电刺激发情期大鼠蓝斑核对子宫平滑肌电活动的影响

在急性实验条件下,以爆发波(BW)的频率、波宽、峰电位频率为指标,观察了电刺激蓝斑核对发情期大鼠子宫平滑肌电活动的影响.结果:电刺激蓝斑核后,子宫角平滑肌BW频率增加极显著,波宽及峰电位频率虽有增加,但无显著差异;子宫颈平滑肌BW频率无显著增加,波宽却显著缩短,峰电位频率有所减少,未见明显差异.结果表明,蓝斑核对发情期大鼠子宫平滑肌电活动具有调节作用.     

电刺激发情期大鼠的蓝斑对子宫平滑肌电活动的影响

在急性实验条件下，以爆发（ＢＷ）的频率、波宽、峰电位频率为指标，观察了电刺激蓝斑核对发情期大鼠子宫平滑肌电活动的影响，结果：电刺激蓝斑核后，子宫角平滑肌ＢＷ频率增加极显著，波宽及峰电位频率虽有增加，但无显著差异；子宫颈平滑肌ＢＷ频率无显著增加，波宽却显著缩短，峰一频率有所减少，未见明显差异。结果表明，蓝斑核对发情期大鼠子宫平滑活动具有调节作用。     

电针“足三里”穴及刺激中脑导水管周围灰质对家兔结肠电的影响

以家兔近端结肠电的基本活动规律为指标,观察了电针足“三里”穴及刺激中脑导水管周围灰质(PAG)对近端结肠电的影响,同时对比观察了损毁部分PAG对电针效应的影响。结果:(1)在禁食、轻度麻醉状态下,近端结肠电慢波振幅为206±156μV,频率为14.9±1.7Hz,慢波上载有快波;(2)电针“足三里”穴对结肠电有抑制或兴奋效应,当有快渡活动时,主要呈现慢波振幅增加效应,有时也增加快波的振幅和幅度;而当没有快波活动时,电针主要减低慢波振幅。上述电针的作用可持续10～45min;(3)对44个pAG刺激点刺激的结果显示,16个点为结肠电兴奋点;13个为结肠电抑制点,而15个点为无效点。其中兴奋效应的潜伏期为1.1±0.95min,可持续2.45±1.4min;抑制效应的潜伏期为0.6±0.5min,可持续2.9±1.3min;(4)5只家兔损毁部分PAG后,电针效应减少23.8±16.6％。     

氯前列烯醇对乏情期绵羊子宫肌电活动的影响

采用浆膜表面埋植双极引导电极多道同时记录法 ,测定苯甲酸雌二醇 (E2 )诱导乏情期绵羊子宫体、子宫角肌电活动及氯前列烯醇(PGF2α)对它的影响。结果表明 :子宫肌电图 (EMG)呈节律性静、动复合波丛 ,平均峰电峰值子宫体为 (14 7 58± 33 54) μV ,子宫角为 (138 36± 40 93) μV ;峰电频率子宫体为 (1 7 0 0± 1 2 5)cpm ,子宫角为 (34 44± 3 1 8)cpm。在E2 对子宫EMG抑制 /兴奋双向作用的抑制阶段内PGF2α可以显著增加子宫体肌电活动的峰电频率 (2 7 93± 5 35)cpm ,(54 94± 7 88)cpm ,t =8 0 2 ,p <0 0 1 ) ,子宫体肌电活动比率增加了 2 10 68%(7 68,1 6 56) ;极显著地增加子宫角肌电活动的峰电频率 (35 62± 5 48)cpm ,(73 70± 2 7 74)cpm ,t=4 0 5 ,(p<0 0 1 ) ,子宫角肌电活动比率增加了 2 2 3 73%(1 4 92 ,33 38)。E2 与PGF2α在临床上配合使用能够显著地增加子宫的兴奋性     

不同机制介导怀牛膝兴奋未孕大鼠子宫平滑肌的峰电活动

在50只Wistar雌性未孕大鼠子宫角浆膜面上沿子宫纵轴埋植1对Ag-AgCl双极电有，腹腔注射阿托品或异搏定或消炎痛后，观察注射怀牛膝0.6mL夺未孕大鼠子宫平滑肌峰电活动的影响，探讨其兴奋的途径。结果表明，阿托品阻断胆碱能M受体后，腹腔注射怀牛膝水煎剂，子宫平滑肌峰电活动表现出明显的兴奋效应，搏定阻断L型Ca^2 通道（L－VDCC）后，腹腔注射怀牛膝水煎剂，暴发波的最大振幅等4项指标均无明显变化（P＞0．05），而单波的正波最大振幅和峰面积则有明显增加（P＜0．05），单波的负波最大振幅则无显著变化（P＞0．05）；腹腔注射前列腺素合成酶抑制剂消炎痛后，注射怀牛膝水煎剂，暴发波的最大振幅等4项指标变化不明显（P＞0．05），单波的正波最大振幅等3项指标均有明显升高（P＜0．05）。结果提示，怀牛膝对未孕大鼠子宫平滑肌峰电活动的兴奋作用是通过胆碱能M受体以外的其他途径实现的，部分可能与子宫平滑肌细胞膜上的异搏定敏感的L型Ca^2 通道有关，部分可能与刺激前列腺素合成与释放有关。     

双氯醇胺对山羊胃肠电活动及运动的影响

采用在瘤胃背囊、皱胃幽门部和十二指肠近端安装有双极胃肠电极及应力传感器的土种公山羊5头,按自身对照设计,研究了双氯醇胺对山羊胃肠电活动及运动的影响.结果表明,β-激动剂双氯醇胺在功能上有与肾上腺素相似的作用,即可直接或间接地抑制山羊胃肠道电活动和运动.与对照期相比,给山羊皮下注射双氟醇胺后,其瘤胃背囊、皱胃幽门部及十二指肠近端的快、慢波电位振幅显著降低(P＜0.05),瘤胃运动的应力波值极显著减小(P＜0.01),但快、慢波频率无明显变化.瘤胃运动的应力波值与瘤胃快波电位振幅以及应力波延续时间与快波峰电位数间呈强正相关(R值分别为0.94±0.32和0.85±0.27).体外试验结果亦显示,双氯醇胺可使离体十二指肠段的快、慢波电位振幅减小,张力波值大幅度下降,张力曲线变得平滑.     

发情周期不同阶段牦牛子宫中黄体生成素受体的表达变化

为研究发情周期不同阶段牦牛子宫中黄体生成索受体(LHR)的定位及表达变化,笔者利用免疫组织化学SP法分别检测发情期、发情后期、间情期和发情前期牦牛子宫中LHR的表达,并进行光密度值分析.结果表明,LHR免疫阳性产物在牦牛子宫腺上皮细胞、基质细胞、血管内皮细胞、血管平滑肌细胞和肌层平滑肌细胞中均有表达;腺上皮细胞、基质细胞和肌层平滑肌细胞中LHR在发情前期和发情期表达最弱,发情后期表达增加,间情期表达最强(P＜0.05);子宫内膜血管平滑肌细胞中LHR的表达在发情期最强,间情期最弱(P＜0.05);血管内皮中LHR在发情期和发情前期表达很强,发情后期和间情期显著下降(P＜0.05).结果表明LHR参与了发情周期不同阶段牦牛子宫功能变化的调控.     

犬子宫蓄脓病因学研究进展

犬子宫蓄脓是临床上常见的产科疾病,据临床症状可将其分为闭锁型子宫蓄脓和开放型子宫蓄脓。犬子宫蓄脓主要发生在犬发情后期,此期受孕酮浓度增加和雌激素浓度降低的影响,使子宫细胞的免疫水平降低。孕酮浓度增加使子宫内膜增生和腺体分泌增加,同样有利于外来细菌的生长、繁殖。子宫黏膜受到外来细菌的入侵发生病变,子宫分泌物增多。若在子宫颈关闭的情况下,不会有分泌物排出;但若子宫颈处于开放状态,则主要排出恶臭、多血的黏液脓性分泌物。另外,犬子宫蓄脓的发生与犬的年龄、品种可能也有一定的相关性。总之,犬子宫蓄脓是在子宫内膜囊性增生、孕酮对子宫内膜连续刺激和细菌感染等因素作用下的子宫炎性病变表现。     

雌二醇对雌性家兔十二指肠肌电活动的作用研究

拟阐明雌激素调节十二指肠运动的作用规律,并筛选和建立其浓度与十二指肠肌电活动监测指标的数学模型。通过构建试验家兔的卵巢摘除动物模型和电极埋置动物模型,肌注不同剂量的苯甲酸雌二醇,采用BL-420F生物机能试验系统分别记录各试验组家兔十二指肠肌电活动变化,并对结果进行统计分析,结合对各监测指标的函数拟合精度分析选择并构建苯甲酸雌二醇与十二指肠肌电活动监测指标最优的数学模型。结果表明,十二指肠肌电的振幅、频率与肌电活动指数均随苯甲酸雌二醇剂量的增加呈现出一种先升高后降低的变化趋势。通过对各监测指标进行分析、筛选,构建了雌二醇剂量与肌电活动指数关系的函数模型,对该函数进行分析后可知,肌电活动指数的变化范围为1.50~5.23mV·min~(-1),并在雌二醇剂量为0.098mg·kg~(-1)时肌电活动指数达到最大值5.23mV·min~(-1)。此外,以雌二醇剂量0.063、0.098、0.133mg·kg~(-1)为分界点,可将肌电活动指数随雌二醇剂量增加而变化的趋势分为指数型增加、对数型增加、指数型减小以及对数型减小四个区间段。上述结果表明雌二醇对十二指肠肌电活动呈现明显浓度依赖性双重调节作用,并且这种调节作用是在十二指肠本身具备一定水平的肌电活动的基础上进行的,即雌激素对十二指肠肌电活动的调节作用是间接的。此外十二指肠的肌电活动在不同浓度范围雌激素的作用下表现不同的变化趋势,呈现出明显的区间效应。本试验的研究结果为阐明雌激素在体内调节十二指肠运动的调节方式和雌激素类药物的研发和应用提供了一定理论依据和参考。     

犬听觉失匹配性负波研究

目前,动物脑电信号的研究仍停留在脑电图技术(EEG)本身,而少有对动物事件相关电位成分等方面的研究。本文通过微创操作获取犬脑电信号,以Oddball试验范式对犬进行听觉刺激,在犬的听觉事件相关电位信息中检测到了和人类相似的失匹配性负波(潜伏期:209 ms,局部峰振幅:-9.785μV),从脑电位信号变化的层面展示了犬脑对不同刺激处理的过程,证明了短纯音刺激的强度、频率与犬听觉MMN的出现不具备必然的联系,为下一步对犬脑自动加工,视觉、嗅觉事件相关电位的研究奠定了基础。     

Neurogenic and Myogenic Responses in Isolated Smooth Muscle of The Bovine Teat

Strips of bovine teat smooth muscle were studied. Their innervation was investigated with analytical pharmacology on field stimulated preparations. The content of noradrenaline in the teat wall and the sphincter region was determined. The main results were: teat smooth muscle has properties of single unit smooth muscle i.e. automaticity and active response to stretch. Especially the sphincter region is inclined to rapid phasic rhythmicity. The teat smooth muscle receives excitatory adrenergic innervation. The noradrenaline released from the nerves preferentially activates α-adrenoceptors, while β-adrenoceptors essentially are noninnervated and humoral. The sphincter region has a higher concentration of noradrenaline and a more intimate neuro-effector arrangement. This is probably of functional significance. Moderate chilling increases the response to adrenergic nerve stimulation while it is decreased at higher temperatures. This has most likely physiological importance. The results are discussed with respect to in vivo findings and it is concluded that the bovine teat smooth muscle with its excitatory adrenergic nerves forms a normally very efficient neuro-effector system with a particular strength in the sphincter around the streak canal.     

Repetitive stimulation of the common peroneal nerve as a diagnostic aid for botulism in foals

Background: Botulism is a potentially fatal paralytic disorder for which definitive diagnosis is difficult. Objectives: To determine if repetitive stimulation of the common peroneal nerve will aid in the diagnosis of botulism in foals. Animals: Four control and 3 affected foals. Methods: Validation of the test in healthy foals for its comparison in foals with suspected botulism. Controls were anesthetized and affected foals were sedated to avoid risks of anesthesia. The common peroneal nerve was chosen for its superficial location and easy access. Stimulating electrodes were placed along the common peroneal nerve. For recording, the active and reference electrodes were positioned over the midpoint and distal end of the extensor digitorum longus muscle, respectively. Repeated supramaximal stimulation of the nerve was performed utilizing a range of frequencies (1–50 Hz). Data analysis consisted of measuring the amplitude and area under the curve for each M wave and converting these values into percentages of decrement or increment based on the comparison of subsequent potentials to the initial one (baseline) within each set. Results: A decremental response was seen at all frequencies in control foals. Decremental responses also were observed in affected foals at low frequencies. An incremental response was seen in all affected foals at 50 Hz. Conclusions and Clinical Importance: Decreased baseline M wave amplitudes with incremental responses at high rates are supportive of botulism. Repetitive nerve stimulation is a safe, simple, fast, and noninvasive technique that can aid in the diagnosis of suspected botulism in foals.     

Lateral musculature in the whitemouth croaker (Micropogonias furnieri): its characterization with respect to different gonadal conditions

Histochemical and ultrastructural studies were performed on the lateral musculature from individual female whitemouth croaker, Micropogonias furnieri, at the anterior, medium and posterior regions. Based upon histochemical myosin-ATPase (m-ATPase) determination, diverse types of red, pink and white fibres were discerned. Red muscle had abundant mitochondria and stained intensely for aerobic enzymes, white muscle scarcely stained for the same enzymes and pink muscle responded in an intermediate manner. Both white and pink muscle had few mitochondria. The relative proportion of red muscle increased towards the caudal region; pink muscle diminished towards this region and white muscle modified its proportion only in the anterior region. m-ATPase activity showed differences in relation to the gonadal condition along the body, particularly in the white fibres at the anterior and medium regions.     

In vitro investigation of the effect of prostaglandins and nonsteroidal anti-inflammatory drugs on contractile activity of the equine smooth muscle of the dorsal colon, ventral colon, and pelvic flexure

OBJECTIVES: To determine the in vitro effect of prostaglandin E2 (PGE2), PGF2alpha, PGI2; and nonsteroidal anti-inflammatory drugs (NSAID; ie, flunixin meglumine, ketoprofen, carprofen, and phenylbutazone) on contractile activity of the equine dorsal colon, ventral colon, and pelvic flexure circular and longitudinal smooth muscle. ANIMALS: 26 healthy horses. PROCEDURE: Tissue collected from the ventral colon, dorsal colon, and pelvic flexure was cut into strips and mounted in a tissue bath system where contractile strength was determined. Incremental doses of PGE2, PGF2alpha,, PGI2, flunixin meglumine, carprofen, ketoprofen, and phenylbutazone were added to the baths, and the contractile activity was recorded for each location and orientation of smooth muscle. RESULTS: In substance P-stimulated tissues, PGE2 and PGF2alpha enhanced contractility in the longitudinal smooth muscle with a decrease or no effect on circular smooth muscle activity. Prostaglandin I2 inhibited the circular smooth muscle response with no effect on the longitudinal muscle. The activity of NSAID was predominantly inhibitory regardless of location or muscle orientation. CONCLUSIONS AND CLINICAL RELEVANCE: In the equine large intestine, exogenous prostaglandins had a variable effect on contractile activity, depending on the location in the colon and orientation of the smooth muscle. The administration of NSAID inhibited contractility, with flunixin meglumine generally inducing the most profound inhibition relative to the other NSAID evaluated in substance P-stimulated smooth muscle of the large intestine. The results of this study indicate that prolonged use of NSAID may potentially predispose horses to develop gastrointestinal tract stasis and subsequent impaction.     

In vitro effects of lidocaine on the contractility of equine jejunal smooth muscle challenged by ischaemia‐reperfusion injury

Reasons for performing study: Post operative ileus (POI) in horses is a severe complication after colic surgery. A commonly used prokinetic drug is lidocaine, which has been shown to have stimulatory effects on intestinal motility. The cellular mechanisms through which lidocaine affects smooth muscle activity are not yet known. Objectives: To examine the effects of lidocaine on smooth muscle in vitro and identify mechanisms by which it may affect the contractility of intestinal smooth muscle. Hypothesis: Ischaemia and reperfusion associated with intestinal strangulation can cause smooth muscle injury. Consequently, muscle cell functionality and contractile performance is decreased. Lidocaine can improve basic cell functions and thereby muscle cell contractility especially in ischaemia‐reperfusion‐challenged smooth muscle. Methods: To examine the effects of lidocaine on smooth muscle function directly, isometric force performance was measured in vitro in noninjured and in vivo ischaemia‐reperfusion injured smooth muscle tissues. Dose‐dependent response of lidocaine was measured in both samples. To assess membrane permeability as a marker of basic cell function, release of creatine kinase (CK) was measured by in vitro incubations. Results: Lidocaine‐stimulated contractility of ischaemia‐reperfusion injured smooth muscle was more pronounced than that of noninjured smooth muscle. A 3‐phasic dose‐dependency was observed with an initial recovery of contractility especially in ischaemia‐reperfusion injured smooth muscle followed by a plateau phase where contractility was maintained over a broad concentration range. CK release was decreased by lidocaine. Conclusion: Lidocaine may improve smooth muscle contractility and basic cell function by cellular repair mechanisms which are still unknown. Improving contractility of smooth muscle after ischaemia‐reperfusion injury is essential in recovery of propulsive intestinal motility. Potential relevance: Characterisation of the cellular mechanisms of effects of lidocaine, especially on ischaemia‐reperfusion injured smooth muscle, may lead to improved treatment strategies for horses with POI.     

Immunohistochemical Demonstration of Cytoskeletal Proteins in the Testis of the Japanese Black Bear, Ursus thibetanus japonicus

The seasonal changes of the cytoskeletal protein expressions were immunohistochemically investigated in the testes of Japanese black bear, Ursus thibetanus japonicus. A strong immunoreaction for α-smooth muscle actin is restricted to the vascular smooth muscle cells and the peritubular cells which surround the seminiferous tubules by several layers throughout the year. Weak immunoreactions for B4 antigen and desmin were observed in the vascular smooth muscle cells and in a part of peritubular cells throughout the year. A strong immunoreaction for vimentin was also detected in the fibroblasts and Leydig cells, in addition to the vascular smooth muscle and epithelial cells and the peritubular cells throughout the year. A strong α-tubulin immunoreaction was detected in the elongating spermatids during the acrosome phase of spermiogenesis in May and June. The cytoplasm of several Sertoli cells was faintly immunoreacted for vimentin in the basal and lateral region, while an intense α-tubulin reaction was seen in the entire cytoplasm in May, April and June. In November, January and March, the immunoreactions for vimentin and α-tubulin strongly accumulate in a perinuclear region of Sertoli cells when developmental spermatids are not seen in the seminiferous tubules. These accumulations in the immunoreactions for vimentin and α-tubulin seem to be caused by the reduction in size of Sertoli cells cytoplasm with season. However, the seasonal changes of distributions in the cytoskeletal proteins are obscure in the bear testes. These results suggest that the contents of cytoskeletal proteins may not change in relation to the morphological differences with season in the testes of the seasonal breeders.     

Characterization of the swimming muscle of the anchovy Engraulis anchoita (Hubbs and Martini 1935)

The lateral muscle characteristics of individual female anchovies (Engraulis anchoita) were studied by histochemical and ultrastructural techniques. Red, pink and white fibres were discerned on the basis of the activity of the metabolic enzymes succinic dehydrogenase, phosphorylase and myofibrilar ATPase, and the usage of Sudan and periodic-acid Schiff staining techniques. Red fibres were located at the surface, white fibres deep inside and pink fibres in between. The red fibres appeared flattened or ribbon-shaped in transverse section and they were located in rows separated by myosepta of connective tissue. The red and pink fibres were multi-innervated whereas the white fibres were terminally innervated. The relative proportion of the red muscle increased toward the caudal region, the white muscle diminished toward that region, whereas the proportion of pink muscle did not vary according to region, being scarce throughout. The distribution of capillaries was also investigated, and as a result, the vascular supply proved to be scarce in both white and pink muscle.     

Muscular architecture in the omasal laminae of cattle and sheep

The muscular architecture of the bovine omasal laminae was examined. The omasal laminae had three thin smooth muscle layers which consisted of an intermediate layer and two lateral layers. The muscle bundles of the intermediate layers ran radially in the laminae and those of the two lateral layers ran parallel to the free border of the laminae. At the free border, three types of the muscular architecture were observed. In a histological study, the muscle bundles of the intermediate layer penetrated into the connective tissue around the smooth muscle fasciculi of the inner layer of the tunica muscularis of the omasal wall and attached to the bundles of both the inner layer and of the outer layer of the tunica muscularis. These results indicate that a re-evaluation of the muscular architecture in the omasal laminae is required to facilitate better understanding of the omasal morphology and physiology.     

Intestinal smooth muscle cells locally enhance stem cell factor (SCF) production against gastrointestinal nematode infections

Smooth muscle cells can produce stem cell factor (SCF) in the normal state for the preservation of mast cells, but it is still unknown whether smooth muscle cells can enhance SCF production in response to the pathological stimuli. The present study showed that smooth muscle cells in mast cell-increased regions around worm cysts of intestinal nematodes significantly enhanced SCF gene expression compared with mast cell non-increased regions in same sample. SCF gene expression in mast cell non-increased regions in nematode-infected mice showed almost the same level as in non-infected control groups. These results indicate that smooth muscle cells can locally enhance SCF gene expression, and may have a role in local immunological reactions as growth factor-producing cells.