大鼠食管胸段，腹段乙酰胆碱酯酶阳性神经的配布

大鼠食管胸段和腹段壁内乙酰胆碱酯酶（ＡＣｈＥ）阳性神经存在于神经束和分支的粗细神经纤维内,也见于外膜丛,肌间丛,粘膜下丛和粘膜肌内。食管肌层内ＡＣｈＥ阳性神经纤维多而密集,而食管腹段肌内尤为丰富,肌间神经纤维末梢分布于肌束表面,可能与控制肌纤维活动有关;分布于肌内,粘膜下层和上皮基部的ＡＣｈＥ阳性神经中,尚含有内脏感觉神经纤维。食管壁的肌间丛和粘膜下丛内散在有多极形和卵园形的ＡＣｈＥ阳性神经元,在食管腹段内数多,而以中小型神经元为主。     

Early innervation of skeletal muscle during tail regeneration in urodele amphibians.

The innervation pattern of skeletal muscles was studied in the normal and regenerating tail of Notophthalmus viridescens. Silver staining for nerve endings and histochemical localization of acetylcholinesterase (AChE) were used for light microscopy. In In normal musculature, AChE positive reactions were localized at the ends of the muscle fibers where they are anchored on connective tissue septa by myotendinous junctions. At this level, silver staining shows nerve terminals forming endplates. During regeneration, positive reactions for AChE appear de novo as dense plates localized at the ends of the newly formed myotubes. The mechanisms involved in the localization of AChE on this surface seem to operate before previous local contacts by nerve terminals. From the ultrastructural data and immunohistochemical results with anti-laminin antibody, these observations suggest that regenerating muscle fibers determine a region of post-synaptic specialization in close relation with the organization of myotendinous regions and basement membrane formation. Nerve-muscle contacts appear at these levels at stage IV (15-20 days after amputation) in the stump and in the rostral part of the regenerate (transition zone). These nerve terminals are provided by the disorganized peripheral nervous system of the injured segment. In the regenerate a similar pattern of AChE reaction can be seen in every myotube, differentiating according to a rostro-caudal gradient. Innervation at the ends of the muscle fibers is in spatiotemporal relation with the exists of the ventral roots from the regenerating nerve cord as the regenerate continues to grow in length.     

Histological study of motor innervation to long nuclear chain intrafusal fibers in the muscle spindle of the cat

Several muscle spindles of the cat tenuissimus muscle were cut in serial, 1-micron thick transverse sections and stained with toluidine blue in search for long nuclear chain intrafusal muscle fibers. Five complete poles of the long chain fibers were located. Each fiber pole displayed one plate-type motor ending situated in the extracapsular fiber region. The endings were supplied by myelinated motor axons that originated from intramuscular nerve fascicles containing motor axons to extrafusal muscle fibers. One of the endings was innervated by a collateral from a motor axon that supplied an extrafusal end-plate. Ultrastructurally, the long chain endings resembled extrafusal end-plates. They were more complex, in terms of prominence of sole-plate and degree of post-junctional folding, than any other intrafusal ending present in the spindles. The motor endings of the long chain fibers were assumed to be the terminals of static (fast) skeletofusimotor axons, which preferentially innervate the longest nuclear chain fibers of cat muscle spindles.     

On the issue of innervation of dorsal longitudinal musculature of <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> with inferior cervical nerve

Using the method of the anterograde dextran tetramethylrhodamin transport, there is obtained the topographic picture of branching of inferior cervical nerve axons on fibers of the dorsal longitudinal muscle in Lymnaea stagnalis (L.). Using the retrograde staining, the neuronal bodies sending their processes into this nerve are marked. Manifestations of asymmetry in distribution of neurons stained through the right and left nerves are described. The electron microscopic studies have shown that the main number of the inferior cervical nerve axons is represented by thin fibers presumably belonging to the sensory cells. A part of the nerve fibers and their endings show imunoreactivity to serotonin and acetylcholine. The serotoninergic fibers predominate quantitatively over the cholinergic ones and account for a half of the fibers stained with dextran. A possible functional role of the serotoninergic and cholinergic innervation of the dorsal longitudinal muscle in Lymnaea stagnalis is discussed.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 40, No. 6, 2004, pp. 569–578.     

Morphological study of nerve endings in jaw muscles of post-hatching American alligators (Alligator mississippiensis)

Two months after hatching, the fibers of the jaw muscles of the American alligator are associated with three types of nerve terminals namely, plates, simple plates, and grape endings. Simple plate endings are mainly observed on the small muscle fibers. Grape-type endings are found on muscle fibers that resemble the tonic fibers of garter snakes (Hess, Am. J. Anat., '63). Most terminals are plate endings and account for 53.7–74.7% of terminals per muscle. Fibers with grape-type endings were found in all the jaw muscles studied; they lack well organized T-systems, M-lines, and post-junctional sarcolemmal folds, as well as irregularly distributed small of fibrils, and zigzag Z-lines. The properties of nerve endings of the American alligator indicate that M. depressor mandibulae, M. pseudotemporalis, and M. pterygoideus posterior have primary roles in jaw movements. M. pterygoideus anterior and M. intramandibularis contribute mainly to postural adjustments of the jaws. The multiplicity of nerve terminals in the jaw muscles of American alligators contrasts with the simple movements of their jaws. © 1994 Wiley-Liss, Inc.     

Innervation of regenerated spindles in muscle grafts of the rat

Features of the nerve supply and the encapsulated fibers of muscle spindles were assessed in grafted and normal extensor digitorum longus (EDL) muscles of rats by analysis of serial 10-microns frozen transverse sections stained for enzymes which delineated motor and sensory endings, oxidative capacity and muscle fiber type. The number of fibers was significantly more variable, and branched fibers were more frequently observed in regenerated spindles than in control spindles. Forty-eight percent of regenerated spindles received sensory innervation. Spindles reinnervated by afferents had a larger periaxial space than did spindles which were not reinnervated by afferents. Regenerated fibers innervated by afferents had small cross-sectional areas, equatorial regions with myofibrils restricted to the periphery of fibers, unpredictable patterns of nonuniform and nonreversible staining along the length of the fiber for 'myofibrillar' adenosine triphosphatase (mATPase) after acid and alkaline preincubation. In contrast, regenerated fibers devoid of sensory innervation resembled extrafusal fibers in that they usually exhibited myofibrils throughout the length of the fiber, no central aggregations of myonuclei, uniform staining for mATPase and a reversal of staining for mATPase after preincubation in an acid or alkaline medium. Approximately thirty percent of encapsulated fibers devoid of sensory innervation stained analogous to a type I extrafusal fiber, a pattern of staining never observed in intrafusal fibers of normal spindles. Groups of encapsulated fibers all exhibiting this pattern of staining reflect that either these fibers may have been innervated by collaterals of skeletomotor axons that originally innervated type I extrafusal fibers or that fibers innervated by only fusimotor neurons express patterns of staining for mATPase similar to extrafusal fibers in the absence of sensory innervation. Sensory innervation may also influence the reestablishment of multiple sites of motor endings on regenerated intrafusal fibers. Those regenerated fibers innervated by afferents had more motor endings than did regenerated fibers devoid of sensory innervation. Differences in size, morphology, and patterns of staining for mATPase and numbers of motor endings between fibers innervated by afferents and fibers devoid of sensory innervation reflect that afferents can influence the differentiation of muscle cells and the reestablishment of motor innervation other than during the late prenatal/early postnatal period when muscle spindles form and differentiate in rats.     

Identification of sensory neurons supplying receptors in lingual muscles of the rat: histochemical and retrograde labeling study with horseradish peroxidase.

Sensory innervation of lingual musculature was studied in young adult Wistar rats using retrograde labeling by horseradish peroxidase (HRP) and combined silver impregnation and acetylcholinesterase (AchE) methods. Intra-lingual injection of HRP resulted in labeling of neuronal somata in the trigeminal, superior vagal, and second cervical spinal (C2) ganglia. When HRP was directly applied to the proximal stump of severed hypoglossal nerve, labeling occurred only in the cervical and superior vagal ganglia. Morphometric analysis revealed that the labeled neurons were of the small-sized category in all ganglia. However, in the trigeminal and C2 ganglia, labeling occurred also among the medium-sized neurons. Combined silver and AchE preparations from lingual muscles revealed the absence of typical muscle spindles. Instead, there were free and spiral nerve terminals in the interstitium, and epilemmal knob-like or bouton-like endings surrounding non-encapsulated muscle fibers. These terminals showed AchE -ve reaction in contrast to the motor ones. Few ganglionic cells were scattered along the hypoglossal nerve with uniform AchE +ve reaction in their perikarya. This indicates that medium-sized neurons in the trigeminal and C2 ganglia, and probably sensory neurons along the hypoglossal nerve mediate lingual muscle sensibility perceived by atypical sensory terminals.     

Morphological studies of fiber types of striated muscle fibers of the cremaster in the guinea pig

THe fine structure of the striated muscle fibers of the cremaster of the guinea pig was studied using the cholinesterase technique and light and electron microscopy. Under light microscopy, isolated single muscle fibers showed two types of nerve endings: the first one presented elliptic or oval areas having digit-like structures inside, some of the borders of which were heavily stained. These fibers had only one end-plate. The second type presented elongated clear areas with most of the density located on the borders. Several nerve endings were apparent in these fibers. By electron microscopy, the former had large and numerous sarcolemmal foldings and these characteristics were also observed in unstained fibers. In the latter, the foldings were scanty or absent. At the ultrastructural level, the fibers having only one end-plate presented a regular array of fibrils with an abundant sarcoplasmic reticulum ('Fibrillenstruktur' type) in contrast to the multi-innervated fiber with an irregular distribution pattern of fibrils and a scarce sarcoplasmic reticulum ('Felderstruktur' type). The striated muscle fiber layer of the cremaster probably contains both fast and slow fibers. The possible functional role for the slow striated muscle fibers is discussed.     

Acetylcholinesterase from the motor nerve terminal accumulates on the synaptic basal lamina of the myofiber

Acetylcholinesterase (AChE) in skeletal muscle is concentrated at neuromuscular junctions, where it is found in the synaptic cleft between muscle and nerve, associated with the synaptic portion of the myofiber basal lamina. This raises the question of whether the synaptic enzyme is produced by muscle, nerve, or both. Studies on denervated and regenerating muscles have shown that myofibers can produce synaptic AChE, and that the motor nerve may play an indirect role, inducing myofibers to produce synaptic AChE. The aim of this study was to determine whether some of the AChE which is known to be made and transported by the motor nerve contributes directly to AChE in the synaptic cleft. Frog muscles were surgically damaged in a way that caused degeneration and permanent removal of all myofibers from their basal lamina sheaths. Concomitantly, AChE activity was irreversibly blocked. Motor axons remained intact, and their terminals persisted at almost all the synaptic sites on the basal lamina in the absence of myofibers. 1 mo after the operation, the innervated sheaths were stained for AChE activity. Despite the absence of myofibers, new AChE appeared in an arborized pattern, characteristic of neuromuscular junctions, and its reaction product was concentrated adjacent to the nerve terminals, obscuring synaptic basal lamina. AChE activity did not appear in the absence of nerve terminals. We concluded therefore, that the newly formed AChE at the synaptic sites had been produced by the persisting axon terminals, indicating that the motor nerve is capable of producing some of the synaptic AChE at neuromuscular junctions. The newly formed AChE remained adherent to basal lamina sheaths after degeneration of the terminals, and was solubilized by collagenase, indicating that the AChE provided by nerve had become incorporated into the basal lamina as at normal neuromuscular junctions.     

An electron microscopic study on the innervation of the gill filaments of a lamprey,Lampetra japonica

This paper reports observations on the innervation of gill filaments of the lamprey, Lampetra japonica. Nerve fibers run on each side of the afferent filament artery (AFA nerve) and in the connective tissue compartment along the efferent filament artery (EFA nerve). The AFA nerve supplies vasomotor fibers to the afferent filament artery and arteriovenous anastomoses and special visceral motor fibers to branchial muscle fibers (musculus compressor branchialis circularis). Nerve endings of the vasomotor fibers contain large, cored vesicles (60–180 nm in diameter) with a variable number of small, clear vesicles (30–70 μm in diameter), whereas those of the visceral motor fibers have many small, clear vesicles with few large, cored vesicles. The EFA nerve supplies vasomotor fibers to the efferent filament artery. Their endings, containing mixtures of predominantly large, cored vesicles and small, clear vesicles make close synaptic contacts with reticular cells. The latter in turn are connected with each other or with smooth muscle cells in the wall of the efferent filament artery by nexuses. No nerves are found in the axial plate between the afferent and efferent filament arteries nor in the secondary lamellae of individual gill filaments. No afferent nerve supply to the gill filament has been found.     

Sympathetic and sensory innervation of small intensely fluorescent (SIF) cells in rat superior cervical ganglion

The sympathetic ganglion contains small intensely fluorescent (SIF) cells derived from the neural crest. We morphologically characterize SIF cells and focus on their relationship with ganglionic cells, preganglionic nerve fibers and sensory nerve endings. SIF cells stained intensely for tyrosine hydroxylase (TH), with a few cells also being immunoreactive for dopamine β-hydroxylase (DBH). Vesicular acetylcholine transporter (VAChT)-immunoreactive puncta were distributed around some clusters of SIF cells, whereas some SIF cells closely abutted DBH-immunoreactive ganglionic cells. SIF cells contained bassoon-immunoreactive products beneath the cell membrane at the attachments and on opposite sites to the ganglionic cells. Ganglion neurons and SIF cells were immunoreactive to dopamine D2 receptors. Immunohistochemistry for P2X3 revealed ramified nerve endings with P2X3 immunoreactivity around SIF cells. Triple-labeling for P2X3, TH and VAChT allowed the classification of SIF cells into three types based on their innervation: (1) with only VAChT-immunoreactive puncta, (2) with only P2X3-immunoreactive nerve endings, (3) with both P2X3-immunoreactive nerve endings and VAChT-immunoreactive puncta. The results of retrograde tracing with fast blue dye indicated that most of these nerve endings originated from the petrosal ganglion. Thus, SIF cells in the superior cervical ganglion are innervated by preganglionic fibers and glossopharyngeal sensory nerve endings and can be classified into three types. SIF cells might modulate sympathetic activity in the superior cervical ganglion.     

Acetylcholinesterase activity in nerve endings of tails of Rana japonica and R. catesbeiana during metamorphosis

Summary In anuran tadpole tails, the myelinated motor nerve fibers branch in the myoseptum to innervate both red and white muscle fibers at, or near, their ends. There are no significant ultrastructural differences between the nerve endings of the two types of muscle fibers.Intense acetylcholinesterase reaction product was observed in synaptic clefts and junctional folds, as well as in transverse tubules. As metamorphosis proceeded, the junctional folds of the nerve endings disappeared, however, acetylcholinesterase reaction product was still observed in the synaptic clefts. As muscle fibers began to degenerate, nerve endings began to separate from them. However, after nerve endings were completely separated from the surfaces, degenerated muscle fibers, synaptic and cored vesicles were still well preserved although no acetylcholinesterase reaction product was found. It seems clear that the mechanism of the muscle degeneration in the tadpole tail during metamorphosis is not the result of the degeneration of its nerve endings.     

Labeling afferent nerves in the tongue by peripheral transganglionic transport of HRP and WGA-HRP in the rat

Peripheral transganglionic transport of horseradish pcroxidase(HRP) and wheat germ agglutinin–horseradish peroxidaseconjugate (WGA–HRP) was used to label afferent fibersin the taste buds and lingual epithelium of the rat. Microinjectionsof the tracer were made in the brain stem central projectionarea of the afferent nerves to the tongue. Optimal labelingof nerve endings in the tongue was obtained when 2 µlof 20% HRP was injected into the brain stem and postinjectionsurvival times of 24–36 h were used. The distributionof single nerves was studied by using this tracing procedurein combination with strategic transections of the various afferentnerves supplying the tongue. Labeled nerve fibers from the combinedchorda tympani–lingual nerve were found in the epitheliumand in taste buds in the fungiform and anterior foliate papillaeof the anterior 3/4 of the tongue. Labeled nerve fibers in theepithelium of the anterior 2/3 of the tongue but none in tastebuds were found when the lingual nerve alone was studied, althoughnumerous perigeminal fibers were found. The glossopharyngealnerve was found to innervate die posterior 1/4 of the tongueepithelium including the taste buds of the circumvallate papillae.The glossopharyngeal nerve on one side was found to innervatethe taste buds on both sides of the midline. The results showthat this tracing procedure can be a useful supplement to othermethods for studying afferent nerves in the tongue.     

Functional topography and ultrastructure of periarticular mechanoreceptors in the lateral elbow region of the rat

The distribution and ultrastructure of sensory nerve endings were investigated in the deep lateral elbow region of the rat. Three zones of distribution of mechanoreceptors were distinguished, each in relation to the functional architecture of the connective and muscular tissue in that area: (1) a zone with muscle spindles, Golgi tendon organs, free nerve endings and single small lamellated corpuscles ('muscle-tendon spectrum'), situated in the middle third of the supinator muscle and its superficial aponeurosis; (2) a zone with small lamellated corpuscles and free nerve endings, situated pericapsularly to the humeroradial joint capsule ('shearing spectrum'): this moderately dense, irregular connective tissue is covered by the proximal continuation of the supinator's aponeurosis, and muscle fibers insert from beneath this aponeurosis, which displays, as a part of the joint capsule, a strong collagenous tissue plate; (3) a zone with only free nerve endings within the tendon-like, most proximal part of the supinator's aponeurosis, inserting into the periosteal layer of the lateral humeral epicondyle ('endotenonial spectrum'): it is part of the joint capsule. The ultrastructure of these sensory endings is described and the distribution pattern of the mechanoreceptors observed is discussed in relation to the classification into 'muscle receptors' and 'joint receptors'.     

Distribution of cholinergic and catecholaminergic nerves in the colon of the rat with aganglionosis.

We compared localization and distribution of putative cholinergic fibers by acetylcholinesterase and of adrenergic fibers visualized by the glyoxylic acid technique in the aganglionic segment using whole mount preparations of aganglionosis rat (AGR) and compared them with those of normal littermates. We also attempted simultaneous staining of acetylcholinesterase (AChE) and catecholamine fluorescence (C-F) on the same whole mount preparations to compare the differences in distribution pattern. All AGR used in this study had narrowed segments of the bowel extending from the distal ileum to the anus, and had no ganglion cells in these narrowed segments. In the intermuscular space, normally occupied with myenteric ganglion, of the narrowed distal colon and rectum, various sizes of nerve bundles and fibers reactive for AChE and C-F appeared to make coarse and irregular networks. These thick nerve bundles appeared to ascend to the proximal colon and disappeared in the cecum. In the distal ileum, almost totally absence of AChE positive nerve fibers, but a few fine C-F fibers, probably associated with blood vessels, were observed. By the method of simultaneous staining of AChE and C-F method in the whole mount preparations, the thick nerve bundles in the narrowed segments showed both of AChE positive and C-F positive. However, there were differences in peripheral fine nerve fibers in the segment; especially numerous perivascular C-F positive nerve fibers, but a few AChE positive ones were found. In the upper aganglionic narrowed segments, greatly diminished numbers of AChE positive and C-F positive nerve fibers were found in the circular muscle layer and in the submucosal layer. In the lower aganglionic narrowed segments, there were thick nerve bundles, forming irregular interlaced network. The role of these extrinsic nerve fibers in aganglionic segments is unclear.     

Appearance of sensory nerve terminals in cat muscle spindles stained for NADH-tetrazolium reductase

Cat muscle spindles were studied histochemically in serial transverse sections of the tenuissimus muscle stained for myofibrillar ATPase, cholinesterase or NADH-tetrazolium reductase. The terminal sites of the primary and secondary axons on intrafusal muscle fibers could be demonstrated due to their high NADH-TR activity. This sensory NADH-TR reactivity at the equator and in the juxtaequatorial regions disappeared following spindle chronic de-afferentation, but not after de-efferentation. Spindle poles that carried both primary and secondary sensory endings had a longer periaxial fluid space than poles with primary endings only, and their motor innervation, as determined by staining for ChE, was positioned at the greater distance from the equator. Some of the secondary endings occurred in intrafusal regions that displayed surface fiber ChE activity. The histochemical reaction for NADH-TR represents a simple, rapid and reliable method for studies of the distribution of sensory nerve terminals in the spindle.     

Fine structure and innervation of the avian adrenal gland

Summary Apart from cholinergic nerve fibers, which make up the main part of efferent fibers to the avian adrenal gland (Unsicker, 1973b), adrenergic, purinergic and afferent nerve fibers occur. Adrenergic nerve fibers are much more rare than cholinergic fibers. With the Falck-Hillarp fluorescence method they can be demonstrated in the capsule of the gland, in the pericapsular tissue and near blood vessels. By their green fluorescent varicosities they may be distinguished characteristically from undulating yellow fluorescent ramifications of small nerve cells which are found in the ganglia of the adrenal gland and below the capsule. The varicosities of adrenergic axons exhibit small (450 to 700 Å in diameter) and large (900 to 1300 Å in diameter) granular vesicles with a dense core which is usually situated excentrically. After the application of 6-hydroxydopamine degenerative changes appear in the varicosities. Adrenergic axons are not confined to blood vessels but can be found as well in close proximity of chromaffin cells. Probably adrenergic fibers are the axons of large ganglion cells which are situated mainly within the ganglia of the adrenal gland and in the periphery of the organ and whose dendritic endings show small granular vesicles after treatment with 6-OHDA.A third type of nerve fiber is characterized by varicosities containing dense-cored vesicles with a thin light halo, the mean diameter (1250 Å) of which exceeds that of the morphologically similar granular vesicles in cholinergic synapses. Those fibers resemble neurosecretory and purinergic axons and are therefore called p-type fibers. They cannot be stained with chromalum-hematoxyline-phloxine. Axon dilations showing aggregates of mitochondria, myelin bodies and dense-cored vesicles of different shape and diameter are considered to be afferent nerve endings. Blood vessels in the capsule of the gland are innervated by both cholinergic and adrenergic fibers.Supported by a grant from the Deutsche Forschungsgemeinschaft (Un 34/1).     

Appearance of sensory nerve terminals in cat muscle spindles stained for NADH-tetrazolium reductase

Summary Cat muscle spindles were studied histochemically in serial transverse sections of the tenuissimus muscle stained for myofibrillar ATPase, cholinesterase or NADH-tetrazolium reductase. The terminal sites of the primary and secondary sensory axons on intrafusal muscle fibers could be demonstrated due to their high NADH-TR activity. This sensory NADH-TR reactivity at the equator and in the juxtaequatorial regions disappeared following spindle chronic de-afferentation, but not after de-efferentation. Spindle poles that carried both primary and secondary sensory endings had a longer periaxial fluid space than poles with primary endings only, and their motor innervation, as determined by staining for ChE, was positioned at a greater distance from the equator. Some of the secondary endings occurred in intrafusal regions that displayed surface fiber ChE activity. The histochemical reaction for NADH-TR represents a simple, rapid and reliable method for studies of the distribution of sensory nerve terminals in the spindle.     

Innervation of regenerated spindles in muscle grafts of the rat

Summary Features of the nerve supply and the encapsulated fibers of muscle spindles were assessed in grafted and normal extensor digitorum longus (EDL) muscles of rats by analysis of serial 10-m frozen transverse sections stained for enzymes which delineated motor and sensory endings, oxidative capacity and muscle fiber type.The number of fibers was significantly more variable, and branched fibers were more frequently observed in regenerated spindles than in control spindles. Forty-eight percent of regenerated spindles received sensory innervation. Spindles reinnervated by afferents had a larger periaxial space than did spindles which were not reinnervated by afferents. Regenerated fibers innervated by afferents had small cross-sectional areas, equatorial regions with myofi-brils restricted to the periphery of fibers, unpredictable patterns of nonuniform and nonreversible staining along the length of the fiber for myofibrillar adenosine triphosphatase (mATPase) after acid and alkaline preincubation. In contrast, regenerated fibers devoid of sensory innervation resembled extrafusal fibers in that they usually exhibited myofibrils throughout the length of the fiber, no central aggregations of myonuclei, uniform staining for mATPase and a reversal of staining for mATPase after preincubation in an acid or alkaline medium. Approximately thirty percent of encapsulated fibers devoid of sensory innervation stained analogous to a type I extrafusal fiber, a pattern of staining never observed in intrafusal fibers of normal spindles. Groups of encapsulated fibers all exhibiting this pattern of staining reflect that either these fibers may have been innervated by collaterals of skeletomotor axons that originally innervated type I extrafusal fibers or that fibers innervated by only fusimotor neurons express patterns of staining for mATPase similar to extrafusal fibers in the absence of sensory innervation. Sensory innervation may also influence the reestablishment, of multiple sites of motor endings on regenerated intrafusal fibers. Those regenerated fibers innervated by afferents had more motor endings than did regenerated fibers devoid of sensory innervation.Differences in size, morphology, and patterns of staining for mATPase and numbers of motor endings between fibers innervated by afferents and fibers devoid of sensory innervation reflect that afferents can influence the differentiation of muscle cells and the reestablishment of motor innervation other than during the late prenatal/early postnatal period when muscle spindles form and differentiate in rats.     

Cross-Homologies and Structural Differences Between Human Cholinesterases Revealed by Antibodies Against cDNA-Produced Human Butyrylcholinesterase Peptides

To study the polymorphism of human cholinesterases (ChEs) at the levels of primary sequence and three-dimensional structure, a fragment of human butyrylcholinesterase (BuChE) cDNA was subcloned into the pEX bacterial expression vector and its polypeptide product analyzed. Immunoblot analysis revealed that the clone-produced BuChE peptides interact specifically with antibodies against human and Torpedo acetylcholinesterase (AChE). Rabbit polyclonal antibodies prepared against the purified clone-produced BuChE polypeptides interacted in immunoblots with denatured serum BuChE as well as with purified and denatured erythrocyte AChE. In contrast, native BuChE tetramers from human serum, but not AChE dimers from erythrocytes, interacted with these antibodies in solution to produce antibody-enzyme complexes that could be precipitated by second antibodies and that sedimented faster than the native enzyme in sucrose gradient centrifugation. Furthermore, both AChE and BuChE dimers from muscle extracts, but not BuChE tetramers from muscle, interacted with these antibodies. To reveal further whether the anti-cloned BuChE antibodies would interact in situ with ChEs in the neuromuscular junction, bundles of muscle fibers were microscopically dissected from the region in fetal human diaphragm that is innervated by the phrenic nerve. Muscle fibers incubated with the antibodies and with 125I-Protein A were subjected to emulsion autoradiography, followed by cytochemical ChE staining. The anti-cloned BuChE antibodies, as well as anti-Torpedo AChE antibodies, created patches of silver grains in the muscle endplate region stained for ChE, under conditions where control sera did not. These findings demonstrate that the various forms of human AChE and BuChE in blood and in neuromuscular junctions share sequence homologies, but also display structural differences between distinct molecular forms within particular tissues, as well as between similarly sedimenting molecular forms from different tissues.