Ontogeny of fetal movements in the guinea pig

Assessment of fetal motility is an approach to evaluate the development and function of the nervous system before birth. Reference values for the time of first occurrence and the incidence of normal fetal movements are indispensable for studies in which prenatal motor activity is applied as a model to study the central and peripheral nervous systems. Studies on fetal motility have been performed in a few species, particularly in the human. The aim of the present study is to describe the ontogeny of fetal motility in the guinea pig, a precocious polytocous species.After a pilot study to establish procedures for repeated ultasonographic scanning of guinea pigs, 10 domesticated animals were scanned (5.0 or 7.5 MHz convex transducer) at 2-4 day intervals between day 24 and 63 of gestation (term age 68 days). Per animal two selected fetuses were each scanned for 15 min. Images were stored on videotape and analyzed off-line for the first onset, presence and quality of fetal movement patterns, and quantity of sideway bendings, general movements, breathing movements and periods of fetal rest.Twenty-five different movement patterns could be characterized, 6 emerging at the onset of motor activity were performed only temporarily. The very first fetal movement was observed on day 24 gestational age, and subsequently most other movements developed during a period of only 5 days. Interfetal difference in onset of the frequently occurring sideway bendings, general movements, and front and hind limb movements was only 2 days. Sideway bendings and general movements co-existed during days 29 to 43. There were developmental trends in the course of pregnancy. Sideway bendings increased rapidly between 24 and 30 days and declined hereafter. General movements and fetal breathing increased during midpregnancy and declined towards parturition. Conversely, fetal rest was observed for approximately 60% of time at midgestation and a marked increase was found towards parturition. There were no significant differences in developmental trend of the various movement patterns between individual fetuses.Fetal motility in the guinea pig followed a specific temporal pattern, like in the human, but at a different time scale. The present quantitative data will enable functional investigations into the role of the neuromuscular system. They may also facilitate studies on the effect of environmental influences, such as stress, drugs, toxic substances, and food conditions, on fetal neurobehavioural development in this species.     

Effects of pontomedullary reticular formation stimulation on the neuronal networks responsible for rhythmical jaw movements in the guinea pig

1. In the ketamine-anesthetized guinea pig, electromyographic (EMG) responses of the digastric muscle and vertical and horizontal movements of the mandible were studied when loci within the caudal pontine and rostral medullary reticular formation were stimulated during rhythmic jaw movements (RJMs) evoked by stimulation of the masticatory area of the cortex. 2. Within these regions electrical brain stem stimulation of the pontis nucleus caudalis and nucleus gigantocellularis (PnC-Gi) of the reticular formation completely blocked RJMs at stimulus intensities as low as 10 microA while suppressing the short-latency digastric EMG response that was time locked to each cortical stimulus in the train. PnC-Gi stimulation did not, however, reduce the excitability of the short-latency corticotrigeminal excitatory pathway to digastric motoneurons when tested by short pulse train stimulation at 2 Hz (3 pulses, 500 Hz, 0.3 ms) in the absence of RJMs. 3. Short trains (80 ms) of PnC-Gi stimuli delivered at various phases of the RJM cycle produced a permanent phase shift of the RJM rhythm. If the stimulus train was delivered at an early phase of the cycle (8-40%) the next cycle onset was advanced; if the train was delivered later in the cycle (60-80%) the next cycle onset was delayed. Long trains of PnC-Gi stimuli (100, 200, 300, and 400 ms) increased the time of onset of the next cycle by an amount directly proportional to the duration of the stimulus train. 4. Digastric EMG activity occurring during cortically evoked RJMs occupied nearly 50% of the cycle. If a short train of PnC-Gi stimuli was delivered between approximately 5 and 125 ms after the onset of the burst, the duration of the burst was significantly shortened. 5. These results demonstrate that the suppression of cortically evoked RJMs resulting from PnC-Gi stimulation is due to direct effects on central circuits responsible for the production of the RJM behavior and not on the motoneurons themselves. The evidence presented is consistent with our previously presented hypothesis that the neurons involved in mediating the short-latency corticotrigeminal pathway to digastric motoneurons are separate and distinct from those neurons comprising the central networks responsible for the production of the fundamental jaw oscillation during RJMs.     

面神经骨管对失神经支配面神经损伤的影响

目的探讨实验性面瘫面神经骨管对面神经乃至运动终板损伤及开放面神经骨管的意义。方法压榨面神经制作颞骨内绞扼性面瘫实验模型,分为开放面神经骨管组(开放组)和非开放面神经骨管组(非开放组),非实验侧作为正常对照组。分别测定两组面神经膨胀率。应用诱发肌电图仪分别测试两组压榨前后的刺激反应阈值。应用透射电子显微镜观察两组面神经的病理变化。应用"盐酸消化法"制作口轮匝肌的扫描电子显微镜标本,观察次级突触间隙的变化。结果开放组膨胀率平均为42.6%±6.3%,非开放组膨胀率平均为38.1%±2.8%,两组间差异显著(t=5.41,P<0.01)。开放组面神经髓鞘和轴突变性明显比非开放组轻,开放组次级突触间隙隙沟明显多于非开放组。开放组反应阈值恢复到压榨前,平均需32.8±6.4d,而非开放组平均需57.3±9.5d,两组间差异显著(t=6.01,P<0.01)。结论面神经骨管对病变面神经有绞扼性损伤作用,开放面神经骨管能解除骨管对面神经的绞扼性损伤作用,有利于面神经及运动终板功能恢复,提示临床颞骨外伤性面瘫行面神经减压术有利于面神经功能的恢复。     

The permeability of blood vessels in the guinea pig cochlea

Summary Horseradish peroxidase (HRP) has been injected intravenously in order to study its transport across endothelia of modiolar blood vessels. Fixation was performed by vascular perfusion at timed intervals after injection of the trace (1/2, 1, 2, 3, 5, 8, 10, 15, 20, 25, 30, 45 and 60 min).Fenestrated capillaries are found in the cochlear plexus only. In this region, diffusion of HRP into extracapillary spaces occurs already 1/2 min after the injection. It is possible to demonstrate the outflow of HRP across endothelial fenestrae.Vesicular transport of HRP across nonfenestrated endothelia (capillaries of the spiral ganglion, cochlear nerve, spiral limbus and the spiral vessel) does not reach significant amounts in the time intervals studied. Although HRP is found in membrane bound endothelial vesicles already 1 min after its injection, its concentration in extravasal spaces never attains amounts necessary for its histochemical demonstration. Thus these endothelia represent a blood-perilymph barrier to HRP.Director: Prof. Dr. Dr. F. WustrowDirectors: Prof. Dr. R. Ortmann, Prof. Dr. B. KummerPresented in part at the 10th Colloquium on Inner Ear Biology, Graz, 12th September 1973.This work was supported by a grant of the Deutsche Forschungsgemeinschaft, project receptor physiology.     

Studies on the haemotoxicity of chloramphenicol succinate in the Dunkin Hartley guinea pig

In man, chloramphenicol (CAP), induces two major haemotoxic effects. First, a reversible, dose-related reticulocytopenia and anaemia developing during treatment. Second, a non-dose-related aplastic anaemia (AA), developing weeks after treatment, is often irreversible and fatal. In previous studies, we developed a mouse model of the reversible reticulocytopenia/anaemia using CAP succinate (CAPS); attempts to induce AA in the mouse with CAPS were unsuccessful; in the rat, CAPS induced only minimal haemotoxicity. We therefore wished to investigate haematological changes caused by CAPS in a third rodent, particularly in relation to the induction of significant 'late stage' bone marrow depression (AA). Female guinea pigs were gavaged with CAPS in three experiments. In a dose ranging study, CAPS (at 2500 and 3500 mg/kg) was administered daily for 9 days, and blood examined at 1 day post dosing. CAPS induced increased erythrocyte values (an apparent haemoconcentration effect), and reduced reticulocytes and femoral marrow nucleated cell counts (FNCC). In a second experiment, CAPS was given at 333, 666 and 1000 mg/kg (13 days); haematological changes were compared with results from the initial study, with evidence of dose-related effects. In a final experiment, CAPS was administered (825 mg/kg, 16 days) and blood studied at 1, 12, 28 and 63 days post dosing. At day 1, erythrocyte values were decreased (NS), and reticulocytes and FNCC were reduced; the marrow was hypocellular with erythroid depletion. At 12 and 28 days, values returned towards the normal range. At 63 days, parameters were normal. Thus, CAPS (825 mg/kg for 16 days) induced changes comparable to the reversible bone marrow depression seen in man; but there was no evidence of 'late stage' (i.e. at 63 days) marrow depression, as would be seen in a developing or overt marrow aplasia (AA). The guinea pig (like the mouse) is a model for the early events, but is not a good model for CAP-induced AA in man.     

顺铂、速尿对豚鼠内耳损害的形态学观察

本文观察了豚鼠静脉注射顺铂、速尿及两药伍用后内耳血管纹、毛细胞微细结构的改变。结果表明;速尿仅对血管纹有损伤作用,而顺铂不仅对毛细胞而且对血管纹均有损伤作用。两药伍用后增加了这两个部位的损伤作用。并对超微结构进行了详细的描述。     

Differential involvement of two cortical masticatory areas in modulation of the swallowing reflex in rats

To clarify the functional role of cortical descending inputs involved in the swallowing reflex, the effect of electrical stimulation of two cortical masticatory areas (CMAs: A- and P-area) on rhythmic jaw movements (RJMs) and superior laryngeal nerve (SLN)-evoked swallows were studied. RJMs and swallowing reflex were elicited by repetitive electrical stimulation of CMAs and the SLN, respectively. The electromyographic activities of jaw-closer (masseter), jaw-opener (digastric), and laryngeal-elevator (thyrohyoid) muscles were recorded to identify the RJMs and swallowing reflex. The number of evoked swallows was significantly lower, and swallowing interval was significantly longer during A-area stimulation compared with those without stimulation. Conversely, these parameters were not significantly altered during P-area stimulation. The inhibition of swallows by A-area stimulation was not affected by an increase in sensory input by wooden stick application between upper and lower teeth, or A-area stimulation preceding SLN stimulation. The present findings suggest that the swallowing reflex is inhibited by activation of the A-area, but not the P-area. Since no changes in swallows were seen after the increase in intraoral sensory input and prior activation of masticatory central pattern generator (CPG), swallowing inhibition may be mediated by direct inputs from the A-area or inputs via the masticatory CPG into the swallowing CPG.     

Effect of L-lysine monohydrochloride on cutaneous herpes simplex virus in the guinea pig

The effect of topical applications of crystalline lysine therapy on cutaneous herpes simplex virus (HSV) inoculations and subsequent dorsal root ganglia (DRG) infection was studied in male Hartley guinea pigs. Although HSV-I was recovered from the inoculated sites from all animals, the L-lysine-treated skin remained clinically normal, whereas untreated controls manifested clinical symptoms up to 3 days postinoculation (p.i.). However, cocultivation of DRG (C1-S1) indicated a selective tropism of infective particles to specific DRG in the groups treated with amino acids. In lysine-treated animals, HSV was recovered from a few DRG (T-12, T-13, and L-1) at 3 days p.i. and from DRG T-10 in leucine-treated controls; yet no HSV was recovered from DRG of untreated controls. These results suggest an immunomodulatory effect of L-lysine on inoculation site infections and the possible potentiation of subsequent DRG manifestation in amino-acid-treated animals.     

Comparison of mandibular movement trajectories and associated patterns of oral muscle electromyographic activity during spontaneous and apomorphine-induced rhythmic jaw movements in the guinea pig

Vertical and horizontal movements of the lower jaw (mandible) of ketamine-anesthetized guinea pigs were recorded in association with electromyographic (EMG) activity in the anterior digastric, lateral pterygoid, medial pterygoid, and deep masseter muscles during spontaneously occurring rhythmic jaw movements (SRJMs) and during rhythmical jaw movements induced by the intravenous administration of apomorphine (ARJMs). Both ARJMs and SRJMs were near periodic and occurred at frequencies in the 2- to 5-Hz range. However, the profiles of the mandibular movements and associated patterns of jaw muscle EMG activity differed dramatically for SRJMs versus ARJMs. SRJMs were characterized by prominent lateral excursions of the mandible that occurred in association with both the jaw opening and closing movements. The lateral excursions were directed to the left side on some SRJM cycles and to the right side on others. The direction of the lateral component alternated irregularly, but no more than three consecutive cycles with horizontal movements to the same side were observed at any time. Each SRJM cycle was generated by the occurrence of one of two coordinated sequences of EMG activity. One sequence produced right-sided cycles, the other produced left-sided cycles. Each sequence was initiated by an EMG burst in the digastric muscle ipsilateral to the direction of the horizontal excursion of the mandible, followed by EMG bursts in the contralateral digastric, lateral pterygoid, and medial pterygoid muscles. The EMG bursts in the digastrics and contralateral lateral pterygoid muscles were associated with jaw opening and the initial stage of lateral movement. EMG activity in the contralateral medial pterygoid muscle was associated with the onset of closing and a second stage of lateral movement. Masseter muscle activity was also observed during SRJMs, but only in a subset of the animals tested (3 of 12). When present, the masseter activity began well after the onset of jaw closing. No significant horizontal mandibular movements were observed during ARJMs. The mandibular trajectories during opening and closing always remained close to the midline. The opening phase of ARJM cycles was associated with bilaterally synchronized activity in the digastric and lateral pterygoid muscles. The closing phase was associated with bilaterally symmetric activity in the masseter muscles. The medial pterygoid muscles displayed little or no EMG activity during ARJMs. The durations of the EMG bursts recorded in the masseter muscle were correlated with cycle time during SRJMs, as were the burst durations of the digastric and lateral pterygoid muscles during ARJMs.(ABSTRACT TRUNCATED AT 400 WORDS)     

Action of finoptin on cAMP dynamics in the isolated guinea pig heart during contraction and relaxation

Research Institute of Cardiology, Tomsk Scientific Center, Academy of Medical Sciences of the USSR. (Presented by Academician of the Academy of Medical Sciences of the USSR R. S. Karpov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 11, pp. 455–457, November, 1990.     

The subcomponent C1q of the first component of guinea pig complement: Purification and characterization

Guinea pig C1q was purified, in a highly active hemolytic form, by a combination of precipitation with chelating agents, CM-cellulose and Sepharose 6B. Yields ranged from 30 to 35% protein, and the activity of final preparations was in the range of 2 × 10¹³– 3 × 10¹³ C1q effective molecules/mg. The molecular weight of C1q was approximately 430,000, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS). C1q was shown to be composed of two non-covalently linked subunits of approximate molecular weights 46,500 and 45,000 in a molar ratio 2 : 1. On reduction, the higher molecular weight subunit gave two chains having approximate molecular weights of 24,500 and 23,000 in equimolar ratio, and the lower weight subunit gave one chain with a molecular weight of approximately 22,300. C1q contained hydroxyproline, hydroxylysine and a high percentage of glycine. Thus, the overall molecular structure of guinea pig C1q appears similar to that of human C1q.The antiserum against the purified C1q showed only one precipitation band with guinea pig whole serum of purified C1q on immunodiffusion analyses and was found to be monospecific.     

Identification of motoneurons supplying the tensor veli palatini muscle in the guinea pig and cat: An horseradish peroxidase study

Identification of motoneurons supplying the tensor veli palatini muscle was attempted by the horseradish peroxidase (HRP) method in the guinea pig and cat. After HRP injection into the tensor veli palatini muscle, HRP-labeled neurons were seen in the regions closely medial to the cluster of the lateral pterygoid motoneurons in the dorsolateral division of the trigeminal motor nucleus. In the guinea pig the tensor veli palatini motoneurons were observed at the level of the whole rostrocaudal extent of the trigeminal motor nucleus, while in the cat they were seen at the level of the rostral two-thirds of the nucleus.     

Inhibitory effect of aerosol WP871 on SRS-A mediated bronchoconstriction in the guinea pig in vivo

Slow-reacting substance of anaphylaxis (SRS-A) is an important factor mediating bronchoconstriction in asthma. We developed a guinea pig model for SRS-A mediated bronchoconstriction induced by antigen inhalation. Using this model, we investigated the effect of inhaled WP871, a new anti-allergic drug, on bronchoconstriction. Aerosol WP871 (0.01 and 0.033%) to some extent inhibited the antigen-induced bronchoconstriction in a dose-dependent fashion, but high-dose WP871 (0.1%) inhalation itself produced a non-specific bronchoconstriction. However, aerosol WP871 (0.033%) showed no inhibitory effect on bronchoconstriction caused by direct inhalation of leukotriene C4, a component of SRS-A. These findings indicate that aerosol WP871 does not antagonize SRS-A, but inhibits synthesis and/or release of SRS-A and has some non-specific bronchoconstrictive effect in high concentration.     

树、大鼠、豚鼠视交叉上核加压素免疫阳性神经元分布的差异性比较

目的 :观察加压素免疫阳性 (VP IR)神经元在树下丘脑视交叉上核中的分布并与其在大鼠豚鼠视交叉上核中的分布进行比较 ,探讨VP IR神经元分布的种属差异性。方法 :树、大鼠、豚鼠内固定后恒冷箱冰冻连续切片 ,免疫组织化学PAP法染色。结果 :三种动物的视交叉上核形状不同 ,VP IR神经元在三种动物视交叉上核中的分布位置、数量和密度不同 ,此外 ,在豚鼠两侧视交叉上核间以及第三脑室底部与视交叉正中背侧之间 ,还观察到一些散在分布的VP IR神经元 ,而树和大鼠相应区域却未见有VP IR神经元分布。结论 :VP IR神经元在视交叉上核中的分布有较大的种属差异性     

失面神经支配后豚鼠口轮匝肌线粒体和琥珀酸脱氢酶活性变化

目的探讨不同程度面神经失神经支配对口轮匝肌及线粒体琥珀酸脱氢酶(SDH)活性的影响。方法制造颞骨外面神经麻痹豚鼠模型,在压榨程度相同条件下分为面神经压榨15S组、30S组,再分为观察7d组、30d组。SDH染色后,应用计算机图像分析系统进行各组纤维SDH酶含量测定,并观察线粒体结构和SDH酶阳性反应产物的变化。并应用瞬目反射方法测试15S组、30S组瞬目反射恢复时间。结果15S7d组I型和Ⅱ型SDH酶呈色反应较正常组明显减弱(P0.01),30S7d组比15S7d组SDH酶活性显着性减弱(P0.01)。15S7d组线粒体嵴少量断裂,SDH酶阳性反应颗粒轻度减少;15S30d组基本恢复正常。30S7d组线粒体嵴多量嵴断裂,SDH酶阳性反应颗粒重度减少;30d组线粒体结构和SDH酶反应颗粒轻度恢复。瞬目反射15S组恢复正常需要(36±12)d;30S组半年内未见恢复到正常。结论面神经受损伤持续时间越长,失神经支配程度越重,肌纤维及线粒体病变越重,肌功能恢复越慢,建议应早期行面神经减压术。     

Compliance in the neck structures of the guinea pig spermatozoon, as indicated by rapid freezing and electron microscopy

Electron microscopy has been used to investigate whether the transversely striated columns of the connecting piece in the neck region of guinea pig spermatozoa, undergo lengthening and shortening as a result of the forces generated during motility. Motile spermatozoa were subjected to near-instantaneous rapid freezing, followed by freeze-substitution fixation and epoxy embedment. Thin sections passing longitudinally through the striated columns revealed that the periodicity was indeed variable. The repeat period, taken to have an unstressed width of 60 nm, could be found extended to 75 nm in some specimens, and reduced to 54 nm in others. The estimates of the coefficients of variation were 6.6% for the width of the 'dense' band and 33.5% for the 'pale' band. The 'pale' band in the extended state showed longitudinal striae. Such variations in length, which – it is suggested – are physiological, and passively induced, would have functional implications for the flagellum – for both bend initiation and bend growth. Also, hypothetically , any mechanism that could increase the degree of compliance in these columns, such as perhaps phosphorylation of the constituent proteins, could permit the flagellum to develop the exaggerated bend angles and asymmetries of the 'hyperactivated' state.     

Non-neuronal excitatory neurotensin receptors on the taenia coli of the guinea pig: lack of influence of tetrodotoxin and dynorphin

Picomoles of neurotensin caused contractions of the smooth muscles of the taenia coli and the myenteric plexus preparation of the guinea pig ileum. The musculotropic effect of neurotensin on the taenia coli was resistant to tetrodotoxin and to treatment with dynorphin. In contrast, the contractile activity of the neuropeptide in the ileum was substantially modified by pretreatment with tetrodotoxin or dynorphin. It is concluded that, whereas neurotensin causes a direct muscular response on the taenia coli via activation of selective peptide receptors probably located on the muscle membrane, the neuropeptide causes a predominant indirect action on the ileum mediated apparently via the release of acetylcholine from the nerve terminals of the myenteric plexus. Neurotensin may play a role in the control of gut peristalis either by modifying the release of neurotransmitters or by directly influencing the smooth muscles of the intestines.     

Distribution of NADPH-diaphorase and nitric oxide synthase-containing neurons in the intramural ganglia of guinea pig urinary bladder

The cell population and distribution of NADPH-diaphorase positive and NOS immunoreactive intramural ganglion cells were examined on stretched whole-mount preparations of the guinea pig urinary bladder which was divided into 3 regions: base, body and dome. The results showed that the highest frequency both of NADPH-d and NOS positive neurons was observed in the bladder base. Cell counts in the whole bladder showed that the number of NADPH-d positive neurons was much more than that of NOS immunoreactive neurons. Using neuron specific enolase (NSE) positive neurons as a reference (100%), NADPH-d positive neurons accounted for 84% while NOS immunoreactive neurons only made up 45% of the total neuronal population. These results, along with previous studies on the function of nitric oxide, suggest that nitric oxide may be involved in the relaxation activity in the bladder base during micturition. The significant difference in the number of NADPH-d positive and NOS immunoreactive neurons suggests that the localisation of one enzyme does not necessarily reflect the presence of the other.     

碱性成纤维细胞生长因子对谷氨酸毒性损伤豚鼠视网膜内突触小泡蛋白表达的影响

目的:探讨过量谷氨酸毒性损伤豚鼠视网膜内突触小泡蛋白(SYP)的表达及碱性成纤维细胞生长因子(bFGF)对其表达的影响。方法:豚鼠随机分成谷氨酸钠损伤组、对照组和bFGF治疗组。采用免疫组织化学方法和图像分析技术,对各组豚鼠视网膜内SYP免疫反应产物的表达进行检测。结果:对照组豚鼠视网膜内SYP的表达为强阳性,主要定位于外网状层和内网状层,损伤组视网膜相应区域内阳性反应产物的光密度值明显低于对照组,bFGF治疗后SYP的阳性表达明显高于损伤组,且与对照组相比,无显著性差异。结论:bFGF可抑制过量谷氨酸钠诱发的视网膜内SYP的表达减少,上调SYP的表达,对视神经损伤有显著地促功能修复作用。     

Some determinants of intake and patterns of feeding in the guinea pig

Regulation of food and water intake was studied in young and adult Guinea pigs by continuously monitoring ad lib feeding and drinking patterns and by examining the response to levels of celluflour dilution that ranged from 20–75%. Meal size and the duration of the intermeal interval were not systematically related to the sizes of preceding meals or interval lengths. Variations in food intake were mediated almost entirely by changes in meal size. This parameter increased during growth, was elevated in the first meal following food deprivation, decreased when water was withheld and increased when water was returned. The probability of drinking within 20 min of eating was 0.80. Celluflour dilution led to a decrease in apparent caloric intake without a proportional decrease in body weight. Regulation of energy balance and meal to meal control of feeding in this monogastric, herbivorous rodent is discussed in relation to the Guinea pig's digestive physiology and ecological niche.