5-Hydroxytryptamine-4 receptor messenger ribonucleic acid levels and densities in gastrointestinal muscle layers from healthy dairy cows

Serotonin (5-hydroxytryptamine, 5-HT) is involved in gastrointestinal tract (GIT) motor functions through binding to specific receptors located in the GIT walls. The objectives of the current study were to compare mRNA levels and binding sites of 5-HT(4) receptors (5-HTR(4)) in smooth muscle layers from the fundus abomasi, pylorus, ileum, cecum, proximal loop of the ascending colon (PLAC), and external loop of the spiral colon (ELSC) of healthy dairy cows, and to verify whether mRNA and protein expression were correlated. Smooth muscle samples were prepared by scraping the mucosa and submucosa from full-thickness intestinal wall samples. The mRNA levels of 5-HTR(4) were measured by real-time PCR and expressed relative to those of the housekeeping gene glyceraldehyde phosphate dehydrogenase. Binding studies were performed using the 5-HTR(4) antagonist [(3)H]GR113808. The mRNA levels of 5-HTR(4) were affected (P < 0.05) by location along the GIT. The mRNA levels of 5-HTR(4) in the ELSC and the ileum were greater than in the PLAC (P = 0.05 and P = 0.07, respectively) but similar to those of all other locations. The competitive binding of [(3)H]GR113808 to suspended membranes from the fundus abomasi, pylorus, cecum, and ELSC was best fit by a 2-site receptor model, whereas it was best fit by a 1-site receptor model in the ileum and PLAC. The mRNA levels and numbers of 5-HTR(4) were not correlated (r = 0.14; P = 0.71). In conclusion, mRNA and binding sites for 5-HTR(4) are present in the smooth muscle layer of the entire GIT of dairy cows and may play a role with respect to motility. The effects of activation of this receptor subtype may be different among GIT locations due to differences in the amount of high- relative to low-affinity binding sites.     

Concentration of volatile fatty acids in digesta samples obtained from healthy cows and cows with cecal dilatation or dislocation

OBJECTIVE: To compare concentrations of acetic, propionic, butyric, and i- and n-valerianic acids in digesta samples obtained from the rumen, cecum, proximal loop of the ascending colon (PLAC), and rectum of healthy cows and cows with cecal dilatation or dislocation (CDD). ANIMALS: 20 cows with CDD and 20 healthy cows. PROCEDURE: Samples were collected from all sites during surgical correction of CDD and also from the rectum 1, 2, and 3 days after surgery (group CDD). Samples from healthy (control) cows, matched on the basis of diet and milk yield, were obtained at a slaughterhouse. Concentrations of volatile fatty acids (VFA) were analyzed by use of gas chromatography. Absolute concentration of each VFA was additionally corrected for pH to allow calculation of the concentration of undissociated VFA. RESULTS: Absolute concentration and concentration of the undissociated form of all analyzed VFA were significantly increased in samples collected from the cecum and PLAC of cows in group CDD, compared with concentrations for control cows. Within 3 days after surgery, significant decreases of the absolute concentration of butyric, i- and n-valerianic acids, and undissociated i- and n-valerianic acids were evident in samples obtained from the rectum of group-CDD cows. Concentrations of VFA in samples obtained from the rectum during surgery correlated with corresponding VFA concentrations in samples obtained from the PLAC. CONCLUSIONS: Concentrations of VFA are increased in the cecum and PLAC of cows with CDD. However, the role of increased concentrations of VFA in the etiopathogenesis of CDD is unknown.     

Myoelectric activity in the intestine of cows with strangulating obstruction of the distal small intestine

Myoelectric activity in 2 cows instrumented with permanent electrodes in the ileum, cecum, proximal loop of the ascending colon (PLAC), and spiral colon was analyzed after an obstruction developed in the distal small intestine. Results were compared with patterns from a group of 7 normal cows. Myoelectric activity in the ileum immediately orad to the occlusion was characterized by abolition of the migrating myoelectric complex (MMC) and a constant pattern of strong spike bursts of long duration. Cyclic activity was present in all parts of the large intestine, and propagation of phase III activity was evident from proximal to distal. A slight degree of disorganization in phase III propagation was restricted to the spiral colon. Activity cycles tended to be shorter in the cecum and PLAC of both cows with colic than in normal cows, and the intensity of spiking activity was generally lower. Changes in duration of the MMC in the spiral colon (bovine colonic MMC, bcMMC) were inconsistent, but the intensity of spiking activity tended to be lower in phases I and II of both cows compared to controls. The organization of phase III in several spindles typical of the bovine spiral colon was not disrupted, but phase IV of the bcMMC occurred only infrequently. Organized cyclic activity occurred in the large intestine of both cows despite complete disruption of the small intestinal MMC, indicating the presence of mechanisms able to initiate and regulate coordinated myoelectric patterns in the large intestine independent of the small intestine.     

Myoelectric activity of the spiral colon in dairy cows

OBJECTIVE: To describe myoelectric activity of the spiral colon in healthy cows. ANIMALS: 7 lactating Simmental X Red-Holstein crossbred cows. PROCEDURE: Cows were implanted with 7 pairs of bipolar silver electrodes (4 in the spiral colon and 1 each in the cecum, distal part of the ileum, and proximal loop of the ascending colon [PLAC]). Myo-electric activity was recorded during 4 days for each cow. Patterns were analyzed, using computer-based methods. RESULTS: Myoelectric activity of the spiral colon was closely associated with motility of the ileum and PLAC and showed the typical organization of migrating myoelectric complexes (MMC). The MMC in the bovine spiral colon (bcMMC) had a mean +/- SD duration of 188.6 +/- 30.8 minutes and was divided into 4 phases. Phases I and II lasted 11.3 +/- 1.4 and 159.4 +/- 33.3 minutes, respectively. Phase III (duration, 5.4 +/- 1.2 minutes) was characterized by 5.2 +/- 0.9 regular spindles (35.4 +/- 5.4 seconds) and 1 final elongated spindle (137.2 +/- 56.4 seconds). Phase III most commonly (73.8 +/- 16.1%) was followed by phase IV (duration, 173 +/- 3.6 minutes). Propagation velocity of phase III was 4.4 +/- 0.5 cm/min, and 13.6% of bcMMC were incompletely propagated through the spiral colon. CONCLUSIONS: Myoelectric activity of the bovine spiral colon is composed of a recurring cyclic pattern similar to MMC of the small intestine. Data of colonic myoelectric activity in healthy cows will serve as a basis for studies on cecal dilatation and dislocation in cattle.     

Myoelectric activity in the intestines of healthy dairy cows during the recovery period after implantation of permanent electrodes

OBJECTIVE: To describe myoelectric patterns in the intestines of cows after electrode implantation. ANIMALS: 7 lactating Simmental-Red Holstein cows. PROCEDURE: Cows were implanted with 7 pairs of bipolar silver electrodes (1 each in the ileum, cecum, and proximal loop of the ascending colon (PLAC) and 4 in the spiral colon). Myoelectric activity was monitored during 10 periods within the first 3 weeks after surgery. Recordings from the first 2 weeks were compared with recordings from the third week, which was considered a steady-state condition. RESULTS: Significant changes over time were detected for 18 of 57 variables, including 3 variables describing myoelectric activity of the ileum, 6 variables of the cecum, 6 variables of the PLAC, and 3 variables of the spiral colon. Compared with values for the steady-state condition, 16 variables differed significantly for the 14-day period after surgery (7 variables until day 11, 2 variables until day 8, 4 variables until day 5, 1 variable until day 3, and 2 variables until day 2 after electrode implantation). None of the variables had significant changes that lasted only 1 day after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Significant changes were observed for several variables of myoelectric activity in all intestinal segments until as late as 11 days after electrode implantation, whereas a steady-state condition was reached 14 days after surgery. Effects of drugs, manipulations, or nutrition regimens on myoelectric activity of the bovine digestive tract should be evaluated no sooner than 2 weeks after electrode implantation.     

Distribution of muscarinic receptor subtypes and interstitial cells of Cajal in the gastrointestinal tract of healthy dairy cows

OBJECTIVE: To describe the distribution of muscarinic receptor subtypes M(1) to M(5) and interstitial cells of Cajal (ICCs) in the gastrointestinal tract of healthy dairy cows. SAMPLE POPULATION: Full-thickness samples were collected from the fundus, corpus, and pyloric part of the abomasum and from the duodenum, ileum, cecum, proximal loop of the ascending colon, and both external loops of the spiral colon of 5 healthy dairy cows after slaughter. PROCEDURES: Samples were fixed in paraformaldehyde and embedded in paraffin. Muscarinic receptor subtypes and ICCs were identified by immunohistochemical analysis. RESULTS: Staining for M(1) receptors was found in the submucosal plexus and myenteric plexus. Antibodies against M(2) receptors stained nuclei of smooth muscle cells only. Evidence of M(3) receptors was found in the lamina propria, in intramuscular neuronal terminals, on intermuscular nerve fibers, and on myocytes of microvessels. There was no staining for M(4) receptors. Staining for M(5) receptors was evident in the myocytes of microvessels and in smooth muscle cells. The ICCs were detected in the myenteric plexus and within smooth muscle layers. Distribution among locations of the bovine gastrointestinal tract did not differ for muscarinic receptor subtypes or ICCs. CONCLUSIONS AND CLINICAL RELEVANCE: The broad distribution of M(1), M(3), M(5), and ICCs in the bovine gastrointestinal tract indicated that these components are likely to play an important role in the regulation of gastrointestinal tract motility in healthy dairy cows. Muscarinic receptors and ICCs may be implicated in the pathogenesis of motility disorders, such as abomasal displacement and cecal dilatation-dislocation.     

Effects of erythromycin on myoelectric activity of the spiral colon of dairy cows

The effects of erythromycin on myoelectric activity of the spiral colon of dairy cows were investigated in a prospective study. Four Simmental x Red-Holstein crossbred cows of similar body weight and condition with seven pairs of bipolar electrodes implanted in the intestine (one each in the distal ileum, caecum and proximal colon, and four in the spiral colon) were included. Erythromycin lactobionate (1 mg kg(-1)) and 0.9% sodium chloride solution (NaCl) were administered to each cow in a random order. Erythromycin was diluted with NaCl and both treatments were administered slowly intravenously over a period of 5 min 1 h after onset of a phase III of the bovine colonic migrating myoelectric complex (bcMMC). A 3-6-day washout period was scheduled between trials. Significant differences between the results of the treatments were observed for spike duration in phase I as well as for spike duration and duration of spiking activity during phase II of the second bcMMC, which were significantly higher after erythromycin treatment than after NaCl. These findings suggest an indirect effect of erythromycin on colonic motility in cattle.     

Ultrasonographic findings in cows with dilatation, torsion and retroflexion of the caecum

Thirty cows with caecal dilatation underwent clinical and ultrasonographic examinations, followed by a right flank laparotomy and surgical correction. The intraoperative findings were compared with the results of the ultrasonographic examination. The appearance, position, dimensions, diameter and nature of the contents of the caecum and proximal and spiral ansa of the colon were determined with a 3.5 MHz linear transducer. The wall of the proximal ansa of the colon and of the dilated caecum closest to the abdominal wall was visible in all the cows and appeared as an echogenic semicircular line immediately adjacent to the peritoneum. The contents of the caecum and of the proximal and spiral ansa of the colon were not visible in 21, 25 and 25 cows, respectively, owing to gas. In the remaining cows, the contents were hypoechogenic to echogenic in appearance. In all of the cows, the dilated caecum was imaged from the right abdominal wall at the level of the tuber coxae. The caecum was imaged from the 12th, 11th and 10th intercostal spaces in 11, five and three cows, respectively. The caecum and proximal ansa of the colon were situated immediately adjacent to the right abdominal wall in 28 cows, but in the other two cows parts of these structures were pushed away from the abdominal wall by the liver or gall bladder. The diameter of the caecum, measured at various sites varied from 7.0 to 25.0 cm. Caecal dilatation was diagnosed on the basis of the results of rectal examinations in 28 of the cows, but in all 30 cows on the basis of the results of the ultrasonographic examinations. Dilatation and caudal displacement of the caecum were diagnosed in 18 cows; dilatation and cranioventral retroflexion of the caecum were diagnosed in six cows, and dilatation and craniodorsal retroflexion of the caecum were diagnosed in two cows. In the four other cows, the direction of the retroflexed caecum could not be determined. The diagnosis of caecal dilatation based on the ultrasonographic findings was confirmed in all the cows during exploratory laparotomy. The results of ultrasonography and exploratory surgery with regard to the position of the dilated and sometimes retroflexed or twisted caecum were in complete agreement in 18 cases, in partial agreement in eight cases, but in four cases did not agree.     

Obstruction of the Ascending Colon in Cattle: II. An Experimental Model of Partial Bypass of the Large Intestine

Four dairy calves were subjected to partial bypass of the large intestine by uniting the ileum to the distal centrifugal coil of the spiral loop of the ascending colon (spiral colon). Digesta bypassed the distal ileum, cecum, proximal loop of the ascending colon, and the centripetal coils of the spiral colon. The calves survived the surgical procedure and were healthy throughout the 4-week postoperative experimental period. Feces were loose immediately after bypass, but fecal dry matter (DM) gradually increased over the subsequent 2 weeks (P < 0.01), indicating adaptation of remaining bowel to absorb more water. There was no significant change in serum concentration of sodium or chloride. The calves continued to grow and gain weight at acceptable rates after bypass. Necropsy of 3 of the calves demonstrated a decrease in size of the bypassed bowel.     

Expression and localisation of calbindin D28k in all intestinal segments of the laying hen

1. The aim of the present study was to investigate expression and localisation of a 28-kDa calcium-binding protein (CaBP-D28k) related to active calcium (Ca) absorption, in the entire intestine of egg-laying hens. 2. Western blotting analysis showed that the entire intestine expressed CaBP-D28k to the following degree: duodenum > jejunum > caecum > ileum > colon. Immunohistochemistry showed strong CaBP-D28k localisation in enterocytes along the villus tip-crypt axis in the duodenum and in villus tips in the caecum and colon. The jejunum and ileum had moderate localisation with respect to the number of immunoreactive cells and staining intensity. 3. These results suggest that laying hens actively absorb Ca in both the large and small intestines.     

New aspects on the etiopathogenesis and treatment of cecal dilatation/-dislocation in cows--a review]

This paper describes the latest results of research in the areas of etiopathogenesis and treatment of cecal dilatation/-dislocation (CDD) in cows. Similar etiopathogenic mechanisms of CDD and displacement of the abomasum, as has been hypothesized in the literature, were not confirmed. Spontaneous CDD is most likely the consequence of a dysfunction of the spiral colon. Bethanechol is an appropriate motility-modulating drug for medical and postsurgical treatment of spontaneous CDD.     

Ultrasonographic examination of the caecum and the proximal and spiral ansa of the colon of cattle

The large intestine of 10 cows was examined from the right abdominal wall with a 3.5 MHz linear transducer. The cows were then slaughtered, and the organs were re-examined in a water bath. The caecum was visualised from the middle region of the abdominal wall. It ran caudo-cranially, varied in diameter from 5.2 to 18.0 cm and was situated immediately adjacent to the abdominal wall. The lateral wall of the caecum appeared as a thick, echogenic, crescent-shaped line. It could be visualised as far cranially as the 12th intercostal space. Although its junction could not be identified, the proximal ansa of the colon was recognised on the basis of its anatomical position and its diameter, which was smaller than that of the caecum. The spiral ansa of the colon and the descending colon were situated dorsal to the caecum and could be identified by moving the transducer horizontally along the abdominal wall to the last rib. The spiral ansa of the colon was situated ventral to the descending colon, and its walls appeared as thick echogenic lines. In a contracted state, the spiral colon had the appearance of a garland.     

Uptake of ferritin by follicle-associated epithelium in the colon of calves.

Uptake of macromolecules (e.g., ferritin) by M cells in follicle-associated epithelium in small and large intestine was investigated in three healthy, conventionally raised, 2- to 3-week-old, female Holstein Frisian calves. A 2.5% solution of ferritin was injected into the ligated loops in mid-jejunum, in terminal ileum, in the ascending colon adjacent to the ileocecal junction, and in the proximal loop of the ascending colon containing gut-associated lymphoid tissue. After exposure times that ranged from 82 to 165 minutes, ferritin was detected in M cells of domes in the small intestine, as well as in cells in follicle-associated epithelium of proprial lymphoid nodules and lymphoglandular complexes of colon that morphologically resembled M cells of small intestine. Ferritin was found in apical invaginations, apical vesicles, multivesicular bodies, basal vesicles, and adjacent intercellular spaces. In addition to ferritin, apical vesicles, multivesicular bodies, and intercellular spaces contained 50-nm membrane-bound particles. More ferritin was endocytosed by M cells of the small intestine than by M cells of the large intestine. In the large intestine, higher amounts of ferritin were found in M cells of follicle-associated epithelium overlying proprial lymphoid nodules than in M cells of follicle-associated epithelium in the depth of lymphoglandular complexes. Based on these results, we concluded that M cells of follicle-associated epithelium in the colon of calves provide a route for antigen uptake into the intestinal lymphoid system.     

肠艾美耳球虫配子生殖与病理变化

用单个肠艾美耳球虫Eimeria intestimalis Cheissin 1984卵囊感染无球虫兔,获得纯种进行研究。1.肠艾美耳球虫的配子生殖阶段寄生于空肠和回肠,此时宿主组织有较严重病变。12指肠、结肠和盲肠未见虫体,但在感染后264小时见盲肠的个别绒毛内有1～3个配子体,可能属偶然现象。2.感染后180小时发现极少数早期配子体,感染后192小时出现少量配子体寄生在空肠和回肠的绒毛和腺上皮细胞内,感染后216至264小时,绒毛上皮和腺上皮细胞内多为配子体、合子和卵囊所取代。感染后216小时出现极少量卵囊,264小时则见有大量卵囊。3.感染开始时(感染后61～73小时),回肠、空肠绒毛上皮正常;腺上皮细胞出现少量滋养体和裂殖体。96至192小时后,肠绒毛上皮和腺上皮受侵害程度渐趋严重,肠绒毛变矮,绒毛上皮及腺上皮细胞肿大变空,细胞核消失。许多腺泡塌陷。感染后216～264小时,肠绒毛受侵害最为严重,空肠和回肠绒毛萎缩或消失,变为一层矮柱或立方形上皮细胞或全无上皮细胞覆盖的绒毛。固有层均质红染,或颗粒状。肠腺塌陷,数量减少,大小不一。腺腔内见有配子体、合子或卵囊残留,部分腺泡上皮细胞再生,细胞核增生成堆。12指肠、盲肠和结肠正常。     

Fatty acid profiles in relation to triglyceride level in the liver of dairy cows

To elucidate possible relationships between triglyceride (TG) levels and fatty acid composition in bovine liver, hepatic TG and seven individual fatty acids were measured in 23 Holstein dairy cows, of them 6 are healthy. Liver TG level was greater than 3 % in 12 cows which were ruled fatty liver. Palmitic and oleic acid proportions were significantly higher in fatty liver cows than in the healthy cows, while stearic acid was lower in fatty liver cows. With increased liver TG, stearic acid proportions decreased dramatically. Results indicate that hepatic lipidosis markedly alters the proportions of the various fatty acids in the liver of dairy cows.     

Prokinetic effects of cisapride, naloxone and parasympathetic stimulation at the equine ileo-caeco-colonic junction

The electromyogram of the terminal ileum, the caecum and the proximal right ventral colon was recorded in fasted conscious ponies receiving intravenously equiactive doses of pilocarpine (0.05 mg/kg) and carbachol (0.01 mg/kg) as acetylcholine analogues; cisapride (0.1 mg/kg) and metoclopramide (2 mg/kg) facilitating acetylcholine release from myenteric neurones and naloxone (0.05 mg/kg) as an antagonist of the endogenous inhibitory opioid system. Both cisapride and naloxone induced typical migrating spike bursts in the colon associated with contractions of caecal body and caecal base. Both pilocarpine and carbachol stimulated the terminal ileum but had opposite effects on the activity of the caeco-colonic segment which was decreased by pilocarpine and increased by carbachol. High doses of metoclopramide had weak and unspecific stimulatory motor effects. It is concluded that a true prokinetic effect at the equine ileo-caeco-colonic junction requires a motor profile which includes coordination between contractions sequentially involving the body and the base of the caecum and migrating spike bursts on the proximal colon. Such changes in the motor profile were produced by cisapride and naloxone and to a lesser extent by carbachol.