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1.
We investigated the effects of nonselective muscarinic antagonist (atropine) and of selective muscarinic subtype 1 (M1), 2 (M2), 3 (M3) antagonists (VU0255035, methoctramine, pFHHSiD, respectively) on the contractions evoked by electrical field stimulation (EFS) or by exogenous ACh in isolated horse bronchial muscle. Atropine completely inhibited neurogenic contractions in a concentration‐dependent fashion, whereas selective muscarinic antagonists induced relevant modifications only at the highest concentration tested. Experiments with selective muscarinic antagonists in combination showed that only the simultaneous blockade of M1/M3 or M2/M3 receptors was able to induce a nearly complete suppression of contractions. The contractions induced by exogenous ACh were competitively antagonized only by atropine (pA2 = 9.01 ± 0.05). M3 selective antagonist, up to 10−6 m , caused a moderate concentration‐dependent rightward shift of ACh curve (pA2 = 7.96 ± 0.10). These data show that M3 muscarinic receptors possess a central role in mediating cholinergic contraction of horse bronchi, while M1 and M2 receptors seem to have a cooperative role. Selective muscarinic antagonists seem unlikely to be useful against bronchoconstriction associated with airway diseases in horses. Conversely, compounds with selectivity for both M1 and M3 receptors could be as effective as traditional anticholinergics and induce fewer cardiac side effects.  相似文献   

2.
Muscarinic receptors are considered to be of comparable clinical importance in chronic obstructive pulmonary disease (COPD) in equines and in humans. At present, data are scarce on the expression and distribution of probable subtypes of these receptors and their signalling pathways in airway segments, including lung parenchyma and bronchial and tracheal epithelium with the underlying smooth muscle in horses. Specific [N-methyl-3H]scopolamine chloride ([3H]NMS) binding to all three tissues was saturable and of high affinity, with K D values ranging between 1.6±0.7 and 1.9±0.3 nmol/L. [3H]NMS binding identified a higher density of total muscarinic receptors (fmol/mg protein) in the trachea (720±59 nmol/L) than in bronchi (438±48 nmol/L) or lung (22 ± 3 nmol/L). Competitive binding studies using [3H]NMS and the unlabelled subtype-selective antagonists pirenzepine and telenzepine (M1), methoctramine and himbacine (M2), 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) (M3), tropicamide (M4) and mamba toxin (MT-3) (M4) indicated the presence of at least three muscarinic receptor subtypes in peripheral lung tissue (50:40:24–28%: M2>M3>M1), whereas in bronchus and trachea M2 subtypes (87–90%) predominated over M3 (14–22%), and M1 subtypes were lacking. No differences were found between tissues in high-affinity binding sites for carbachol in the absence (31–36%) or presence of guanosine 5′-triphosphate (GTP) (∼100%). Western blotting for G-protein α-subunits showed a much more robust expression of Gαi1/2 in the trachea (with highest receptor density) than in the lung or bronchi, whereas Gαs-protein was dominantly expressed in bronchus. Concomitantly, carbachol inhibited isoproterenol- and GTP-stimulated adenylyl cyclase activity with increasing muscarinic receptor expression (trachea > bronchi > lung). We conclude that the expression and signalling pathways of muscarinic receptors in the equine respiratory tract are segment-dependent. These receptors might contribute to the pathogenesis of COPD in the horse and could provide potential drug targets for the therapeutic use of anticholinergics in this species.  相似文献   

3.
In coronary arterial rings isolated from horses, 10--8-10-6 mol/l acetylcholine (ACh) induced concentration-dependent contractions which were potentiated by the removal of endothelium and by pretreatment with I,-nitro-arginine (LNAG) or methylene blue (MB). Relatively lower concentrations of Ach 10-14-10-8 mol/l) induced relaxation when the coronary rings were contracted by phenylephrine (PE). ACh-induced contractions in the coronary rings without endothelium were competitively inhibited by each muscarinic subtype selective antagonist in the following order of potency: 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) > pirenzepine ≥ parafluoro-hexahydrosiladiphenidol (pFHHSiD) > methoctramine. ACh-induced relaxation in the rings with endothelium was inhibited by LNAG or MB, and by each selective antagonist in the following order of potency: 4-DAMP < pFHHSiD ≥ pirenzepine ≥ methoctramine. These results suggest that the ACh-induced contraction and relaxation in equine coronary arteries are mediated mainly by an M3-receptor located on the smooth muscle cells and endothelial cells, respectively, and that the stimulation of the M3-receptor on the endothelial cells liberates nitric oxide.  相似文献   

4.
The distribution of muscarinic receptors in equine airways was investigated using autoradiography. Frozen sections of tissue from six different levels in the bronchial tree, from the trachea to the distal bronchioles, were incubated in vitro with 1.5 nmol/L of the muscarinic receptor antagonist 1-[N-methyl-3H]scopolamine methyl chloride (3H-NMS). In addition, the subtype pattern of muscarinic receptors was investigated in equine tracheal smooth muscle using radioligand binding with methoctramine, tripinamide, 4-DAMP-methiodide and pirenzipine as competitors against the binding of 1.3 nmol/L 3H-NMS. The autoradiograms showed specific labelling indicating a high density of muscarinic receptors in smooth-muscle tissue in all levels of the airway tree investigated. Besides muscle tissue, subepithelial glands were the only structures specifically labelled. The dominating subtypes in tracheal smooth muscle investigated with radioligand binding studies were found to be M2 and M4, as both methoctramine (pK d = 8.5) and tripinamide (pK d = 8.6 and 6.7 for two different sites) showed high affinity. The density of the M3-muscarinic receptor subtype was low, but this subtype could be detected with statistical significance when methoctramine was used as the competitor against 3H-NMS binding.  相似文献   

5.
The responses of the vasculature of isolated, non-sensitized, bovine external ears to histamine and serotonin (5-HT) were evaluated while they were being perfused with Krebs-Henseleit solution, Histamine (10–5 mol/L to 5×10–3 mol/L) and 5-hydroxytryptamine (5-HT) (10–9 mol/L to 10–2 mol/L) caused increased vascular resistance. Mepyramine (10–7 mol/L), cimetidine (10–5 mol/L) and atropine (10–6 mol/L) inhibited the responses to histamine. The responses to 5-HT were inhibited by methysergide (10–9 mol/L) and potentiated by morphine (10–5 mol/L). These results suggest the presence of H1 and H2 histamine, and 5-HT receptors in bovine auricular vessels, all of which cause net vasoconstriction.  相似文献   

6.
The total muscarinic (M1 + M2 + M3) and -adrenergic receptors in the tracheal smooth muscle of conventional and double-muscled calves were identified and characterized with the non-specific antagonists [3H]quinuclidinyl benzilate ([3H]QNB) and [3H]dihydroalprenolol ([3H]DHA) respectively.Although the quantity of -adrenoceptors in double-muscled calves was 25% lower (p<0.05) than in conventional calves (B max=327±89 fmol/mg protein), adenylate cyclase assays indicated that the basal adenylate cyclase activity and the (–)-isopropylnoradrenaline (ISO)- and sodium fluoride (NaF)-stimulated values were not significantly different between these calves. However, the density of muscarinic receptors in double-muscled calves was 40% higher (p<0.01) than in conventional calves (B max=2955±625 fmol/mg protein). Subtypes of muscarinic receptors were studied with [3H]telenzepine (M1-receptors), [3H]AF-DX 384 (M2-receptors) and [3H]4DAMP (M1 and M3-receptors). It was found that in both double-muscled and conventional calves about 40% of the receptors were of the M3-subtype, the remaining 60% being M2-receptors.From these results, it is suggested that inflammation of the respiratory tract in double-muscled calves may be complicated by an imbalance between the cholinergic bronchoconstrictor and the -adrenergic bronchodilator components of the autonomic nervous system.  相似文献   

7.
The vasomotor effects of 5-hydroxytryptamine (5-HT) on isolated equine basilar arteries were studied. 5-HT induced contractions of equine basilar arteries in a concentration-dependent manner, with a pEC50 value (with 95% confidence limits) of 7.35 (7.08–7.62). Similar results were obtained with endothelium-denuded basilar arteries. Contractions were not competitively inhibited by the 5-HT2 receptor antagonist ketanserin at low concentrations of 5-HT. Conversely, at high concentrations of 5-HT, contractions were inhibited by ketanserin in a concentration-dependent manner, with a pA 2 value of 8.91 (8.62–9.20). The 5-HT1 and 5-HT2 receptor antagonist methiothepin shifted the concentration-response curve of 5-HT downwards and to the right in a concentration-dependent manner. In the presence of 10-6 mol/L ketanserin, however, methiothepin antagonized 5-HT-induced contractions competitively with a pA 2 value of 7.95 (7.59–8.31). The 5-HT3 receptor antagonist MDL 72222 had no effect on 5-HT-induced contractions. The findings of this study indicate that 5-HT1 and 5-HT2 receptors are located in equine basilar arterial smooth muscle cells, and that stimulation of these receptors results in contraction.Abbreviations CR concentration ratio - EC50 concentration producing 50% of the maximal response - 5-HT 5-hydroxytryptamine - MDL 72222 1H,3,5H-tropan-3-yl-3,5-dichlorobenzoate - pA 2 negative logarithm of the molar concentration of antagonist that produces a 2-fold rightward shift of the concentration-response curve - pEC50 negative logarithm of EC50 - PGF2 prostaglandin F2  相似文献   

8.

Background

This study was conducted to investigate effect of exogenous melatonin on the development of mouse mature oocytes after cryopreservation.

Results

First, mouse metaphase II (MII) oocytes were vitrified in the open-pulled straws (OPS). After warming, they were cultured for 1 h in M2 medium containing melatonin at different concentrations (0, 10−9, 10−7, 10−5, 10−3 mol/L). Then the oocytes were used to detect reactive oxygen species (ROS) and glutathione (GSH) levels (fluorescence microscopy), and the developmental potential after parthenogenetic activation. The experimental results showed that the ROS level and cleavage rate in 10−3 mol/L melatonin group was significantly lower than that in melatonin-free group (control). The GSH levels and blastocyst rates in all melatonin-treated groups were similar to that in control. Based on the above results, we detected the expression of gene Hsp90aa1, Hsf1, Hspa1b, Nrf2 and Bcl-x1 with qRT-PCR in oocytes treated with 10−7, or 10−3 mol/L melatonin and untreated control. After warming and culture for 1 h, the oocytes showed higher Hsp90aa1 expression in 10−7 mol/L melatonin-treated group than in the control (P < 0.05); the Hsf1, Hsp90aa1 and Bcl-x1 expression were significantly decreased in 10−3 mol/L melatonin-treated group when compared to the control. Based on the above results and previous research, we detected the development of vitrified-warmed oocytes treated with either 10−7 or 0 mol/L melatonin by in vitro fertilization. No difference was observed between them.

Conclusions

Our results indicate that the supplementation of melatonin (10−9 to 10−3 mol/L) in culture medium and incubation for 1 h did not improve the subsequent developmental potential of vitrified-warmed mouse MII oocytes, even if there were alteration in gene expression.  相似文献   

9.
Canine cognitive dysfunction syndrome (CDS) is a neurodegenerative disorder of aged dogs characterized by a progressive decline in cognitive function. In humans and laboratory animals, a variety of neurotransmitter abnormalities have been described in patients affected by age-related dementia. Specifically, the regulatory role of the catecholaminergic, serotonergic, and cholinergic systems has been outlined. The aim of the present study was to measure blood monoamine levels, platelet α2-adrenergic receptors, and lymphocyte muscarinic receptors in healthy adult and aged dogs and in dogs affected by canine cognitive dysfunction. Based on clinical and behavioral examination, 40 dogs were divided into 3 groups: healthy adults (n = 14), aged dogs (n = 17), and aged dogs affected by canine cognitive dysfunction (n = 9). A significant reduction in plasma levels of norepinephrine and dopamine was observed both in aged dogs (0.16 ± 0.02 ng/mL, P < 0.01; 0.11 ± 02 ng/mL, P < 0.01, respectively) and in CDS dogs (0.14 ± 0.03 ng/mL, P < 0.05; 0.10 ± 00.005 ng/mL, P < 0.01, respectively) compared with adults (0.29 ± 0.04 ng/mL and 0.15 ± 0.02 ng/mL, respectively). No significant differences were observed among groups for α2-adrenergic receptor concentrations. Canine lymphocytes express 2 distinct classes of muscarinic receptors, characterized by high (HA) and low affinity (LA) for [3H]-N-methyl-scopolamine. A significant age-dependent decrease in HA muscarinic receptors was observed. However, no differences were found between aged dogs (87.65 ± 11.08 sites/cell × 102) and in CDS dogs (90.17 ± 6.75 sites/cell × 102 ) for HA muscarinic receptor concentrations. As far as LA muscarinic receptors are concerned, CDS dogs showed a significant increase (393.48 ± 63 sites/cell × 102; P < 0.05) with respect to healthy adult dogs (188.84 ± 16.50 sites/cell × 102). Our results suggest that the reduction in HA muscarinic receptor-binding sites could be representative of the physiological aging process, whereas the increase in lymphocyte LA muscarinic receptor levels could be related to the cognitive decline.  相似文献   

10.
The effect of bombesin and of substance P was investigated in smooth muscle strips of the chicken crop. Bombesin in picomolar concentration (0.1×10-12–5×10-12mol/l) caused a concentration-related contraction of the muscle strips. Substance P in nanomolar concentration (0.1×10-9–10×10-9mol/l) was effective in the same manner. Tetrodotoxin (2×10-7mol/l) did not influence the contraction responses to either bombesin or substance P. The excitatory effect of bombesin and of substance P did not follow activation of cholinergic receptors since their effect on the crop smooth muscle was not antagonized by atropine (10-4mol/l) or by hexamethonium (10-4mol/l). Strips stored for 24 hours in the Tyrode's solution at 4°C without a supply of oxygen maintained their full sensitivity to bombesin and to substance P. These results are consistent with a direct action of bombesin and substance P on the crop smooth muscle.  相似文献   

11.
Apoptosis is necessary for both initiation and control of spermatogenesis; however, an increase in apoptosis can lead to subfertility/infertility in stallions, causing substantial financial loss in the equine industry. The ability of stem cell factor (SCF), leukemia-inhibiting factor (LIF), granulocyte–macrophage colony-stimulating factor (GM-CSF), and estradiol (E2), alone or in combination, to prevent apoptosis of germ cells in short-term equine testicular cultures was examined. Testicular tissue was sectioned into approximately 2-mm cubes and placed in media-filled culture chambers. Concentrations of SCF (100 ng/mL), LIF (10 ng/mL), GM-CSF (5 ng/mL), and E2 (10−9 mol/l) were added alone or in combination to each well. After 6 hours in culture, the tissue was fixed and immunohistochemically (terminal deoxynucleotidyl transferase-mediated nick-end labeling; TUNEL) stained for apoptosis detection. Apoptotic cells per 100 Sertoli cell nuclei within seminiferous tubules were counted until the 500th Sertoli cell nuclei was reached. This counting procedure was used for each slide. An analysis of variance (ANOVA) with a Tukey's test was used to compare apoptotic rates. In comparison with the control, GM-CSF alone lowered apoptosis by 34.77%. GM-CSF–treated tissue combined with SCF and LIF as well as GM-CSF combined with SCF, LIF, and E2 reduced apoptosis when compared with the control (37.45% and 44.40%, respectively) or other treatment combinations. GM-CSF alone reduced apoptosis; results suggest possible synergy for the combinations of SCF and LIF with GM-CSF and for E2 with SCF, LIF, and GM-CSF.  相似文献   

12.
This study showed that chicken bronchus is relatively insensitive to histamine. H1 histamine receptors appear to mediate bronchoconstriction to histamine. In the presence of mepyramine, high doses of histamine (10–3 to 5×10–3M) produce weak bronchorelaxation which is susceptible to cimetidine.Cimetidine alone potentiated the bronchoconstriction to histamine. This shows the presence of a small population of histamine H2-receptors in chicken bronchus, which may modulate bronchospasm during pulmonary allergic reactions.  相似文献   

13.
Young adult sheep were dosed with extracts of Narthecium ossifragum plants by the oral or parenteral routes and the resulting nephrotoxicity was assessed from the increases in the concentrations of creatinine and urea in the serum. Following single intraruminal or intraperitoneal doses of extracts derived from 30 g N. ossifragum (wet weight) per kg live weight (kg lw), serum creatinine concentrations increased from about 100 mol/L to between 260 and 510 mol/L. The serum urea concentrations increased from about 5–8 mmol/L to between 11 and 66 mmol/L in individual sheep. Daily intraruminal administration of 5–30 g/kg lw to three sheep over a 10- or 15-day period increased creatinine concentrations from 100 mol/L to 300–760 mol/L, and urea concentrations from 5–8 mmol/L to 35 mmol/L. A single intraperitoneal challenge dose of 30 g/kg lw, delivered 7 or 12 days after the final intraruminal dose, did not lead to increased serum creatinine or urea concentrations, indicating that oral treatment had apparently resulted in an increased tolerance to the nephrotoxic principle(s) in N. ossifragum.  相似文献   

14.
The serotonergic regulation of feeding behaviour has not so far been studied in ruminants. Therefore, the effects of some serotonin (5-HT) receptor agonists and antagonists on food intake and forestomach motility were studied in dwarf goats.Goats ate less food when treated intravenously (IV) with the 5-HT precursor 5-HTP (25 µg, 50 µg or 100 µg kg–1 min–1 over 15 min) than when they were treated with 5-HT (which does not pass the blood-brain barrier) or with saline. Accordingly, IV dexfenfluramine infusions (50 µg or 100 µg kg–1 min–1 over 15 min), which induces release of brain 5-HT, also led to dose-related reductions in food intake. In contrast, no anorectic effects were observed after IV infusions with the selective 5-HT reuptake inhibitor fluoxetine (100 µg kg–1 min–1 over 15 min), the selective 5-HT1A agonist 8-OH-DPAT (0.5 µg kg–1 min–1 over 15 min), or eltoprazine (4 or 8 µg kg–1 min–1 over 15 min), a mixed 5-HT1A/5HT1B receptor agonist. None of the 5-HT antagonists tested gave any increase in food consumption in this model. Interestingly, the non-selective 5-HT receptor antagonist methysergide (360 µg/kg IV) reduced food intake. This effect was most noticeable at 3 h after injection. The 5-HT3 receptor antagonist ondansetron (IV 10 µg kg–1 min–1 over 15 min) and the peripheral 5-HT2 receptor antagonist xylamidine (IV 100 µg kg–1 min–1 over 10 min) failed to modify food intake. These results provide evidence for central serotonergic involvement in the control of feeding. However, this control system differs markedly in goats and rodents.Dexfenfluramine, 5-HTP and eltoprazine administered at similar dose rates to those used in the food intake experiments induced some clinical signs including inhibition of forestomach contractions. These results, together with our earlierin vivo andin vitro observations, suggest that the inhibitory effects of serotonin receptor agonists on forestomach contractions are due to interactions with both peripheral and central serotonergic receptors. The change in smooth muscle tension, which leads to a change in the signals transmitted via vagal afferents to the central nervous system, appears not to modify feeding behaviour in dwarf goats.  相似文献   

15.
Recent research suggests that the subcellular location and nuclear concentration of glucocorticoid receptors may have a significant impact on cell sensitivity to stimuli acting through cyclic AMP or protein kinase C second messengers. The present study was performed in order to determine whether there may be diurnal fluctuations in the cytosolic and/or nuclear glucocorticoid receptors in equine peripheral blood mononuclear cells (PBMC). Jugular blood samples were collected by venipuncture from four resting unconditioned horses. Samples were collected at 8 AM, 2 PM, 8 PM and 2 AM. The PBMC were harvested from Ficoll gradients. Cytosolic and nuclear fractions were recovered by centrifugation from homogenized PBMC. Protein concentrations of the resulting fractions was determined and serial dilutions incubated with 3H-cortisol in the presence or absence of excess unlabeled dexametha- sone. Saturable specific binding was linear for 75 to 200 µg of protein which was recovered from 10xl05 to 100xl06 equine PBMCs. This binding was eliminated in heat-treated samples. Further, specific binding of cortisol to cytosolic fractions was reduced (P<.05) at 8AM as compared to binding at 2 PM and 2 AM. Nuclear receptor binding was high during daylight hours and undetectable at 2 AM. Total cellular receptor was highest at 2 PM and lowest at 2 AM. Results from this experiment suggest that diurnal fluctuations in equine cortisol concentrations are related to changes in the subcdlular distribution ofglucocorticoid receptors in PBMCs. Changes in the total amount of receptor also suggests that there are diurnal changes in glucocorticoid receptor synthesis and/ or recycling. Thus, diurnal variations in glucocorticoid interactions with second messenger pathways may be of importance in the equine species.  相似文献   

16.
A survey on feeding practices was conducted with 60 farmers belonging to four categories (15 farmers in each): male farmers without off-farm income (M–), male farmers with off-farm income (M+), female farmers without off-farm income (W–), and female farmers with off-farm income (W+). Data on herd size, feeds offered, milk production, chest girth, reproduction and management were collected monthly over a period of 1 year. In addition, samples of fodder and concentrates were collected monthly and analysed for dry matter (DM), organic matter (OM), crude protein (CP) and in vitro organic matter digestibility (OMD). Of the 550 rations analysed, grass was included in 99.8% of all rations, followed by gliricidia (65%), creepers (50%) and jak leaves (32%). Consequently, the rations were high in OMD (47–59%) and CP (7.8–23.5%). High-protein forage or coconut cake or both were also included as a supplement in 92% of the rations. Both M– and W– farmers had larger (p<0.001) herds (mean 1.8 animal units (AU) per household) than their counterparts with off-farm income (mean 1.44 AU/household), but only the male farmers without off-farm income achieved higher feeding levels (84.4 vs 65.6–72.1 g digestible organic matter (DOM)/kg0.75 per day) and milk production (6.4 vs 5.3–5.7 L/lactating cow). The lower production of animals kept by female and M+ farmers was related to lower feeding levels. M– farmers realized higher feeding levels than their M+ counterparts. W– farmers did not collect extra feed in response to higher levels of production. It was concluded that dairy farming in the mid-country of Sri Lanka is particularly important for poorer households without income from off-farm employment.  相似文献   

17.
Bovine tuberculosis (bTB) is a continuing problem in British herds. Micro-nutrients are important for the maintenance of well-functioning immune system. The aim of this study was to determine whether the selenium, copper and vitamin B12 status of cattle was associated with Mycobacterium bovis (M. bovis) infection. Between 2002 and 2005, 200 cattle (43% dairy, mean age 4.6 years), reactors according to the standard interpretation of the tuberculin test, and 200 in-contacts (41% dairy, mean age 4.4 years) non-reactors, which had been in contact with cattle with bTB, were selected from herds in England and Wales. Levels of the seleno enzyme glutathione peroxidase (GSHPx), copper and vitamin B12 were measured in blood. Confirmation of bTB infection was made by bacteriological culture and histopathology following a detailed postmortem. Levels of selenium and copper were also measured in a random sample of 63 livers. bTB was confirmed by culture/histology in 23/200 (11.5%) of in-contacts and 110/200 (55%) of reactors. In blood drawn at recruitment, GSHPx was lower in cattle with confirmed bTB compared to other cattle (geometric means 59.7 u/mL versus 78.9 u/mL red blood cells (RBC), p < 0.01). Vitamin B12 was similar (geometric means 161.5 pmol/L versus 165.5 pmol/L, p = 0.62) and copper was similar (geometric means 14.4 μmol/L versus 14.1 μmol/L, p = 0.55). In logistic regression models including all micro-nutrients simultaneously and controlling for age, sex, animal production class, herd size, number of reactors, postmortem laboratory and seasonal trends, lower levels of GSHPx (adjusted OR 0.42, 95% CI 0.21–0.81 per 100 u/mL RBC, p = 0.01) and higher levels of copper (adjusted OR 1.69, 95% CI 1.21–2.36 per 5 μmol/L, p < 0.01) were associated with an increased risk of confirmed bTB but there was no association with vitamin B12. There was evidence for a stronger association between confirmed bTB and GSHPx in in-contacts (adjusted OR 0.21, 95% CI 0.06–0.79 per 100 u/mL RBC) compared to reactors (adjusted OR 0.50, 95% CI 0.21–1.23 per 100 u/mL RBC) (p = 0.08 for interaction). Lower liver copper was associated with a higher risk of confirmed bTB (adjusted OR 0.15, 95% CI 0.02–1.0 per 5000 μmol/kg dry mass, p = 0.05) but there was no association between liver selenium and bTB. Trace micro-nutrient status may affect susceptibility to M. bovis infection in cattle. Further studies are needed.  相似文献   

18.
A novel, simple method of infectious center assay was developed to detect and quantitate the intracellular existence of equine herpesvirus 1 and equine herpesvirus 2 in peripheral blood mononuclear cells infected in vivo and in vitro with the viruses by cocultivation of these cells with a permissive equine cell culture. The infectious center titers were correlated with the infectious virus titers. In vivo equine herpesvirus 1-infected mononuclear cells obtained from ponies experimentally infected with the virus and equine herpesvirus 2-infected mononuclear cells obtained from selected naturally infected ponies with the virus gave by infectious center assay a mean value of 67 infectious center/2 x 106 cells as a peak titer on day 4 postinfection and 26 infectious center/2 x 106 cells for equine herpesvirus 1 and equine herpesvirus 2 respectively. The mononuclear cells, in both cases, did not contain detectable infectious virus, but the infectious virus was detected from the respective cells when they were cultured in the presence of mitogen. The equine herpesvirus 1 infected mononuclear cells in culture gave a mean count of 8.05 x 102 infectious center/2 x 106 cells/mL and contained 1.08 x 104 plague assay/mL of infectious virus. Similarly the equine herpesvirus 2 infected mononuclear cells in culture gave a mean count of 7.1 x 101 infectious center/2 x 106 cells/mL and contained <101 tissue culture infective dose50/mL of infectious virus. Mononuclear cells infected in vitro with equine herpesvirus 1 gave a mean count of 9.3 x 104 infectious center/2 x 106 cells/mL and contained 5.75 x 103 plaque assay/mL of infectius virus. Culturing these cells in the presence of mitogen gave a mean count of 5.5 x 103 infectious center/2 x 106 cells/mL and contained 9 x 103 plague assay/mL of infectious virus. A correlation between infectious center assay and infectious virus assay is discussed.  相似文献   

19.
Muscarinic and -adrenoceptors were identified in airway epithelium, smooth muscle and lung parenchyma from Holstein-Friesian calves and cows and were characterized with [3H]quinuclidinyl benzilate and [3H]dihydroalprenolol, respectively. The muscarinic receptor density in the smooth muscle of cows (B max=4803±245 fmol/mg protein) was 33% greater (p<0.01) than in calves. Low receptor numbers were detected in the epithelium and parenchyma. In both calves and cows, the density of epithelial -adrenoceptors was twice as high as in smooth muscle and parenchyma. The quantity of -adrenoceptors in the tracheal epithelium (B max=994±83 fmol/mg protein) and smooth muscle (B max=492±41 fmol/mg protein) in cows was respectively 37% (p<0.001) and 35% (p<0.01) lower than in calves. Adenylate cyclase (AC) assays indicated that the basal and the (–)-isopropylnoradrenaline- (ISO-) stimulated cAMP production were not significantly different between the calves and cows. After stimulation with NaF, significantly higher cAMP production was found in all tissues from cows. Significant correlations were found between absolute AC responses to NaF and -adrenoceptor density in epithelium (r=–0.75,p<0.001) and smooth muscle (r=–0.63,p<0.01). It seems that, in older animals, the production of cAMP is independent of the number of receptors, indicating the presence of fully active compensatory mechanisms.Abbreviations AC adenylate cyclase - cAMP intra-cellular adenosine monophosphate - G-protein GTP binding protein - GTP guanosine 5-triphosphate - ISO isopropylnoradrenaline - M muscarine - QNB quinuclidinyl benzilate  相似文献   

20.
A study was performed to evaluate the use of precision-cut lung slices (PCLS) for studies on the contraction of equine airways. Lungs of 10 horses were taken to prepare PCLS of ˜250 μm from equine lung tissue using a special microtome. The lung slices were cultured and the enclosed small airways were monitored using a microscope with coupled digital camera, which was used to determine the airway luminal area and diameter from digital images. As indicated by the beating of the ciliated epithelium and reactivity of airways on methacholine challenge, the tissue slices were found to be viable for at least 24 h. The airways were not precontracted, as indicated by a missing dilatory effect of 1 mmol/L clenbuterol. Bronchoconstriction induced by both methacholine and histamine was found to be dose dependent. EC50 values based on luminal area were 1.12 μmol/L · /÷ 3.82 for methacholine and 0.68 μmol/L · /÷ 6.99 for histamine. In conclusion, the PCLS technique is promising for studies on small airways in the equine lung. In the present study the basic principles of in vitro (ex vivo) examinations with equine PCLS on airway reactivity were developed.  相似文献   

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