Transesophageal monitoring of aortic blood flow during nonemergent canine surgeries     

Piper L. Wall  DVM  PhD  DACVECC  ; Maisha M. Rudison  BS  ; Tatjana Lazic  DVM  Dean H. Reidesel  DVM  PhD 《Journal of Veterinary Emergency and Critical Care》2002,12(1):1-8

Objective: To establish baseline values for descending thoracic aortic blood flow parameters as determined with a transesophageal combined M‐mode and pulsed Doppler ultrasound‐based monitoring method. Design: Preliminary observational study. Setting: University small animal teaching hospital. Animals: The study population consisted of anesthetized canine patients undergoing nonemergent surgeries. Prospectively set criteria for inclusion were adequate body size for placement of the esophageal probe and a nonemergent reason for surgery. The criterion for exclusion was recent trauma. Interventions: Placement of the transesophageal probe. Measurements and main results: Data was collected during 15 surgeries. Data from three dogs was excluded from data analysis (two recently hit by motor vehicles, one recently having undergone a total hip replacement). Each parameter was stable across time within each individual dog. The ranges of the descending thoracic aortic parameters across the 12 nonemergent cases were as follows: blood flow, 0.038–0.085 L min^?1 kg^?1; blood flow per beat, 0.31–0.84 mL kg^?1; blood acceleration, 6–29 m s^2?1; blood peak velocity, 38–105 m s^?1; left ventricular ejection time interval 331–492 ms; and diameter, 0.30–0.93 mm kg^?1. Conclusions: The range of descending thoracic aortic blood flow parameters encountered in this small group of dogs during nonemergent surgeries was broad; however, each parameter was quite stable across time with little change occurring in any dog during monitoring.  相似文献   

Effect of moxonidine hydrochloride on left ventricular hypertrophy in spontaneously hypertensive rats     

ZHANG Peng-bo  NIU Xiao-lin  SUN Yu-ming  CHANG Dan  JINYao-feng 《园艺学报》2003,19(8):1089-1091

AIM:To investate the effect of domestric moxonidine hydrochloride on myocardium fibrosis and coronary artery microvascular structure in left ventricular hypertrophy of spontaneously hypertensive rats(SHR).METHODS:30 male SHR, aged 20 weeks, were divided into group Mox+SHR, Cap+SHR and SHR randomly (10 in each group). 10 age and sex-mached sprauge-dawley rats were designed as normal control(NC). At the end of 13 weeks, left ventricular wight/body weight ratio(LVW/BW), collagen volume fraction(CVF) and standardized perivascular collagen area(PVCA) as well as intramyocardial arterial average medial thickness (AMT) were determined.RESULTS:LVW/BW, CVF, PVCA and AMT in group Mox+SHR were lower significantly than that in group SHR, respectively.CONCLUSION:Long-term antihypertensive treatment with moxonidine hydrochloride reduces myocardium fibrosis and improves impaired coronary artery microvascular structure in left ventricular hypertrophy.  相似文献   

Effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells from rats exposed to chronic hypoxia     

ZHANG Yong-chang  NI Wang  ZHEN Guo-hua  ZHANG Zhen-xiang  XU Yong-jian 《园艺学报》2003,19(8):1012-1015

AIM: To investigate the effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells (PASMCs) from rats exposed to chronic hypoxia. METHODS: (1) Wistar rats were randomly divided into control group (group A) and chronic hypoxia group (group B). Then group B received hypoxia 8 hours per day for 4 consecutive weeks. (2) Single PASMC was obtained via acute enzyme separation method. (3) Conventional whole-cell patch clamp technique was used to record resting membrane potential (Em) and ion currents of voltage-gated potassium channel. The changes of ion currents of voltage-gated potassium channel before and after applying cGMP (1 mmol/L), an agonist of protein kinase G (PKG), and cGMP plus H-8 (1 mmol/L), an inhibitor of PKG were compared between two groups. RESULTS: The Em of group B were significantly lower than that of group A. The ion currents of voltage-gated potassium channel in group A and group B were all significantly inhibited by cGMP [control group: from (118.0±5.0) pA/pF to (89.9±16.5) pA/pF, n=6, P＜0.05;chronic hypoxia group: from (81.0±5.0) pA/pF to (56.8±9.1) pA/pF, n=6, P＜0.05]and these effects were reversed by H-8 [control group: from (119.2±10.3) pA/pF to (117.8±9.1) pA/pF, n=6, P＞0.05;chronic hypoxia group: from (96.8±6.2)　pA/pF to (98.0±2.2)　pA/pF, n=6, P＞0.05]. CONCLUSIONS: The currents of voltage-gated potassium channel was inhibited by chronic hypoxic. The inhibitory effect of cGMP on currents of voltage-gated potassium channel in PASMCs from both normal and chronic hypoxic rats may be probably through the phosphorylation of voltage-gated potassium channel.  相似文献   

Effects of hypoxia and hypercapnia on expression of soluble guanylate cyclase in rat pulmonary artery     

XIA Xiao-dong  XU Zheng-jie  WANG Qun-ji  ZHANG Hong-qin 《园艺学报》2003,19(9):1214-1216

AIM:To investigate the expression of soluble guanylate cyclase protein and its mRNA in rat pulmonary artery after exposure to hypoxia and hypercapnia.METHODS:Male Sprague-Dawley rats were randomly split into 4 group, which were hypoxic hypercapnic (HH 1 week, HH 2 weeks, HH 4 weeks) group and control group, to copy pulmonary hypertensive animal model. The expression of sGCα₁ and β₁ subunits protein of medial and small pulmonary artery was performed by immunohistochemistry with a polycolonal antibody. In situ hybridization was performed on the rat lung tissue using sGC oligonuclear probe to assay the expression of sGCα₁subunit mRNA.RESULTS:The sGCα₁ and β₁ subunits protein and sGCα₁ subunit mRNA were faint staining in the pulmonary small and medium artery in HH1 week, HH 2 weeks and HH 4 weeks groups compared with control group (all P＜0.01).CONCLUSION:sGC subunit mRNA and protein expression in pulmonary small and medium artery were decreased after exposure to hypoxia and hypercapnia, which took part in the development of the pulmonary hypertension.  相似文献   

Rat urotensin-II-induced main pulmonary artery contractions are mediated by MAPK     

CHEN Shao-xian  XUE Bi-cheng  GONG Yong-sheng  FAN Xiao-fang  HU Liang-gang  CHEN Yan-fan  WANG Liang-xing 《园艺学报》2003,19(10):1365-1368

AIM: To investigate rat Urotensin-II(rat U-II)-induced vasoconstriction of rat main pulmonary arteries and the role of mitogen-activated protein kinase(MAPK). METHODS: The main pulmonary artery was dissected from the male Sprague-Dawley rats and artery ring width was 3-4 mm. Concentration-response curves were generated to rat U-II(0.03 nmol/L-30 nmol/L).Inhibitor of MAPK, PD 98059(0.1 μmol/L-10 μmol/L) were added into the medium after rat U-II(30 nmol/L)induced vasoconstriction had reached plateau to construct the relaxant concentration-response curves and their EC₅₀ and E_max. RESULTS：Rat U-II was a potent vasoconstrictor of isolated rat main pulmonary arteries [EC₅₀=7.95±0.40, E_max=(14.28±6.34)% of the response to 60 mmol/L KCl]; PD 98059 caused concentration-dependent relaxations of rat U-II precontracted arteries [EC₅₀=5.91±0.45, E_max=(81.39±13.65)%]. CONCLUSION: Rat U-II was a potent vasoconstrictor of rat main pulmonary arteries and this response was mediated through MAPK.  相似文献   

Influences of chronic hypoxia on the gene expression of Kv1.3,Kv2.1 and Kv3.1 induced by acute hypoxia in PASMC of rats     

HONG Zhi-gang  JIN Si  KONG Wei  WANG Di-xun  CHEN Qi-ling  SUN Bing-yong 《园艺学报》2002,18(10):1192-1195

AIM and METHODS: Total RNA was extracted from 6th rat subcultured pulmonary artery smooth muscle cells(PASMC) exposed to continual chronic hypoxia or normoxia and the effects of chronic hypoxia on the changes of Kv1.3,Kv2.1,Kv3.1 mRNA in cultured PASMC induced by acute hypoxia were studied by semiquantitative RT-PCR in vitro. RESULTS:①Kv1.3,Kv2.1,Kv3.1 genes were found to be expressed in PASMC of rats exposed either to hypoxia or normxia.②The expression of Kv2.1 and Kv3.1 in 6th subcultured of PASMC in normaxia group could be upregulated by exposure to acute hypoxia,the levels of Kv2.1 and Kv3.1 mRNA were significantly increased from 0.646±0.092, 0.782±0.104 to 1.059±0.134, 0.985±0.116,respectively (P<0.01,n=5). ③PASMC cultured continuously in chronic hypoxia for 6 subcultures and then exposed to normoxia for 12 h,thereafter the expression of Kv2.1 and Kv3.1 were downregulated by acute hypoxia for 6 hours.The level of Kv2.1 mRNA was significantly decreased from 1.008±0.117 to 0.649±0.097 (P<0.01,n=5). CONCLUSION:Kv2.1,Kv3.1 genes might be oxygen sensitive genes.Chronic hypoxia might change the response of these Kv genes of PASMC to acute hypoxia and down-regulate its expression,which might probably decrease the role of Kv in HPV.  相似文献   

Role of potassium channels in the regulation of intracellular free Ca²⁺ concentration of pulmonary artery smooth muscle cells in rats     

FAN Zai-wen  ZHANG Zhen-xiang  XU Yong-jian 《园艺学报》2004,20(2):150-153

AIM: To investigate the role of potassium channels in the regulation of intracellular free calcium concentration ( [Ca²⁺]_i) of pulmonary artery smooth muscle cells (PASMCs) in rats. METHODS: The fluorescence Ca²⁺ indicator Fura-2/AM was used to observe [Ca²⁺]_i of rat PASMCs in normal and chronic hypoxic condition. The influences of potassium channels on PASMCs proliferation were assessed by MTT assay. RESULTS: 1. In normoxic condition, [Ca²⁺]_i was (156.91±8.60) nmol/L, and in hypoxic condition, [Ca²⁺]_i was (294.01±16.81) nmol/L. 2. In normoxic condition, the voltage-dependent K⁺-channel antagonist 4-aminopyridine (4AP), but not the Ca²⁺-activated K⁺-channel antagonist tetraethylammonium (TEA) and the ATP-sensitive K⁺-channel antagonist glibenclamide (Glib) increased [Ca²⁺]_i. 3. In hypoxic condition, 4AP and TEA caused the rise in [Ca²⁺]_i , but Glib had no effect on [Ca²⁺]_i. 4. MTT assay showed that 4AP increased the value of absorbing light degree (A value) in normoxic and hypoxic condition (0.582±0.062,0.873±0.043,respectively, P＜0.01), TEA increased A value only in hypoxic condition, and Glib had no effect on the proliferation of PASMCs. CONCLUSIONS: K_V plays an important role in the regulation of [Ca²⁺]_i and proliferation of PASMCs. K_Ca serves as distinct responsive roles in the regulation of proliferation of PASMCs in hypoxic condition. K_ATP has no effect on [Ca²⁺]_i and proliferation of PASMCs in normoxic and hypoxic conditions.  相似文献   

Roles of the Kv1.2, Kv1.5, Kv2.1 potassium channels in hypoxia pulmonary vasoconstriction     

DU Yi-mei  TANG Ming  LIU Chang-jin  HONG Zhi-gang  KE Qin-mei  DI Jiu-fang  LUO Hong-yan  HU Mou-xian  HU Xin-wu  XI Jiao-ya  TANG Bi  Jurgen Hescheler 《园艺学报》2004,20(9):1537-1541

AIM: To determine the role of Kv1.2, Kv1.5, Kv2.1 in the hypoxia pulmonary vasoconstriction (HPV). METHODS: Male Wistar rats were divided into two groups: normoxic group and hypoxic group. The single smooth muscle cell was obtained from pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells (PASMC). Intracellular application of Kv1.2/Kv1.5/Kv2.1 antibodies (1∶125) was conducted through the whole-cell patch clamp system. RESULTS: ① Em of PASMC was depolarized after 24 h hypoxia compared with that of control cells . IKv of PASMC was decreased after 24 h hypoxia, . ② The mixture of Kv1.2/Kv1.5/Kv2.1 antibodies depolarized Em and inhibited IKv in PASMC from normoxic rat, whereas the mixture of Kir2.1/Kir2.3/Kir4.1 antibodies had no effects on them. ③ The mixture of Kv1.2/Kv1.5/Kv2.1 antibodies and the mixture of Kir2.1/Kir2.3/Kir4.1 antibodies had no effects on IKv and Em from rats hypoxic for 24 h. CONCLUSION: Kv1.2, Kv1.5, Kv2.1 might be oxygen sensitive potassium channels which mediated HPV.  相似文献   

A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators          下载免费PDF全文

C. Zizzadoro  M. Caruso  S. Punzi  G. Crescenzo  F. Zongoli  C. Belloli 《Journal of veterinary pharmacology and therapeutics》2018,41(1):51-59

Hemodynamic perturbations, partly resulting from abnormal vasoconstriction of digital vessels, have been implicated in the pathogenesis of bovine and equine laminitis. This study compared the responsiveness of isolated bovine (BDA) and equine (EDA) digital arteries to pharmacological agents that stimulate receptor systems involved in the regulation of normal vessel tone. The role of the endothelium and the short‐ and longer‐term effects of an experimentally induced endothelial damage were also evaluated. Species‐related differences were found in the vessel reactivity to all of the receptor agonists tested. In intact BDA, as compared to intact EDA, norepinephrine was a more effective vasoconstrictor, 5‐hydroxytryptamine a more effective but less potent vasoconstrictor, isoproterenol a less effective vasodilator and carbamylcholine a less potent vasodilator. In BDA, but not in EDA, the contractile responses to norepinephrine and 5‐hydroxytryptamine were enhanced immediately after endothelium removal. However, the contractile reactivity of denuded BDA returned to basal values following overnight incubation. The differences suggest species specificity for the pathophysiology of digital vasomotor tone and function in horses and cattle.  相似文献   

Anatomical variation of arterial supply to the rabbit spleen     

Reona IKEGAMI  Yoshimasa TANIMOTO  Miori KISHIMOTO  Hideshi SHIBATA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2016,78(2):199-202

The rabbit, which is widely used as an experimental animal and is also popular as a companion animal, has a flat and elongated spleen with the longitudinal hilus running along its visceral surface. The spleen receives via the hilus an arterial supply that is essential for splenic nutrition and normal functioning. However, the distribution and variation of the arteries to the spleen have not been studied in detail. This study investigated anatomical variations of splenic arterial supply in 33 New Zealand White rabbits with a colored latex injection into arteries. We also examined whether the length of the spleen correlated with the number of the splenic branches of the splenic artery. The splenic artery always arose as the first independent branch of the celiac artery and ran along the splenic hilus to usually provide 6 (range, 3 to 10) splenic branches to the spleen. There was a moderate correlation (R=0.6) between the number of splenic branches and the longitudinal length of the spleen. The splenic branches often arose as a trunk or trunks in common with short gastric arteries. The number of common trunk(s) was usually 1 (range, 0 to 4). The data showed that the pattern and number of arterial branches to the spleen varied according to the individual animal, suggesting that such variations should be considered when performing experimental and veterinary surgical treatments in rabbits.  相似文献