Longitudinal Muscle Cells Research Articles

Muscular Anatomy of the Podocoryna carnea Hydrorhiza

The muscular anatomy of the athecate hydroid Podocoryna carnea hydrorhiza is elucidated. The polyp-stolon junction is characterized by an opening, here called the chloe, in the otherwise continuous hydrorhizal perisarc. The chloe is elliptical when the polyp first arises, but takes on a more complex outline as multiple stolons anastomose to communicate with that polyp. Surrounding the polyp base are spots, here called anchors, which autofluoresce at the same wavelengths as perisarc and which, like perisarc, contain chitin as assessed by Calcofluor White, Congo Red and wheat germ agglutinin staining. Anchors remain after living tissues are digested using KOH. Collagen IV staining indicates that the mesoglea is pegged to the anchors and rhodamine phallodin staining detects cytoskeletal F-actin fibers of the basal epidermis surrounding the anchors. Longitudinal muscle fibers of the polyp broaden at the polyp base and are inserted into the mesoglea of the underlying stolon, but were neither observed to extend along the stolonal axis nor to attach to the anchors. Circular muscular fibers of the polyp extend into stolons as a dense collection of strands running along the proximal-distal axis of the stolon. These gastrodermal axial muscular fibers extend to the stolon tip. Epidermal cells at the stolon tip and the polyp bud display a regular apical latticework of F-actin staining. A similar meshwork of F-actin staining was found in the extreme basal epidermis of all stolons. Immunohistochemical staining for tubulin revealed nerves at stolon tips, but at no other hydrorhizal locations. These studies bear on the mechanisms by which the stolon tip and polyp bud pulsate, the manner in which the stolon lumen closes, and on the developmental origin of the basal epidermis of the hydrorhiza.

Peroral Endoscopic Myotomy for the Treatment of Achalasia: A Clinical Comparative Study of Endoscopic Full-Thickness and Circular Muscle Myotomy

A circular muscle myotomy preserving the longitudinal outer esophageal muscular layer is often recommended during peroral endoscopic myotomy (POEM) for achalasia. However, because the longitudinal muscle fibers of the esophagus are extremely thin and fragile, and completeness of myotomy is the basis for the excellent results of conventional surgical myotomy, this modification needs to be further debated. Here, we retrospectively analyzed our prospectively maintained POEM database to compare the outcomes of endoscopic full-thickness and circular muscle myotomy. According to the myotomy depth, 103 patients with full-thickness myotomy were assigned to group A, while 131 patients with circular muscle myotomy were assigned to group B. Symptom relief, procedure-related parameters and adverse events, manometry outcomes, and reflux complications were compared between groups. The mean operation times were significantly shorter in group A compared with group B (p = 0.02). There was no increase in any procedure-related adverse event after full-thickness myotomy (all p < 0.05). During follow-up, treatment success (Eckardt score ≤ 3) persisted for 96.0% (95 of 99) of patients in group A and for 95.0% (115 of 121) of patients in group B (p = 0.75). There were no statistically significant differences in pre- and post-treatment D-value of symptom scores and lower esophageal sphincter pressures between groups (both p > 0.05). The overall clinical reflux complication rates were also similar (21.2% vs 16.5%, p = 0.38). Short-term symptom relief and manometry outcomes of each method were comparable. Full-thickness myotomy significantly reduced the procedure time but did not increase the procedure-related adverse events or clinical reflux complications.

498 PerOral Endoscopic Myotomy for Esophageal Achalasia: a Clinical Comparative Study of Endoscopic Full-Thickness and Circular Muscle Myotomy

A circular muscle myotomy preserving the longitudinal outer esophageal muscular layer is often recommended during peroral endoscopic myotomy (POEM) for esophageal achalasia, which is different from the usual full-thickness myotomy performed surgically. Because the longitudinal muscle fibers of the esophagus are extremely thin, unintentional splitting frequently occurs during POEM. Given the fact that an incomplete myotomy with time progresses healing of myotomy edges by fibrosis may be considered as the major reason for postoperative recurrence, an intentional full-thickness myotomy may reduce the incidence of fusion by further spreading of the cut muscular wall and subsequently induce long-term symptom remission.

Brain‐derived neurotrophic factor augments the contraction of intestinal longitudinal muscle strips induced by Carbachol

BackgroundWe have demonstrated that intestinal longitudinal smooth muscle cells synthesize and secrete brain derived neurotrophic factor (BDNF) in response to neuropeptide transmitters. But the function of this BDNF in the gastrointestinal tract is undetermined.Aimto test the effect of BDNF on agonist‐induced contraction in intestinal longitudinal smooth muscle.Material and methodRabbit longitudinal muscle strips were prepared from the intestine. The contraction of the muscle strips was recorded in response to substance P 10–6M (SP 10–6) and Carbachol 10–5M (CCh 10–5). Muscle strips were preincubated with 10 nM exogenous BDNF and the changes in SP/CCh‐induced contraction were examined. A Trk antagonist and two Trk B specific agonists were used to investigate the role of the Trk B receptor in the effect of BDNF on contraction.ResultsBDNF significantly enhanced the contraction of longitudinal smooth muscle induced by CCh 10–5. However, contraction induced by SP 10–6 was not affected by pretreatment with BDNF. The pan Trk receptor inhibitor (K252a) inhibited the effect of BDNF on CCh‐induced contraction. Moreover, two Trk B agonists (LM 22A4 &amp; 7, 8‐dihydroxyflavone) augmented the CCh‐induced contraction of the longitudinal muscle strips.ConclusionBDNF enhances the cholinergic‐induced longitudinal muscle contraction through the activation of its cognate Trk B receptor.

Phosphodiesterase type 1, calcitonin gene-related peptide and vasoactive intestinal polypeptide are involved in the control of human vaginal arterial vessels

ObjectiveThe vagina makes a major contribution to the normal female sexual response cycle. An increase in vaginal blood flow is considered a key event in the mechanism of sexual arousal. Recent research has focused mainly on the cyclic GMP pathway and phosphodiesterase type 5 (PDE5, cyclic GMP specific PDE) in the control of vaginal vascular smooth muscle, whereas only little is known on the role of other key proteins and mediators of cyclic nucleotide mediated signaling in this process. The aim of the present study was to evaluate in the human vagina, by means of immunohistochemistry, the expression and distribution of phosphodiesterase type 1 (PDE1, known to hydrolize both cyclic AMP and cyclic GMP) in relation to calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and protein gene product 9.5 (PGP 9.5). Study designSections of human vagina (full wall specimens) were incubated with antibodies directed against PDE1, CGRP, VIP, PGP 9.5 and alpha-actin, followed by exposure to fluorochrome-labelled secondary antibodies. Visualization was commenced by means of laser fluorescence microscopy. ResultsMicroscopic examination revealed a dense meshwork of PGP 9.5-positive nerve fibers innervating the sections of vaginal wall. Small vessels interspersing the tissue presented dense staining for PDE1 in their smooth musculature. Blood vessels were seen surrounded by PDE1-immunoreactive longitudinal smooth muscle fibers. The vessels were also found innervated by PGP-positive varicose nerve fibers characterized by the expression of CGRP. Some fibers presented immunosignals specific for VIP. ConclusionKey mediators of the cyclic AMP and cyclic GMP pathways are co-localized in nerves seen in close proximity to vascular smooth muscle expressing PDE1. These findings suggest that both signaling cascades are involved in the control of vaginal blood flow.

Ultrastructure of Interstitial Cells in Subserosa of Human Colon

We studied the ultrastructure of interstitial cells in the subserosal/adventitial layer in human colon. An interstitial cell type with an ultrastructure intermediate between fibroblast-like cells (FLC) and interstitial cells of Cajal was identified (IC-SS). IC-SS had thin and flattened branching processes, most densely arranged close to the longitudinal muscle cells. Caveolae, bundles of intermediate filaments and membrane-associated dense bands, often with a patchy basal lamina, were characteristic. Secretory organelles (granular endoplasmic reticulum, smooth endoplasmic reticulum, Golgi, coated vesicles) were prominent. The IC-SS ultrastructure was different from that of FLC in the longitudinal layer, which had no caveolae and fewer intermediate filaments. Peg-and-socket junctions between IC-SS and between IC-SS and muscle cells were present, and IC-SS processes had close, selective appositions to muscle cells. Gap junctions were not observed. Small nerve bundles were abundant, but close contacts (<100 nm) between IC-SS or muscle cells and nerves were inconspicuous. Close appositions between IC-SS and mast cells were present; close relations to macrophages were not observed. The myoid features of IC-SS are thus more pronounced in comparison with FLC of other locations in the gastrointestinal muscle. The organization and ultrastructure may suggest a regulatory nature of IC-SS on the colonic muscle layers.

Erratum for a missing eComment 'Left ventricular rupture after mitral valve replacement: the most dreaded complication'

Erratum for a missing eComment to ‘Preservation versus non-preservation of mitral valve apparatus during mitral valve replacement: a meta-analysis of 3835 patients’ [Interact CardioVasc Thorac Surg 2012;15:1033–1039]† The publisher regrets having failed to include the following eComment related to the article by Sa et al. [1]. We express our sincere apologies to the author of this eComment. eComment. Left ventricular rupture after mitral valve replacement: the most dreaded complication Author: Ovidio A. Garcia-Villarreal Department of Cardiac Surgery, Hospital of Cardiovascular Disease No. 34, IMSS, Monterrey, Mexico. E-mail: moc.liamtoh@vgoidivo. doi:10.1093/icvts/ivs467 © The Author 2012. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. I have read with great interest the article by Sa et al [1]. This meta-analysis addresses a very important topic in surgery for mitral valve disease, that is, the preservation of subvalvular structures during mitral valve replacement (MVR) and its inherent consequences. As the authors note, after the analysis of 3835 patients (1918 for MVR with subvalvular preservation and 1917 for MVR with non-preservation) the odds ratio for early mortality (0.418, p <0.001), postoperative low cardiac output syndrome (0.299, p <0.001) and 5-year mortality (0.380, p <0.001) were in favour of MVR with subvalvular preservation. Unfortunately, this meta-analysis is not specific for anterior, posterior or bileaflet preservation. Many cardiac surgeons are reluctant to preserve the anterior mitral subvalvular complex due to the risk of left ventricular (LV) outflow tract obstruction. At the same time, there are no papers that conclusively prove the role of anterior subvalvular mitral structures in the concern discussed here. With regard to posterior subvalvular preservation, this is a common and easy procedure to perform in the real world. Particular care should be taken in rheumatic cases because of leaflet calcification and chordae thickening. But perhaps we have overlooked the relationship between the section of the posterior subvalvular apparatus and the LV rupture after MVR. This is a rare but dreaded and potentially lethal complication of mitral valve surgery, with an incidence of up to 1% and an associated mortality of up to 85% [2]. Treasure et al. [3] described type I and type II left ventricular ruptures as those located in the posterior atrioventricular groove, and the area overlying the papillary muscles, respectively. Type III cited by Miller et al. [4] is in an intermediate zone between the base of the papillary and the left atrioventricular sulcus, which is directly related to untethered loop hypothesis proposed by Cobbs et al. [5]. The supporting structures of the posterior LV wall form a loop. The outer portion is composed of longitudinal muscle fibres in the LV wall, and the inner portion consists of the papillary muscles with the chordae attached to the annulus of the posterior leaflet. Thus, the surgical division of the posterior leaflet chordae can seriously weaken the posterior LV wall. In rheumatic cases with advanced alteration of the valvular structures, such as chordae thickening and shortening, and leaflet thickening and calcification, preservation of the second and third order chordae tendinae of the posterior mitral leaflet may be enough to avoid this catastrophe. Conflict of interest: none declared

Bipennate Arrangement of Soleus Muscle in Human and its Relevance to the Force of Contraction

Soleus muscle exhibits bipennate arrangement on its centro-anterior aspect and the longitudinal parallel muscle fibers on its posterior and lateral margins. Till date soleus muscle was studied as a whole muscle with less attention given on its bipennate arrangement. As per according to standard texts, increase in cross sectional area due to bipennate arrangement in soleus muscle augments the power and force of contraction.The current study was done on 50 cadaveric lower limbs. Out of them 25 were of right side and 25 were of left side. The soleus muscle was divided into four equidistant hypothetical segments i.e- I, II, III, IV by imaginary lines drawn from the highest point of origin of muscle fibers to the lowest point of merging of muscle fibers to the tendocalcaneus. In 6% of cases the pennation was not clearly visible as it was covered anteriorly with nonseparable fascial sheath due to its adherence to subfascial muscle fibers. In 94% of cases pennation was present, out of which 6% cases showed pennation from segment I to IV, 4% cases showed pennation from segment I to III, 42% cases showed pennation from segment II to IV and 38% cases showed pennation from segments II to III, while 4% cases showed pennation only in segment III. The width, length and angle of muscle fasciculus of pennation are maximum in segment II.

Ultrastructural Changes of Smooth Muscles in Varicocele Veins

Background: Varicocele is a dilatation of the pampiniform venous plexus and internal spermatic veins. It affects about 15–20% of male population and can cause infertility.Objective: To describe the most significant ultrastructural changes of the smooth muscle cells in grade 3 varicocele veins.Methods: The authors analyzed 2- to 3-cm tracts of pampiniform venous plexus from 20 patients who underwent varicocelectomy for left varicocele. Light microscopic examination was performed with Van Gieson’s stain. Ultrastructural examination was done using scanning and transmission electron microscopy.Results: Light microscopic examination revealed irregularity and separation of medial smooth muscle cells by abundant collagen fibers in varicocele veins. On scanning electron microscopy, the medial layer of varicocele veins showed hypertrophy, irregularity, and separation of the outer longitudinal smooth muscle cells and deposition of numerous fatty globules in between muscle fibers. Transmission electron microscopy showed marked indentation and chromatin condensation of the nucleus, presence of clear vacuoles and myelin figures in the cytoplasm and plasmalemmal projections and formation of ghost bodies. Furthermore, smooth muscle cells were found to have pseudopodia-like projections around adjacent elastic and collagen fibers.Conclusions: The degenerative changes observed in smooth muscle cells and presence of abundant collagen fibers in the medial layer may contribute to the development of the varicocele of pampiniform venous plexus. Further molecular studies are required to shed more light for the underlying mechanism.

Myogenic regional responsiveness to cholinergic and vipergic stimulation in human colon

Differences in the actions of enteric neurotransmitters on colonic circular and longitudinal muscle layers have not been clearly determined, nor the possible existence of intrinsic myogenic phenotypes that might contribute to regional differences in human colon motor activity. The aim of this study was to analyze the direct pharmaco-mechanical coupling of carbachol (CCh) and vasoactive intestinal polypeptide (VIP) on human colonic smooth muscle strips and cells. Circular and longitudinal muscle strips and cells were obtained from 15 human specimens of ascending and sigmoid colon. Both isometric tension on muscle strips and contraction and relaxation on cells were measured in response to increasing CCh and VIP concentrations. Circular muscle strips of ascending colon were more sensitive to the effect of CCh than that of sigmoid colon, EC(50) values being, respectively, 4.15μmolL(-1) and 8.47μmolL(-1) (P<0.05), although there were no differences in maximal responses. No regional differences were observed in longitudinal muscle strips or in smooth muscle cells. Maximal responses to CCh were higher on circular than longitudinal muscle strips and cells throughout the colon. A greater sensitivity to VIP was observed in ascending colon compared with sigmoid colon, both in circular (EC(50:) 0.041 and 0.15μmolL(-1) , respectively, P<0.01) and longitudinal (EC(50:) 0.043 and 0.09μmolL(-1) , respectively, P<0.05) strips, and similar differences were observed in longitudinal smooth muscle cells (EC(50:) 44.85 and 75.24nmolL(-1) , respectively, P<0.05). Regional myogenic differences in pharmaco-mechanical coupling between the enteric neurotransmitters and smooth muscle contribute to the complex regional motor patterns of human colon.

Soft robotic arm inspired by the octopus: I. From biological functions to artificial requirements

Octopuses are molluscs that belong to the group Cephalopoda. They lack joints and rigid links, and as a result, their arms possess virtually limitless freedom of movement. These flexible appendages exhibit peculiar biomechanical features such as stiffness control, compliance, and high flexibility and dexterity. Studying the capabilities of the octopus arm is a complex task that presents a challenge for both biologists and roboticists, the latter of whom draw inspiration from the octopus in designing novel technologies within soft robotics. With this idea in mind, in this study, we used new, purposively developed methods of analysing the octopus arm in vivo to create new biologically inspired design concepts. Our measurements showed that the octopus arm can elongate by 70% in tandem with a 23% diameter reduction and exhibits an average pulling force of 40 N. The arm also exhibited a 20% mean shortening at a rate of 17.1 mm s−1 and a longitudinal stiffening rate as high as 2 N (mm s)−1. Using histology and ultrasounds, we investigated the functional morphology of the internal tissues, including the sinusoidal arrangement of the nerve cord and the local insertion points of the longitudinal and transverse muscle fibres. The resulting information was used to create novel design principles and specifications that can in turn be used in developing a new soft robotic arm.

726 BMP-7 SERVES AS A PROGNOSTIC BIOMARKER IN EVALUATING URETEROPELVIC JUNCTION (UPJ) OBSTRUCTIONS

(2&20 ng/ml) and/or with soluble TGFR, which blocks bioactivity. Organs were harvested after 6 days and the expression of Smooth Muscle Actin( SMA)& PCNA(proliferation) were assessed using immunohistochemistry. The muscle content of the UVJ and ureter were analyzed by flowcytometry. RESULTS: TGF& TGFR2 positive cells were immunodetected in embryonic ureters. The TGFexpression was highest on E18 and had decreased postnataly. Exogenous TGFdecreased ureterovesical(UV) muscle differentiation and proliferation. The longitudinal muscle fibers were significantly less in TGFexplants. TGFalso decreased the proportions of cells expressing SMA. SolubleTGFR blocked the effects of exogenous TGF. CONCLUSIONS: In organ-culture, exogenous TGFpostpones the UV smooth muscle proliferation and affects the muscular structure. Whether the effects of TGFare direct or indirect these form an invitro-megaureter model. The finding that TGFis highest in embryonic ureters in-vivo and decreases postnataly,suggests that a pathological persistance might potentialy explain the pathogenesis of primary megaureters.

Substance P‐induced increase in Brain Derived Neurotrophic Factor expression and secretion by intestinal smooth muscle is mediated by a rise in intracellular Ca2+

BackgroundWe have previously shown that intestinal longitudinal smooth muscle cells express and secrete brain derived neurotrophic factor (BDNF) and addition of substance P (SP) to cultured smooth muscle cells induces further expression and secretion of BDNF above basal levels. It is not known, however, what cellular signaling pathways mediate SP‐induced expression and secretion of BDNF.AimTo identify the signaling pathways involved in BDNF synthesis and secretion by smooth muscle in response to SP.MethodCultured intestinal smooth muscle cells were treated with 10–100 nM SP for 24 hours in the presence and absence of 1,2 bis (o‐aminophenoxy)ethane‐N,N,N’,N’‐tetraacetic acid (BAPTA) to chelate intracellular Ca2+. BDNF protein expression and secretion were measured by in‐cell western and ELISA, and BDNF mRNA expression was measured by qRT‐PCR.ResultsThe expression of BDNF protein was increased by 10–121% and BDNF secretion was increased by 50% by SP. Consistent with this, BDNF mRNA expression was increased by 161% by SP. Both BDNF protein and mRNA responses to SP were blocked by BAPTA.ConclusionSP stimulation of BDNF expression and secretion requires increased in intracellular Ca2+. The source of the intracellular Ca2+ increased remains to be determined. Supported by grants DK15564 and DK34153 from the National Institutes of Health.

Oligodendrorhynchus hesperides gen. et sp. n. (Heteronemertea) from the Bellingshausen Sea

Oligodendrorhynchus hesperides gen. et sp. n. (Heteronemertea) from the Bellingshausen Sea A new genus and species of heteronemertean from the Antarctic (Bellingshausen Sea), Oligodendrorhynchus hesperides, is described and illustrated. Some morphological features with major systematic significance are following: the mode of branching of the proboscis and its low number of terminal branches; the lack of horizontal lateral cephalic slits but in their place a pair of shallow epidermal depressions; a gelatinous amorphous connective stratum between the outer longitudinal and circular muscle layers; the presence of a rhynchocoelic nerve; isolated fibres of the rhynchocoel circular muscle layer interwoven with bundles of the adjacent body-wall inner longitudinal muscle fibres in the intestinal region. Other anatomical characters which can also be used to distinguish the new taxon from existing heteronemertean species that have a branched proboscis are also discussed.

Circular smooth muscle contributes to esophageal shortening during peristalsis

To study the angle between the circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) fibers in the distal esophagus. In order to identify possible mechanisms for greater shortening in the distal compared to proximal esophagus during peristalsis, the angles between the LSM and CSM layers were measured in 9 cadavers. The outer longitudinal layer of the muscularis propria was exposed after stripping the outer serosa. The inner circular layer of the muscularis propria was then revealed after dissection of the esophageal mucosa and the underlying muscularis mucosa. Photographs of each specimen were taken with half of the open esophagus folded back showing both the outer longitudinal and inner circular muscle layers. Angles were measured every one cm for 10 cm proximal to the squamocolumnar junction (SCJ) by two independent investigators. Two human esophagi were obtained from organ transplant donors and the angles between the circular and longitudinal smooth muscle layers were measured using micro-computed tomography (micro CT) and Image J software. All data are presented as mean ± SE. The CSM to LSM angle at the SCJ and 1 cm proximal to SCJ on the autopsy specimens was 69.3 ± 4.62 degrees vs 74.9 ± 3.09 degrees, P = 0.32. The CSM to LSM angle at SCJ were statistically significantly lower than at 2, 3, 4 and 5 cm proximal to the SCJ, 69.3 ± 4.62 degrees vs 82.58 ± 1.34 degrees, 84.04 ± 1.64 degrees, 84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees, P = 0.013, P = 0.008, P = 0.004, P = 0.009 respectively. The CSM to LSM angle at SCJ was also statistically significantly lower than the angles at 6, 7 and 8 cm proximal to the SCJ, 69.3 ± 4.62 degrees vs 80.18 ± 2.09 degrees, 81.81 ± 1.75 degrees and 80.96 ± 2.04 degrees, P = 0.05, P = 0.02, P = 0.03 respectively. The CSM to LSM angle at 1 cm proximal to SCJ was statistically significantly lower than at 3, 4 and 5 cm proximal to the SCJ, 74.94 ± 3.09 degrees vs 84.04 ± 1.64 degrees, 84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees, P = 0.019, P = 0.008, P = 0.02 respectively. At 10 cm above SCJ the angle was 80.06 ± 2.13 degrees which is close to being perpendicular but less than 90 degrees. The CSM to LSM angles measured on virtual dissection of the esophagus and the stomach on micro CT at the SCJ and 1 cm proximal to the SCJ were 48.39 ± 0.72 degrees and 50.81 ± 1.59 degrees. Rather than the angle of the CSM and LSM being perpendicular in the esophagus we found an acute angulation between these two muscle groups throughout the lower 10 cm of the esophagus. The oblique angulation of the CSM may contribute to the significantly greater shortening of distal esophagus when compared to the mid and proximal esophagus during peristalsis.

Analysis of pacemaker activity in the human stomach

Extracellular electrical recording and studies using animal models have helped establish important concepts of human gastric physiology. Accepted standards include electrical quiescence in the fundus, 3 cycles per minute (cpm) pacemaker activity in corpus and antrum, and a proximal-to-distal slow wave frequency gradient. We investigated slow wave pacemaker activity, contractions and distribution of interstitial cells of Cajal (ICC) in human gastric muscles. Muscles were obtained from patients undergoing gastric resection for cancer, and the anatomical locations of each specimen were mapped by the operating surgeon to 16 standardized regions of the stomach. Electrical slow waves were recorded with intracellular microelectrodes and contractions were recorded by isometric force techniques. Slow waves were routinely recorded from gastric fundus muscles. These events had similar waveforms as slow waves in more distal regions and were coupled to phasic contractions. Gastric slow wave frequency was significantly greater than 3 cpm in all regions of the stomach. Antral slow wave frequency often exceeded the highest frequency of pacemaker activity in the corpus. Chronotropic mechanisms such as muscarinic and prostaglandin receptor binding, stretch, extracelluar Ca(2+) and temperature were unable to explain the observed slow wave frequency that exceeded accepted normal levels. Muscles from all regions through the thickness of the muscularis demonstrated intrinsic pacemaker activity, and this corresponded with the widespread distribution in ICC we mapped throughout the tunica muscularis. Our findings suggest that extracellular electrical recording has underestimated human slow wave frequency and mechanisms of human gastric function may differ from standard laboratory animal models.

The ultrastructure of the ejaculatory duct in the springtail Orchesella villosa (Geoffroy) (Hexapoda, Collembola) and the formation of the spermatophore

The initial part of the ejaculatory duct of Orchesella villosa contains a “valve” and a “sorter” avoiding respectively the reflow and allowing the separation of the secretion for the spermatophore stalk from the sperm fluid. For most of its length, the ejaculatory duct lumen is divided into two parts: in the dorsal part the sperm fluid flows while in the ventral district the secretion for the stalk occurs. Laterally, on both sides of the duct, longitudinal muscle fibers are present. The epithelium of the dorsal region consists of two types of long secretory cells; the most peculiar of them are those provided with extracellular cisterns flowing directly into the duct lumen as it occurs in 1st type of epidermal cells. These cells could be involved in the control of the viscosity of the sperm fluid. The second type of cells produce a secretion probably involved in the formation of the outer coat of the apical sperm droplet. The ventral epithelium consists of short cells contributing to the enrichment of the secretion for the spermatophore stalk and perhaps also to the viscosity of the secretion flowing in the lumen. In the distal part of the ejaculatory duct, the ventral district is provided with a thick layer of muscle fibers and with 3 + 3 cuticular laminae dividing the lumen into a series of slits through which the secretion of the stalk is squeezed out into filaments. This organization allows the twisting and hardening of these filaments. A drop of sperm fluid is laid on top of the long and rigid spermatophore stalk.

Muscular effects of orexin A on the mouse duodenum: mechanical and electrophysiological studies

Orexin A (OXA) has been reported to influence gastrointestinal motility, acting at both central and peripheral neural levels. The aim of the present study was to evaluate whether OXA also exerts direct effects on the duodenal smooth muscle. The possible mechanism of action involved was investigated by employing a combined mechanical and electrophysiological approach. Duodenal segments were mounted in organ baths for isometric recording of the mechanical activity. Ionic channel activity was recorded in current- and voltage-clamp conditions by a single microelectrode inserted in a duodenal longitudinal muscle cell. In the duodenal preparations, OXA (0.3 μM) caused a TTX-insensitive transient contraction. Nifedipine (1 μM), as well as 2-aminoethyl diphenyl borate (10 μM), reduced the amplitude and shortened the duration of the response to OXA, which was abolished by Ni(2+) (50 μM) or TEA (1 mM). Electrophysiological studies in current-clamp conditions showed that OXA caused an early depolarization, which paralleled in time the contractile response, followed by a long-lasting depolarization. Such a depolarization was triggered by activation of receptor-operated Ca(2+) channels and enhanced by activation of T- and L-type Ca(2+) channels and store-operated Ca(2+) channels and by inhibition of K(+) channels. Experiments in voltage-clamp conditions demonstrated that OXA affects not only receptor-operated Ca(2+) channels, but also the maximal conductance and kinetics of activation and inactivation of Na(+), T- and L-type Ca(2+) voltage-gated channels. The results demonstrate, for the first time, that OXA exerts direct excitatory effects on the mouse duodenal smooth muscle. Finally, this work demonstrates new findings related to the expression and kinetics of the voltage-gated channel types, as well as store-operated Ca(2+) channels.

Myoanatomy and serotonergic nervous system of plumatellid and fredericellid phylactolaemata (lophotrochozoa, ectoprocta)

The phylogenetic position of the Ectoprocta within the Lophotrochozoa is discussed controversially. For gaining more insight into ectoproct relationships and comparing it with other potentially related phyla, we analysed the myoanatomy and serotonergic nervous system of adult representatives of the Phylactolaemata (Plumatella emarginata, Plumatellavaihiriae, Plumatella fungosa, Fredericella sultana). The bodywall contains a mesh of circular and longitudinal muscles. On its distal end, the orifice possesses a prominent sphincter and continues into the vestibular wall, which has longitudinal and circular musculature. The tentacle sheath carries mostly longitudinal muscle fibres in Plumatella sp., whereas F. sultana also possesses regular circular muscle fibres. Three groups of muscles are associated with the lophophore: 1) Lophophoral arm muscles (missing in Fredericella), 2) epistome musculature and 3) tentacle musculature. The epistome flap is encompassed by smooth muscle fibres. A few fibres extend medially over the ganglion to its proximal floor. Abfrontal tentacle muscles have diagonally arranged muscle fibres in their proximal region, whereas the distal region is formed by a stack of muscles that resemble an inverted 'V'. Frontal tentacle muscles show more variation and either possess one or two bases. The digestive tract possesses circular musculature which is striated except at the intestine where it is composed of smooth muscle fibres. The serotonergic nervous system is concentrated in the cerebral ganglion. From the latter a serotonergic nerve extends to each tentacle base. In Plumatella the inner row of tentacles at the lophophoral concavity lacks serotonergic nerves. Bodywall musculature is a common feature in many lophotrochozoan phyla, but among other filter feeders like the Ectoprocta is only present in the 'lophophorate' Phoronida. The longitudinal tentacle musculature is reminiscent of the condition found in phoronids and brachiopods, but differs to entoproct tentacles. Although this study shows some support for the 'Lophophorata', more comparative analyses of possibly related phyla are required.

The neuromuscular system in freshwater furcocercaria from Belarus. II Diplostomidae, Strigeidae, and Cyathocotylidae

The neuromuscular system (NMS) in cercariae of Diplostomum pseudospathaceum, Cotylurus szidati, Australapatemon burti, Holostephanus volgensis, and Paracoenogonimus ovatus was studied with immunocytochemical methods and confocal scanning laser microscopy. The patterns of F-actin in the musculature, 5-HT immunoreactive (-IR), FMRF-amide-IR neuronal elements, and α-tubulin-IR in sensory receptors were investigated. The NMS in the five species studied were compared with each other and with three species of Schistosomatidae studied earlier (Bilharziella polonica, Trichobilharzia szidati, and Trichobilharzia franki). No major structural differences in the musculature, the 5-HT-IR or FMRF-IR neuronal elements were noticed between the cercariae. The minor variations observed in the musculature were related to the size and organization of the muscle fibers. The checked pattern formed by the transverse muscle fibers in the tail stems of D. pseudospathaceum, C. szidati, A. burti, H. volgensis, and P. ovatus was not observed in B. polonica, T. szidati, and T. franki. A trend in the differentiation of the longitudinal muscle fibers in the furca from evenly distributed fibers in H. volgensis and P. ovatus to many bundles in D. pseudospathaceum and two well-organized lateral bundles in C. szidati, A. burti, and Trichobilharzia spp. was observed. The transverse muscle fibers in the furca follow the same trend. The number of 5-HT-IR neurons in the cercarial bodies varied between 10 and 16. In cercariae of H. volgensis and P. ovatus, the central nervous system (CNS) was less centralized compared to the CNS in the other species studied, with only two 5-HT-IR marker neurons in each brain ganglion and the other neurons distributed evenly along the main cords. In the tails of H. volgensis and P. ovatus, many transverse 5-HT-IR comissures were found. In the tails of higher strigeidid cercariae, only a few crosslinks were observed. The number and distribution of sensory receptors on the bodies and tails of the cercarial species differed from each other. A trend in the differentiation of the sensory receptors in the tails was discerned. A process of grouping and decrease in number of ciliated receptors in the stem and in the furca from H. volgensis and P. ovatus to Schistosomatid cercariae took place.