Pressure profile along the oesophagus during eructation in sheep.

The pressure profile along the oesophagus was recorded simultaneously with the flow rate of eructated gas in sheep to evaluate the oesophageal motor events leading to the relief of gas. All the eructation sequences started by a rise followed by a plateau of oesophageal pressure. The passage of gas at the tracheal level occurred during this plateau and not during the consecutive transient lowering of the oesophageal pressure. All eructation sequences ended by a peristaltic contraction of the oesophagus. The flow rate pattern of gas during eructation was affected by head position leading to different tensions of the oesophagus. We conclude that, despite the large volume of eructated gases, the eructation process is not significantly different in sheep compared to other animals. Therefore, by virtue of its unique physiological particularity, the sheep might be used as an experimental model for the evaluation of lower oesophageal sphincter (LOS) competence.     

Protective effects of Helicobacter pylori against gastroesophageal reflux disease may be due to a neuroimmunological anti-inflammatory mechanism

There is some evidence that Helicobacter pylori infection has a protective effect against gastroesophageal reflux disease (GORD) and its complications such as Barrett's oesophagus and oesophageal adenocarcinoma. In this paper, we propose that a neuroimmunological mechanism is responsible for the protective effect of H. pylori on GORD. H. pylori infection of the gastric mucosa induces a T helper1-like immune response and production of pro-inflammatory cytokines. These cytokines can inhibit local sympathetic tone, whereas they increase systemic sympathetic tone. Increased sympathetic tone can induce an anti-inflammatory milieu, which in turn can inhibit inflammation in the oesophagus and lower oesophageal sphincter (LOS). Furthermore, H. pylori infection may stimulate the cholinergic anti-inflammatory pathway. It has been suggested that reflux-induced oesophageal inflammation plays an important role in the pathogenesis of reflux oesophagitis. Reduction of oesophageal inflammation by increased systemic sympathetic tone and vagal activity may lead to a decrease in reflux-induced oesophageal injury and LOS dysfunction in GORD.     

Evidence for a lower oesophageal sphincter in the guinea-pig

1. In vitro balloon pull-through experiments have been used to identify the guinea-pig lower oesophageal sphincter (LOS). 2. Histologically, the LOS forms a 1-2 mm ring of smooth muscle at the distal termination of the oesophagus, immediately adjacent to the gastric sling muscle. 3. Tetrodotoxin (10(-6) M) sensitive, guanethidine (10(-6) M) insensitive "on" relaxation of circular LOS muscle strips was evoked by electrical field stimulation (ES). 4. ES evoked atropine (10(-6) M) sensitive "on" contractions of gastric sling and fundus smooth muscle strips. 5. Following cessation of ES a partially atropine-sensitive "off" contraction was observed in all the smooth muscle strips. 6. The predominant response of the LOS to ES was relaxation.     

Nitric oxide synthase-containing, peptide-containing, and acetylcholinesterase-positive nerves in the cat lower oesophagus

Summary The innervation of the cat lower oesophagus, including the lower oesophageal sphincter, was studied by enzyme histochemistry, immunohistochemistry, and confocal microscopy. In the lower oesophageal sphincter, and at a level 2 cm above it, no apparent differences were seen in the nerve distribution pattern. Among the nerve populations studied, acetylcholinesterase (AChE)-positive nerves were the most abundant in both these regions. The density of AChE-positive nerves was particularly marked in the circular muscle layer. A rich supply of nitric oxide synthase (NOS)-containing nerves was identified by using an antiserum against neuronal NOS, or by enzyme histochemical staining for NADPH diaphorase activity. Vasoactive intestinal peptide (VIP)-immunoreactive nerves had a similar distribution pattern as NOS-immunoreactive nerves, and nerves displaying immunoreactivity for NOS and VIP often showed profiles coinciding with AChE-positive nerves. As judged by confocal microscopy, immunoreactivities for helospectin, pituitary adenylate cyclase-activating peptide (PACAP) and VIP, to a large extent were found in the same nerves. At a level 7 cm above the lower oesophageal sphincter, the total nerve supply was less than in the sphincter itself and 2 cm above it. Immunoreactivity towards VIP, PACAP and helospectin was also found to co-exist with NOS and neuropeptide Y within the same nerve structures. It is concluded that there is an intricate innervation pattern in the feline lower oesophagus reflecting the complexity in the regulation of its motility.     

Biomechanical properties of oesophagus wall under loading

In this investigation, firstly, the biomechanical properties of different parts of oesophagus were determined. Oesophagus stress and strain are the greatest in the cervical part for all age groups. The human oesophagus deforms unevenly, depending on the direction of load in relation to the organ's axis, it exhibits anisotropical behaviour. With the age the values of mechanical parameters of the oesophagus wall reduce, in particular beginning from 45 years of age, but the modulus of elasticity increases. Biomechanical properties of the oesophagus depend on the architecture of its structure. By loading the organ in the circumferential direction, microfibrilae rupture and deformation of the muscular fibres occurs. With increase of load, collagenous fibres straighten and microruptures in collagenous fibrilae occur. With stretching of oesophagus longitudinally, collagenous fibres partially preserve their wavy and helical configuration. Therefore, higher resistance of the oesophageal wall occurs in the longitudinal direction.     

Origin of the secondary peristalsis of the esophagus in sheep

Manometric and electromyographic methods were used for investigating oesophageal motor activity in conscious sheep. A contraction wave, the so-called "secondary peristalsis", was readily evoked by means of the fast inflation of a rubber balloon distending the oesophagus. This peristaltic wave travels onto the cardia at the same speed as the primary deglutitive peristalsis (28 m X sec-1, approximately). In that particular species, whose oesophageal muscular coat is all along entirely made of striated fibers, secondary peristalsis is always initiated at the origin of the cervical oesophagus, whatever the site, cervical or thoracic, of the distension.     

Effects of regulatory peptides on the porcine lower oesophageal sphincter

Studies were performed to investigate the effects of neurotransmitters and neurotransmitter candidates (substance P, VIP, somatostatin, Met-enkephalin, gastrin-17, CCK-4 and -8, neurotensin and TRH) of the newly discovered peptidergic nervous system on lower oesophageal sphincter pressure in anaesthetized pigs. All neuropeptides were infused over 2 min periods in 6 different doses, separated by resting periods of at least 1 min, directly into the arterial supply of the lower oesophageal sphincter. Substance P caused a dose-dependent increase in lower oesophageal shpincter pressure; the threshold dose was 9 pmol . kg-1 . min-1 and half maximal response occurred at 72 pmol . kg-1 . min-1. None of the other polypeptides, however, influenced the resting lower oesophageal sphincter. These studies show that substance P is a potent stimulant of smooth muscle in the lower oesophageal sphincter, suggesting that this peptide may be an important regulator of lower oesophageal sphincter pressure.     

The elastic fibre system in the veins of the human lower oesophagus

The elastic, elaunin and oxytalan fibres in the tunica mucosa and tela submucosa of veins of the human lower oesophagus were studied in 30 necropsy and biopsy specimens using appropriate histological and ultrastructural methodologies. Elaunin fibres predominate in the veins endowed with muscle cells. Scattered oxytalan and elastic fibres were also observed, the latter being more numerous at the vein periphery. No noteworthy fibre arrangement was encountered in veins lacking muscle cells. Those fibres disposed around the veins were considered to belong to the connective tissue of the tunica mucosa and tela submucosa in which they are embedded. The veins of the lower oesophagus seem to be of low elasticity, which may be related to a blockage mechanism described for the gastro-oesophageal blood stream in cases of portal hypertension.     

Functional anatomy of the human saccus lacrimalis

The relations between the saccus lacrimalis and different portions of the musculus orbicularis oculi were studied in orbital regions of human fetuses sectioned into numbered series. No insertions of the pars lacrimalis or Horner's muscle on the saccus were found. These muscular fibres pass along the dorsal wall of the saccus and are separated from it by the reflex tendon of the ligamentum palpebrale mediale. The only muscular fibres that insert on the saccus are those that approach the anterior face of the saccus and the fornix. The fibres that insert on the anterior face proceed from the deep bundles of the pars preseptalis of the lower eyelids, and those that insert on the fornix derive from the deep bundles of the pars preseptalis of the upper eyelid.     

Electrical stimulation of glossopharyngeal nerve and oesophageal EMG response in the pigeon

The effects of the efferent glossopharyngeal nerve stimulation, on EMG activity of the pigeon cervical oesophagus, were studied. In control animals, stimulation caused a biphasic response characterized by an intra-stimulus excitatory component followed by a post-stimulus inhibitory one. The EMG response to glossopharyngeal stimulation appeared simultaneously throughout the cervical oesophagus. A bell-shaped mechanical wave was detected relating to the electrical excitatory component. Atropine administration antagonized the excitatory component, while the inhibitory one persisted. It occurs intra-stimulus, and its duration is increased, compared to control ones. A reduction in the oesophageal resting pressure was observed relating to the electrical inhibitory component. Hexamethonium caused complete disappearance of any EMG response to glossopharyngeal stimulation, as well as suppression of mechanical responses. The comparison between the EMG responses to swallow and to efferent glossopharyngeal stimulation suggests that in pigeon cervical oesophagus: primary peristalsis is central in origin; a dual system of glossopharyngeal fibres, excitatory and inhibitory, carries the central control for oesophageal motility; these excitatory and inhibitory fibres supply the oesophageal muscle via intramural neurons; the synaptic arrangement of the inhibitory pathway is more complex than the excitatory one.     

Anatomy of the external anal sphincter in man

The anatomy of the external anal sphincter was studied in 20 adult human cadavers of both sexes by dissection and histological examination. The external anal sphincter is not naturally divided into layers or laminae. The lowermost muscle bundles differ from the main part in being completely surrounded by thick fibrous tissue septa derived form the longitudinal anal coat. The perineal branch of S4 supplies the posterior third, the inferior haemorrhoidal nerves supply the anterior two thirds. All fibres of the sphincter retain their skeletal attachment to the anococcygeal ligament to the coccyx. Some fibres cross the median plane to be continuous with the transversus perinei of the opposite side. A cleft was displayed separating the lower border of the levator ani muscle from the upper border of the external anal sphincter. The muscle bundles of the sphincter are arranged circumferentially in one continuous circle and not in loops. Fibres from the anterior border of the levator ani muscle extend to cover and blend with the outer surface of the external sphincter in their way to the anococcygeal ligament.     

A histological and histochemical study of the oesophagus and oesogaster of the Senegal sole, Solea senegalensis.

A histological and histochemical study was performed in the buccal cavity and papillae, which were around the teeth, as well as in the oesophagus and oesogaster of the Senegal sole, Solea senegalensis adult specimens. The oesophagus and oesogaster were made up of four distinct layers: mucosa, submucosa, muscular and serous. Two morphological types of epithelial cells were distinguishable in the oesophageal mucosa: the more numerous type cells possessed an electron-dense cytoplasm, whereas the cytoplasm was electron-clear in the other cells. Mucus-secreting cells were the dominant feature of the epithelium throughout the oesophagus. These goblet cells were filled with numerous mucous droplets of low electron-density. The oesophagus was devoid of taste buds. In the oesogaster mucosa, three types of cells were distinguished: dark, rodlet and light epithelial cells. Dark epithelial cells showed different characteristics from that in the oesophagus: the nucleus was irregular with an electron-dense hyaloplasm, the cytoplasm had a scarce smooth and granular endoplasmic reticulum; a Golgi apparatus consisted of four parallel cisternae, dense granules without membrane, lysosomes and numerous mitochondria. The rodlet cells were elongated, contained rod-like structures and were surrounded by an electron-dense capsule-like structure. The bulk of the rodlet cell was composed of up to 20 extended rodlet units. Light epithelial cells of the oesogaster had the same characteristics as those observed in the oesophagus and contained numerous mitochondria with a dense matrix, abundant smooth endoplasmic reticulum and numerous vesicles. In the goblet cells of the papillae, sulfomucin was recognised, since they showed alcianophilia (alcian blue pH 1.0 and 0.5). These cells were negative to protein reaction (bromophenol blue) and contained -S-S- and SH groups. Enzymatic activities (alkaline phosphatase, acid phosphatase, ATPase (pH 7.2 and 9.4) and lipid reactions were negative in the goblet cells of the buccal cavity. Epithelial cells of oesophagus contained a weak presence of acid and neutral mucopolysaccharides. Oesophageal goblet cells contained carboxylated, sulphated (weakly and strongly ionised) mucosubstances and sialic acid. Most goblet cells did not contain proteins and presented disulphide (-S-S-) and sulphydril (-SH) groups. Proteins in general, and in particular those rich in lysine, tyrosine and arginine were present in the epithelium, lamina propria, submucosa and muscular layer of the oesophagus. Lipids in general and phospholipids were observed in the oesophageal epithelium while unsaturated, acid and neutral lipids were not observed. The lamina propria and submucosa contained a weak presence of phospholipids and unsaturated lipids. Acid phosphatase and ATPase (pH 7.2) activities were observed in the lamina propria, submucosa and muscular regions, while ATPase (pH 9.2) activity was weak in these areas. ATPase activity (pH 7.2 and 9.5) was very weak in the epithelium. Oesophageal goblet cells were negative to lipid and enzymatic reactions.     

The fibre type composition of the striated muscle of the oesophagus in ruminants and carnivores

The fibre type composition of the striated muscle layer of the oesophagus of the cow, sheep, donkey, dog and cat was examined with standard histochemical methods and immunohistochemical staining using type-specific antimyosin sera. The heavy chain and light chain composition of oesophageal myosin was also examined using electrophoretic peptide mapping and 2-dimensional gel electrophoresis respectively. In the ruminants and donkey the oesophagus was composed of fibre types I, IIA and IIC with immunohistochemical characteristics identical to those of the same fibre types found in control skeletal muscle. In the ruminants there was a gradient in the proportion of type I fibres from 1% (at the cervical end) to about 30% (at the caudal end). In the carnivores the oesophageal muscle was composed of a very small percentage of type I and IIC fibres, but the predominant type was very different histochemically and immunohistochemically from all the fibre types (I, IIA, IIB, IIC) present in the control muscles. This oesophageal fibre type ( IIoes ) had an acid- and alkaline-stable m-ATPase activity, a moderate histochemical Ca-Mg actomyosin ATPase activity, and reacted weakly with anti-IIA and anti-IIB myosin sera. Although the light chains of the IIoes myosin were the same as the light chains of a mixture of IIA and IIB myosins, their respective heavy chains gave different peptide maps. Greater differences were obtained between the heavy chains of IIoes and other striated muscle myosins. These observations lead us to conclude that this predominant fibre type of the carnivore oesophageal striated muscle is of the 'fast' type, and contains a distinct isoform of myosin similar but not identical to the other fast type myosins.     

The differentiation of cytotoxic T lymphocytes in vitro

Summary Previous neurohistological studies have been extended to include the structures contained solely or mainly within the junctional esophageal segment which may play an important role in the sphincter mechanism. The main findings were: 1) a progressive cranio-caudal thickening of the muscularis mucosae; 2) a conspicuous thickening of the circular muscle layer; 3) abundant and close interconnections between the esophageal striated fibres and gastric smooth muscle cells; 4) presence of annulo-spiral elastic fibres coiled around bundles of striated musculature; 5) increase of the intramural nerve component, particularly Auerbach's plexus, which consisted of a continuous nervous layer containing twice as many neurocytes as found in the upper esophageal segments; 6) presence of numerous interconnected motor endplates often possessing ultraexpansional fibres and secondary endplates. The findings are discussed with emphasis on functional correlations in order to attain a unitary morpho-functional view.Abbreviations used LES lower esophageal sphincter - HPZ high pressure zone; mm: muscularis mucosae - CNS central nervous system - CCK-PZ cholecystokinin-pancreozymin Dedicated to Prof. Dr. Wolfgang Bargmann for his fundamental contributions to Comparative Morphology     

Megaoesophagus in the mouse: histochemical and ultrastructural studies

Histochemical and ultrastructural studies of the muscle coat of the oesophagus from ICRC/HiCri mice (with megaoesophagus) and DBA/2fNCri mice (normal oesophagus) were carried out. The striking observation from histochemical studies was the presence of smooth muscle in the abdominal segment of the oesophagus from ICRC mouse in contrast to the control strain where smooth muscle was present only in the lowermost portion adjoining the stomach. Ultrastructural studies of the oesophageal wall from 5- and 10-day-old ICRC mice revealed an apparently normal muscle coat. In 3-month-old ICRC mice the upper abdominal segment of the oesophagus showed several abnormalities of smooth muscle fibres and paucity of plexus tissue accompanied by interstitial collagen deposition. The abnormalities were more severe in 1-year-old animals and were seen throughout the abdominal segment. From this study it is suggested that the primary cause of megaoesophagus in ICRC mice is neurogenic and not myogenic.     

The fibre type composition of the striated muscle of the oesophagus in ruminants and carnivores

Summary The fibre type composition of the striated muscle layer of the oesophagus of the cow, sheep, donkey, dog and cat was examined with standard histochemical methods and immunohistochemical staining using type-specific antimyosin sera. The heavy chain and light chain composition of oesophageal myosin was also examined using electrophoretic peptide mapping and 2-dimensional gel electrophoresis respectively. In the ruminants and donkey the oesophagus was composed of fibre types I, IIA and IIC with immunohistochemical characteristics identical to those of the same fibre types found in control skeletal muscle. In the ruminants there was a gradient in the proportion of type I fibres from 1% (at the cervical end) to about 30% (at the caudal end).In the carnivores the oesophageal muscle was composed of a very small percentage of type I and IIC fibres, but the predominant type was very different hisotchemically and immunohistochemically from all the fibre types (I, IIA, IIB, IIC) present in the control muscles. This oesophageal fibre type (IIoes) had an acid- and alkaline-stable m-ATP-ase activity, a moderate histochemical Ca-Mg actomyosin ATPase activity, and reacted weakly with anti-IIA and antiIIB myosin sera. Although the light chains of the IIoes myosin were the same as the light chains of a mixture of IIA and IIB myosins, their respective heavy chains gave different peptide maps. Greater differences were obtained between the heavy chains of IIoes and other striated muscle myosins.These observations lead us to conclude that this predominant fibre type of the carnivore oesophageal striated muscle is of the fast type, and contains a distinct isoform of myosin similr but not identical to the other fast type myosins.     

Ultrastructural Studies of the Visceral Muscles of Chaetognaths

The visceral musculature of Chaetognaths was studied with special attention given to the digestive apparatus muscle. In the head the digestive apparatus muscle is relatively thick; individual muscles are difficult to distinguish at the anatomical level; in the anterior part of the oesophagus discontinuous bundles and layers of cross-striated fibers are found. As a group however, the oesophageal musculature completely covers the oesophageal epithelium. The prominent muscle layers around the oesophagus probably help to force food into the intestine against the turgor pressure of the trunk cavity which tends to collapse the intestine. Around the intestine the musculature is largely circular and smooth. The intestinal epithelium is ciliated despite its muscular covering. Muscle fibers are not individually innervated. They form myoepithelial structures with various intercellular junction types. In the intestinal muscle the fibers show myoendothelial-like junctions. Sphincters composed of myoepidermal cells surround the anus and the female gonopores. The somatic side of the general cavity is lined with a polymorphic squamous epithelium. Sometimes myoepithelial cells are found, with the occasional presence of extracellular matrix basal to the layer of the squamous epithelium. The ontogenetic relations between the polymorphic epithelium and the composite ‘mesenteries’ remain to be established. We have now some idea about the architecture of the body of Chaetognaths in relation to contractile structures.     

Evidence for extrinsic control of oesophageal primary peristalsis

The r?le of both peripheral and central mechanism in the control of primary peristalsis was studied in pigeon cervical oesophagus. The results from the transection of oesophageal muscular wall and of extrinsic nerves suggest that: primary peristalsis is programmed centrally. extrinsic motor input is carried in glossopharyngeal nerves and distributed separately at each oesophageal level through intramural neurons. intramural neurons do not seem capable of propagating the peristaltic sequence irrespective of the central control.     

Inhibitory effect of sildenafil on gastrointestinal smooth muscle: role of NO-cGMP transduction pathway

Nitric oxide (NO) is an important neurotransmitter in the gut and has been demonstrated to be a key physiological mediator of non-adrenergic non-cholinergic (NANC) relaxation of gastrointestinal smooth muscle. In the present study the effect of PDE 5 inhibitor sildenafil on the gastrointestinal function (gastric emptying and intestinal transit) has been demonstrated in mice. Sildenafil (0.5-2 mg/kg, po) did not alter the percent gastric emptying however, in higher doses (5, 10 and 30 mg/kg, po) it inhibited the gastric emptying. On acute administration (0.5-5 mg/kg, po) it did not alter the intestinal transit but in higher doses (10 and 30 mg/kg, p.o.) delayed the intestinal transit. Further, the inhibitory effect of sildenafil was significantly blocked by L-NAME (10 mg/kg, ip), a non-selective NOS inhibitor and methylene blue (1 mg/kg, ip), a guanylate cyclase inhibitor. These findings suggest the participation of NO-cGMP transduction pathway in the inhibitory effect of sildenafil (higher doses) on the gastrointestinal smooth muscles and its potential application in patients with nutcracker oesophagus, hypertensive lower oesophageal sphincter (LOS), achalsia and diabetic gastroparesis or colitis where there is a loss of nNOS.     

日本沼虾消化道形态和组织学特点

应用石蜡切片和扫描电镜技术对日本沼虾消化道进行了研究。结果表明,食道壁向腔内形成四个纵突,食道上皮由单层柱状细胞构成,上皮下的结缔组织中具有放射肌和皮肤腺,环肌层近于连续。食道和胃连结处的管腔背方具食道瓣,胃内具胃磨、滤器和滤沟等结构,胃的组织学结构中除无皮肤腺分布外与食道相似。中肠较长,约占整个消化道的７１７％,具一对中肠前盲囊。中肠上皮细胞大致有两种类型,基膜着色深,环肌层连续,纵肌成束分散排列。后肠为一短管,管腔呈迷路状,其中部为一球形膨大的直肠。后肠的组织学结构与前肠相似。