at the embryonic midline expressing a muscle-specific matrix protein

In the leech, adult muscle cells and embryonic mesodermal/myogenic cells express the cell-type-specific Laz 10-1 epitope on extracellular matrix-associated proteins. Using this muscle-specific epitope as a marker, we found the following correlations between the development of identifiable myogenic cells at the embryonic midline and the segmentation of the leech CNS into 32 reiterative ganglia. (1) During the production of mesodermal and ectodermal stem cells, cell bodies of midline myogenic cells create 32 anterior-posterior intervals along the midline of the embryonic germinal plate. The mesoblasts then rearrange themselves into 32 somites whose spacing follows the intervals between the midline myogenic cell bodies. (2) Bilateral segmental zones of myogenic differentiation originate in juxtaposition to the midline myogenic cells. (3) The first two types of muscle precursors develop from midline and adjacent bilateral myogenic cells; they are the precursors of the CNS muscles and of three groups of ventral blood sinus muscles. These two types of muscle precursors demarcate the boundaries of the territory within which neuroblasts proliferate and coalesce into segmental hemiganglionic primordia: Cell bodies of muscle precursors, like cornerstones, demarcate the anterior and posterior borders of the hemiganglionic primordia; their longitudinal processes surround the expanding hemiganglionic primordia on the medial, lateral, dorsal, and ventral aspect. The contours of muscle precursors and midline myogenic cells are sharply delineated by immunohistochemical staining of the Laz 10-1 epitopes. In contrast, undifferentiated mesoblasts are surrounded by diffuse layers of stained epitopes, which are expressed at fluctuating levels. Because elevated levels of this matrix epitope are associated with mesodermal/myogenic cells undergoing morphogenetic rearrangements, it may participate in the molecular mechanisms underlying the segmentation of the nervous system.

The specificity of 130-kDa leech sensory afferent proteins is encoded by their carbohydrate epitopes

From early development through adulthood in the leech, sensory afferents, glial cells, and connective tissue express different epitopes located on a group of 130-kDa glycoproteins. The sensory epitope [reactive with monoclonal antibody (mAb) Lan3-2] is shared by the peripheral sensory afferents of different sensory modalities. In contrast, three other immunocytochemically distinct epitopes (reactive with mAbs Laz2-369, Laz7-79, and Laz6-212) differentiate these sensory afferents according to their sensory modalities. The glial epitope (mAb Laz6-297) is expressed on all macroglial processes, and the connective tissue epitope (mAb Laz9-84) is located on connective tissue surrounding the CNS, as well as in the peripheral tissues. The hydrophilic-hydrophobic nature of the 130-kDa sensory afferent and glial proteins was determined by phase separation with Triton X-114 and hypoosmotic extraction. They behave as peripheral membrane proteins. Deglycosylation of 130-kDa glycoproteins with N-Glycanase or preincubation of their respective mAbs with alpha-methylmannoside showed that the sensory epitope contains mannose, whereas the modality epitopes are of an undefined carbohydrate character. Immunoprecipitation and a peptide mapping experiment confirmed the existence of four distinct sensory afferent epitopes. Previous studies provided evidence that the mannose-containing Lan3-2 epitope mediates normal sensory afferent growth in the synaptic neuropile. We, therefore, postulate that the carbohydrate epitopes on sensory afferent glycoproteins participate in synapse formation.

Segregation of afferent projections in the central nervous system of the leech Hirudo medicinalis

Sensory axons originating in peripheral tissues converge onto each segmental ganglion in the central nervous system (CNS) of the leech, where they segregate into well-defined regions of the synaptic neuropil. Here we report on several aspects of the molecular and anatomical organizations of these afferent projections that bear upon the hypothesis that surface markers are involved in organizing these axons as they grow into the CNS. First, we show that the distribution of some surface markers in the adult is restricted to axons of peripheral origin and is not present on the neighboring axons of central neurons. Second, we demonstrate that the number of afferents increases postembryonically as the leech increases in size, suggesting that at least some of the cues employed by afferent axons to grow to appropriate central targets must be present throughout the life of the animal. We then show, using anterograde axonal tracing and immunohistochemistry, that there is both convergence and divergence of afferent axons into highly specific regions of the neuropil. Lastly, we examine the distribution of surface markers present on different subsets of afferents and show that axons having one type of marker segregate from those having the second type. Our results, considered together with previous observations in this system, provide new clues about the organization of afferent projections in the nervous system of the leech. They also suggest how a relatively small number of molecular markers might mediate fiber-fiber interactions to organize afferent axons as they grow into the CNS.

Carbohydrate epitopes involved in neural cell recognition are conserved between vertebrates and leech

We are reporting on the evolutionary conservation of carbohydrate epitope families from vertebrate to leech. 1) The sulfated L2/HNK-1 carbohydrate epitope (Abo T, Balch CM (1981): J Immunol 127:1024-1029; Kruse J, Mailhammer R, Wernecke H, Faissner A, Timpl R, Schachner M (1984): Nature 311:153-155) is detected on glycoproteins of leech neurons using monoclonal antibodies (mAbs) L2 (336) and HNK-1. 2) Three rat mAbs, L3, L4, and L5, bind to leech nerve and muscle. The L3, L4, and L5 epitopes are localized to a group of mannosidic leech glycoproteins originally identified through mAbs Lan3-2 (Hogg N, Flaster M, Zipser B (1983): J Neurosci Res 9:445-457 and Laz6-189 (McRorie JW III, Zipser B (1988): "Cell Culture Approaches to Invertebrate Neuroscience." London: Academie Press, pp 33-52. MAb Lan3-2, which binds to a mannosidic epitope of the 130 kD sensory protein, has recently been shown to perturb the penetration of sensory afferents into the synaptic area of the central neuropile (Zipser B, Morell R, Bajt ML (1989): Neuron 3:621-630). The L3, L4, and L5 mAbs have been described to recognize different mannosidic epitopes on glycoproteins, some of which have been identified as neural cell adhesion molecules, and on astrocyte-specific proteoglycan from mouse brain (Kücherer A, Faissner A, Schachner M (1987): J Cell Biol 104:1597-1602; Fahrig T, Schmitz B, Weber D, Kücherer-Ehret A, Faissner A, Schachner M (1990): Eur J Neurosci 2:153-161; Streit A, Faissner A, Gehrig B, Schachner M (1990): J Neurochem In Press). The superposition of five different mannosidic epitopes on the axons of sensory afferents suggests complex, concerted participation of mannosidic epitopes in neuronal pathfinding and target recognition.

Expression of surface glycoproteins early in leech neural development

Cell migration and axon growth during neural development rely upon cell-cell and cell-matrix interactions mediated by surface glycoproteins. The surface glycoprotein recognized on leech neurons by monoclonal antibody Lan3-2 has previously been implicated in the process of axon fasciculation during regeneration in adults. In adult leeches, Lan3-2 binds to a carbohydrate epitope of a 130 kD protein. The present study demonstrates that in embryos the antibody binds to the same carbohydrate epitope of glycoproteins with molecular weights of 130 kD and higher. As a first step in evaluating a possible role of the Lan3-2 glycoprotein or the cells that express it during neural development, we determined its distribution in the developing nervous system of the leech Hirudo medicinalis. In embryos, Lan3-2 epitope is expressed on fasciculated sensory afferents and it appears on the cell bodies before neurite outgrowth. The sensory fibers appear rostrally by embryonic day 10, less than halfway through development. Earlier, by 7 days of development at 20 degrees C, Lan3-2 binds to previously undocumented cell types: (1) cells appearing along the embryonic midline and (2) a cluster of cells located at the rostral edge of the germinal plate. These cells only transiently express this antigen and are present at critical left-right and rostrocaudal boundaries during a period of cell proliferation, movement, and migration that produces the nervous system. Thus the Lan3-2 surface glycoprotein or the cells expressing it are candidates for involvement in axon fasciculation, cell migration, and directed axonal growth.

Defasciculation as a neuronal pathfinding strategy: involvement of a specific glycoprotein

Leech sensory afferents change their growth behavior as they enter the CNS. Arriving from the periphery in fasciculated tracts, they abruptly defasciculate and expand into diffuse trees before reassembling into four distinct central tracts. In the organ-cultured germinal plate, growing sensory afferents were incubated with monovalent Fab fragments of the Lan3-2 antibody, which recognizes a 130 kd sensory neuron protein by its mannose epitope. Very low concentrations of Lan3-2 (6 and 12 nM) specifically inhibited the central defasciculation of sensory afferents, which then continued growing as a single tract. In contrast, monoclonal antibody Lan3-6, which binds to an internal sensory antigen, failed to yield the same effect. These observations suggest that this sensory neuron 130 kd surface glycoprotein participates in a developmentally significant heterophilic interaction specific for the CNS.

Glial processes, identified through their glial-specific 130 kD surface glycoprotein, are juxtaposed to sites of neurogenesis in the leech germinal plate

Glial processes, bearing a unique 130 kD surface protein, are located at key sites of morphogenic movement and neuronal differentiation in the leech germinal plate. A midline glial fascicle resides at the primary axis of embryonic symmetry, alongside which teloblasts move as they generate their bandlets of stem cells. The n-bandlets straddle the midline glia and are known to produce most of the central neuroblasts. The midline glia then defasciculates as neuroblasts begin to aggregate into neuromeres. The defasciculated processes expand into these neuromeres, molding the future central neuropile. Neuroblasts will initiate primary axons toward the midline glia. As the neuromeres mature, midline glial process thin out to demarcate the orientation of the future connectives, which are the major longitudinal axon tracts along the midline. Next, segmental but still primordial glia appear in the neuromeres. Initially, they also project longitudinally, then transversely, demarcating the other two major axonal pathways--the central commissures and peripheral roots. Finally, macroglial processes proliferate as massive axon growth invades the central and peripheral nervous system. Thus, glial processes with different developmental histories accompany different aspects of leech neurogenesis. In other systems, glia have been shown to promote the differentiation and the guidance of neurons. It remains to be seen whether the glial-specific 130 kD protein is a receptor mediating these typical glial functions in the leech germinal plate.

The opiate receptor: a single 110 kDa recognition molecule appears to be conserved in Tetrahymena, leech, and rat

We compared the molecular nature of the rat brain opiate receptor with that of the invertebrate leech, Haemopis marmorata, and the protozoan, Tetrahymena, in order to examine the issue of apparent receptor heterogeneity with respect to biochemical structure. A binding study with rat brain membrane verified that [125I]beta-endorphin [( 125I]beta E), a broad specificity ligand, is displaced by the antagonist (-)-naloxone, but not the inactive stereoisomer (+)-naloxone; agonists considered prototypes for mu, delta, and kappa opiate receptors all displayed stereospecific binding displacement. For SDS-PAGE analysis of the opiate receptor [125I]beta-endorphin was covalently affixed to its recognition molecule with the cross-linking reagent DSS. Primary reaction products occur at 110, 58/55, and 29 kDa. Cross-linking products of all 3 molecular weights are effectively reversed by opiate ligands, regardless of their mu, delta, or kappa specificities. Peptide mapping studies in SDS gels, using limited proteolysis, showed that the 110 kDa band can be digested into 58 and 29 kDa fragments and the 58 kDa band into a 29 kDa fragment. Additional smaller molecular weight fragments were generated from the 110, 58/55, and 29 kDa bands which shared their molecular weights. Two possible explanations for the extensive sequence homology between the three major cross-linking products are: (1) the 110 kDa species is the opiate receptor, and the 58 and 29 kDa species are proteolytic fragments; and (2) one of the lower molecular weight species is the opiate receptor, and adjacent receptors are aggregated into the 110 kDa complex through cross-linking.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification and characterization of the opiate receptor in the ciliated protozoan, Tetrahymena

Tetrahymena, a ciliated protozoan, is a highly specialized, differentiated eukaryotic organism. It is known to possess many informational substances, including beta-endorphin (beta E). We wished to investigate the possibility that this organism possesses a functional opiate receptor which might be similar to the well-characterized opiate receptor in the rat brain. Binding assays using both living cells and membrane preparations, verified stereospecific, saturable, reversible 125I-beta E binding. This binding was displaceable by various opiates chosen to represent each of the putative opiate subtypes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of a disuccinimidyl suberate cross-linked 125I-beta E-receptor complex revealed a pattern of bands which consistently included bands at 110, 58-55, and 29 kDa. These bands, which were all displaceable by the classical antagonist, naloxone, as well as by other opiates, are thought to be prototypic for various opiate receptor subtypes. Limited proteolysis in SDS-PAGE showed that the 110 kDa band could be fragmented into 58-55 and 29 kDa bands and that the 58 kDa band could generate a 29 kDa fragment. The limited digest fragments of the 110, 58-55 doublet and 29 kDa bands were remarkably similar to those generated from the rat brain receptor. Analytical isoelectric focusing of digitonin solubilized 125I-beta E-receptor complexes showed the isoelectric points (pI) from both the rat and Tetrahymena were identical (pI 4.6). Chemotactic experiments with the intact Tetrahymena, demonstrated that these unicellular animals migrated toward a 10(-9) M beta E gradient. Chemotaxis was blocked by (-)-naloxone but not (+)-naloxone, suggesting a stereospecific opiate receptor-mediated response. We conclude that Tetrahymena possesses a functional opiate receptor (recognition molecule) very similar to the opiate receptor of the rat brain.

Vasoactive intestinal peptide receptors in rat spleen and brain: a shared communication network

The binding sites for [125I]-vasoactive intestinal polypeptide (125I-VIP) in rat spleen and brain were localized using autoradiography. High affinity VIP receptors are present in rat spleen, and competition studies reflect structure-activity relationship typical of VIP receptors elsewhere. In spleen, specific binding of 125I-VIP occurs on red pulp and, most abundantly, on the periarteriolar lymphoid sheath (PALS) of white pulp. Unlabeled VIP competes for binding to both red pulp and white pulp, whereas secretin displaces binding to PALS more potently than to red pulp. This indicates that expression of VIP and/or secretin type receptors is limited to T lymphocytes of white pulp. In red pulp, VIP receptor bearing cells probably are monocytes/macrophages since this is the most abundant red pulp cell type. In the brain, VIP receptors are widely distributed with the highest densities occurring in "sensory" areas. Receptors are abundant in the olfactory bulb, thalamic nuclei, several cranial nuclei and the area postrema. High levels of 125I-VIP binding occurred on inner walls of blood vessels of the brain and spleen. The distribution patterns of receptors for "VIP-ergic signals" in brain and lymphoid tissue indicate interrelatedness of the two organ systems. This may serve as one biochemical rationale for a bio-psycho-social view of health and disease.

Cell death during gangliogenesis in the leech: bipolar cells appear and then degenerate in all ganglia

The bipolar cells can be recognized very early during gangliogenesis in the leech central nervous system by their expression of antigens that are recognized by the monoclonal antibody Laz1-1. They are the first cells to express these antigens, which are later shared with a distinct set of other cells in the leech nervous system. Their processes extend several segments rostrally and caudally along the forming interganglionic connective nerves; they are first found in anterior segments and gradually appear in more posterior ones over the course of 2-3 d. At about the time bipolar cells appear in the neuromeres of the tail ganglion, those in the most anterior segmental ganglia begin to degenerate. Degeneration proceeds caudally over the next 3 d, until all bipolar cells have disappeared. Bipolar cells are, thus, members of that class of cells that exists for only a short period in neurogenesis and then presumably disappears once its functions are no longer required. These cells' morphology and appearance at the earliest stages in the formation of the interganglionic connective nerves are suggestive of a role in the establishment of these longitudinal pathways in the leech CNS.

A group of related surface glycoproteins distinguish sets and subsets of sensory afferents in the leech nervous system

The distribution of 4 surface glycoproteins on axons of peripheral neurons was studied in the leech Hirudo medicinalis through monoclonal antibodies. All 4 glycoproteins have a similar molecular weight of 130 kDa. Immunohistochemical localization of these glycoproteins on tissue sections of nerves and neuropil reveals tracts of afferent axons organized as nested sets. Their distribution suggests a possible role for these molecules in mediating axon fasciculation.

Regeneration of afferent axons into discrete tracts within peripheral nerves in the leech

We have analyzed the pathway followed by regenerating afferent axons in peripheral nerves of the leech Hirudo medicinalis by anterograde labeling with horseradish peroxidase. We show that axons are able to reestablish appropriate pathways following a lesion (crush) which greatly disrupts the organization of the nerves. Our results are consistent with a pathway selection mechanism involving axon surface markers which are retained on the distal stumps of crushed axons.

The macroglial cells of the leech are molecularly heterogeneous

Monoclonal antibodies derived from fusions employing either whole leech nerve cords or fractionated proteins (gel bands) bind to the macroglial cells of the nerve cord. Three different antibodies bind to either one, two, or three of the four macroglial cell types in the leech CNS, serving as markers and showing that these four cell types, which differ primarily by anatomical position, all differ molecularly as well. Conventional microscopy confirms the existence of a novel macroglial cell type first noted because it binds antibody. Western (immunoblot) blot analyses demonstrate a polypeptide antigen of 77 kD in the macroglial cells of the connectives and a 130-kD polypeptide antigen associated with the macroglial cells of the connectives, of the root nerves, and of the ganglionic neuropil. The extensive molecular heterogeneity of leech neurons demonstrated by monoclonal antibody techniques is shared by macroglia.

Development of segmental differences in the pressure mechanosensory neurons of the leech Haementeria ghilianii

Using a monoclonal antibody specific for the pressure mechanosensory neurons (P cells) of the leech Haementeria ghilianii, we have examined the segmental differences between P cells in the adult nerve cord, as well as the development of these differences during embryogenesis. The standard segmental ganglion contains two pairs of P cells of about the same size and staining intensity. The sex ganglia appear to be missing the P cells that normally innervate ventral skin, and ganglia 20 and 21 have much smaller ventral P cells than most segments. The pattern of P cells in the head and tail ganglia also differs slightly from that of the standard ganglia. During embryogenesis, when the neurons are first stained by the antibody, there are two pairs of P cells of equal size in each segmental ganglion. Obvious segmental differences arise subsequently, modifying an initially identical set of cells.

Probing structural homologies in cell-specific glycoproteins in the leech CNS

Three monoclonal antibodies (mAbs) raised against the leech CNS recognize surface antigens on small sets and subsets of neurons or on glial cells. On immunoblots, they all recognize proteins of 130 kDa molecular weight. In addition, they each bind up to several different lower molecular weight forms. The 130 kDa polypeptides recognized by these mAbs are not major proteins on Coomassie blue-stained gels. They behave as glycoproteins on lentil lectin columns but are not major Concanavalin A-binding molecules. These molecules therefore represent a group of lower abundance, cell-type-specific antigens. Structural relationships between these antigens were explored using immunoprecipitation. The glial cell antigen was immunopurified, however, a fraction of the neuronal antigens co-precipitate. The co-precipitation of neuronal antigens raises the possibility that different neuronal antigenic determinants are carried on the same protein molecule. Such a protein may be modified to carry either one or both neuronal determinants, and could serve as a tag to physiologically delineate subsets of neurons nested within larger neuronal sets.

Antibody staining reveals novel aspects of segmentation within the leech central nervous system

The leech is a segmented annelid with a well characterized central nervous system. In this report, we use antibodies to map the distribution of neurons confined to selected segmental ganglia in the mud leech Haemopis marmorata. The distribution of these neurons suggest 3 novel aspects of segmentation in the leech nervous system: (1) neurons are assigned to even-numbered ganglia through a mechanism which effectively counts through the leech segmental body plan by units of 2, (2) neurons are assigned to ganglia 7 and 14 through a mechanism which effectively counts in units of 7 and (3) neurons are assigned to the 2nd and 4 fused head ganglia and to the 2nd of 21 unfused midbody ganglia through a mechanism which effectively counts units from the origin of these 2 ganglionic series. These 3 hypothetical counting mechanisms divide the central nervous system (CNS) into supersegmental units. Neurons used to define these supersegmental units have been injected with tracer and identified as interganglionic interneurons. Competitive interactions among embryonic precursors of these neurons may directly eliminate their homologs from intervening ganglia, and thus sculpture supersegmental patterns into the mature nervous system.

Varicosity-associated antigens define neuropile subfields in the leech central nervous system

A panel of twelve monoclonal antibodies raised against homogenates of leech nerve cords and four polyclonal antisera raised against purified neurotransmitters were used to label varicosities immunocytologically in the central neuropile of leech segmental ganglia. These immunoreactive varicosities occur in distinct patterns, some of which have a simple geometry. Three antibodies label immunoreactive varicosities distributed in a single dorsoventrally-oriented plane, two label varicosities distributed in lateral hemi-neuropiles (leaving void a central cephalocaudal passageway), and five label varicosities distributed throughout the neuropile. Six antibodies tested label varicosities across leech species, and five of these varicosity populations are distributed in patterns conserved across leech species. Immunocytologically-defined neuropile subfields do not correspond with previously identified histological and ultrastructural features of leech segmental ganglia. Analysis of immunocytologically-defined subfields is extended to include identification of sets of neurons which appear to project into these subfields, and to include an intracellular characterization of one of these neuron sets.

The embryonic development of peripheral neurons in the body wall of the leech Haemopis marmorata

The appearance of peripheral neurons within the skin during embryonic development of the leech is described. These neurons were labeled using a monoclonal antibody, Lan3-6, which recognizes antigens in both the cell body and the axons of these cells. Within the 5 annuli that are found in each midbody segment, peripheral neurons first label in the middle and last in the most anterior and posterior ones. In each annulus, the number of cells labeled is initially 4 and increases as development proceeds. By the end of embryogenesis, all annuli show approximately equal numbers of Lan3-6 labeled neurons. The development of peripheral neurons in the skin of the rear sucker is also described.

Generating monoclonal antibodies against excised gel bands to correlate immunocytochemical and biochemical data

Two MAbs against fixed leech CNS which bind the nociceptive neurons, either the complete set or the lateral subset, yield bands on immunoblots of SDS acrylamide gels. When one of these bands is excised from a gel and used as immunogen. MAbs showing histological and biochemical properties similar to the original mAbs are obtained.

The expression of antigens by embryonic neurons and glia in segmental ganglia of the leech Haemopis marmorata

Monoclonal antibodies (mAbs) raised against adult leech nervous systems were screened on embryos of the leech Haemopis marmorata in order to determine when in development specific antigens are first expressed and the order in which they are expressed by different cells or tissues. Three of the mAbs produced by Zipser and McKay (Zipser, B., and R. McKay (1981) Nature 289: 549-554) were screened: Lan3-1, Lan3-5, and Lan3-6. Each mAb shows a different pattern of labeling in the adult leech nerve cord (Zipser, B. (1982) J. Neurosci. 2: 1453-1464). The embryonic stages studied were from 5 days after egg deposition to 30 days (emergence from the cocoon). The pattern of labeling was assayed in whole mounts using horseradish peroxidase-conjugated second antibodies. The principal results are as follows. (1) Antigens recognized by Lan3-5 are first expressed by the glia of the roots of the anterior segmental ganglia at 6 to 7 days, several days later by the interganglionic connective glia, and near the end of embryonic development by ganglionic neurons. An anterior to posterior temporal gradient is observed in the expression of these antigens. In addition, Lan3-5 also labels the protonephridia and nephridia from early development onward. (2) Antigens recognized by Lan3-6 are first expressed by a pair of neurons in each segmental ganglion and later in development by additional neurons. By the time of emergence, however, only about half of the neurons that label in the adult have done so, implying that some neurons express these antigens postembryonically. Labeling with Lan3-6 is first seen in neuronal somata and only later in neuronal processes. (3) Antigens recognized by Lan3-1 and expressed by segmentally specific neurons in ganglia 5 and 6 are not detectable during embryonic development, but are so at early postembryonic stages. Thus, these three mAbs provide an approach to study different aspects of the development of the leech nervous system, specifically the relation between glial and neuronal differentiation and the genesis of segmentally specific phenotypes.

Cross-reactivities of monoclonal antibodies between select leech neuronal and epithelial tissues

Three monoclonal antibodies, originally studied because of their neuron-specific staining in the leech central nervous system, are characterized further here, both immunocytochemically and biochemically, with Western blot staining using the central nervous system and peripheral tissues. The three antibodies react both with neurons and select epithelial tissue in the central nervous system, gut, and penis. Antibody Lan3-8 reacts with neurons in the nerve cord and gut but with epithelial cells in the penis; it binds to a 65K molecule in all three tissues. Lan3-2 and Laz2-369 are considered as a related pair because in the central nervous system the former stains all (four) and the latter generally only half (two) of the neurons in a standard midbody ganglion responding to nociceptive stimulation. In the gut, both antibodies label patches of epithelial cells and Laz2-369 stains a previously unknown type of gut neuron. While a given antibody stains different bands in gut and central nervous system immunoblots, comparing the bands of both antibodies for the same tissue extract makes it apparent that there are similarities in the molecular species that both antibodies recognize. For each monoclonal antibody, the histologically identified tissue antigens need to be correlated with proteins identified on Western blots. Of particular interest are the broad 130K bands to which Lan3-2 and Laz2-369 bind. The question is raised whether the molecular species in these bands represent a family of proteins that serve a specific nociceptive cell function.

Complete distribution patterns of neurons with characteristic antigens in the leech central nervous system

Monoclonal antibodies were used to map the distribution of neurons in the leech which contain a particular antigen. This technique reveals the genetically determined variation in cell body distribution along the nerve cord. In addition, antibodies also reveal developmental deviations, such as the occurrence of supernumerary cell bodies. Three antibodies that bind either to single types or small sets of different neurons are used to construct complete distribution patterns of antigenically related cells. Three other antibodies are used to create cell body distribution maps of antigenically homologous primary mechanosensory cells responding to noxious or pressure stimulation which form a subset of the cells stained by the antibody. Furthermore, antibodies against the pressure cells helped in the location of two different specific antigens for the same identified nerve cell.

Monoclonal antibodies distinguish identifiable neurones in the leech

Monoclonal antibodies were isolated by screening 475 hybridomas obtained from mice immunized with whole leech nerve cords. The majority (about 300) reacted with leech nervous tissue, but only about 40 made antibodies that identified single kinds or small sets of cells. Twenty of the antibodies which react with specific neurones were studied in greater detail and are described here. They include antibodies against identified sensory neurones and motor neurones as well as against numerous unidentified cells.

Identification of specific leech neurones immunoreactive to enkephalin

The small endogenous peptides, Met- and Leu-enkephalin, bind to the same specific receptors as opiate analgesics. They, and the larger endorphin peptides, have been widely found in mammals, where they seem to have a significant role in neuronal pathways mediating pain and emotional behaviour. Only recently has enkephalin-like activity been identified in an invertebrate, the earthworm, although there is some preliminary evidence for opiate receptors in a marine mollusc. Here I report the detection, by an immunocytochemical technique, of an enkephalin-like moiety which is localised in one of the 400 cells of each posterior midbody ganglion of the leech. The presence of enkephalin-like activity in an identifiable easily accessible neurone of a well characterised nervous system such as that of the leech could greatly facilitate elucidation of its mechanism of action.