Microcirculation, endothelium, and lymphatics最新文献

{"title":"Magnesium as a modifier of smooth muscle contractility.","authors":"H Karaki","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In smooth muscle, Ca2+ enters the cell through two different types of Ca2+ channels, activates contractile filaments and induces contraction. These Ca2+ channels are inhibited by Ca2+ channel blockers and/or nitrocompounds. Mg2+ inhibits both of these Ca2+ channels and relaxes the muscle. A portion of the smooth muscle contraction is due also to the release of Ca2+ from the cellular storage site. Caffeine and norepinephrine release Ca2+ from this store to induce a transient contraction. The contraction induced by caffeine is greatly augmented in the absence of Mg2+. The other effect of Mg2+ deficiency is to inhibit the effects of various vasodilators. Vascular endothelium releases a substance which relaxes vascular smooth muscle and this relaxation is also inhibited by Mg2+ deficiency. Thus, Mg2+ has multiple sites and mechanisms of action in smooth muscle which remain to be clarified.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"5 1-2","pages":"77-97"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13820662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divalent cation regulation of endothelial-dependent relaxation in coronary blood vessels.","authors":"D D Ku","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In the present study, effects of divalent cations, magnesium (Mg), calcium (Ca), barium (Ba) and strontium (Sr), in the regulation of the expression of endothelium-derived relaxant factor(s) (EDRF) in isolated canine coronary arteries were studied. Ca was found to stimulate, while Mg inhibits, the basal release of EDRF, such that a lowering of extracellular Mg (0-Mg) resulted in an \"unmasking\" of Ca-induced endothelium (EDRF)-dependent relaxation. Inhibition of the basal release of EDRF by the removal of extracellular Ca (0-Ca), in the latter 0-Mg condition, resulted in a complete reversal of the observed relaxation to a vasoconstriction. Reactivation of EDRF, in the latter 0-Ca and 0-Mg condition, with the re-addition of Ca (0.01-1.75 mM) again resulted in a dose- and endothelium-dependent relaxation with an ED50 of approx. 0.1 mM Ca. Sr (0.01-1.0 mM), but not Ba, was found to be equieffective as Ca in the activation of EDRF in this 0-Ca and 0-Mg condition and produced a similar dose- and endothelium-dependent relaxation. In endothelium-disrupted coronary arteries, however, both Sr and Ba were capable of mimicking Ca in producing a direct vascular smooth muscle cell contraction, as has been reported previously. These results demonstrate that divalent cations, in addition to their direct role in the regulation of vascular smooth muscle cell contraction, also play an important regulatory role in the expression of endothelium-dependent relaxation in coronary blood vessels.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"5 1-2","pages":"99-120"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13935920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of inorganic and organic promoters and inhibitors of calcium influx on stretch-induced myogenic tone of vascular tissues.","authors":"K Nakayama,&nbsp;S Yamada,&nbsp;Y Tanaka","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The static or dynamic stretch of helical strips or sudden increase of the transmural pressure produced contraction in cerebral and coronary arteries isolated from dogs and rabbits. The simultaneous recording of Ca transients and contractile activity showed that fluorescence intensity of fura-2 loaded cerebral artery increased during stretch activation. The contractile activation due to stretch was augmented by potentiators of Ca2+ influx, while it was attenuated by inhibitors of Ca2+ influx. The results suggest that contractile activation by mechanical stretch seems to provide a useful alternative technique to electrical and pharmacological stimuli for use in studies on contraction of vascular tissues and the effects of drugs and ions such as Ca antagonists and divalent cations which affect Ca2+ movement.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"5 1-2","pages":"55-76"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13696725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of calcium in the cardiac and vascular smooth muscle contraction--overview.","authors":"S Shibata","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"5 1-2","pages":"3-11"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13820665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Receptor-mediated Ca++ entry in blood vessels.","authors":"R K Hester","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The importance of receptor-mediated Ca++ entry (RMCa++E) relative to Ca++ release and potential-dependent Ca++ entry (PDCa++E) in agonist-induced responses in rabbit aorta and renal artery was quantitatively delineated by utilizing a solution without added Ca++ containing low ethyleneglycol bis(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA) plus D600 to inhibit PDCa++E. Adding an approximate ED80 concentration of norepinephrine (NE; 3 x 10(-7) M), histamine (Hist; 3 x 10(-6) M), or serotonin (5HT; 3 x 10(-6) M) to this solution results in a transient increase in developed force that is attributed to release of a limited cellular pool of Ca++. (NE greater than Hist much greater than 5HT). When the concentrations are approximately equipotent (NE, 3 x 10(-7) M; Hist, 3 x 10(-5) M; 5HT, 10(-5) M) the Ca++ release component increases for Hist and 5HT such that NE = Hist greater than 5HT. Subsequent addition of Ca++ results in an increase in developed force that is sustained and represents RMCa++E. In aorta, RMCa++E can account for 91% of the total NE-induced developed force; for an equipotent concentration of Hist, 71%; and for an equipotent concentration of 5HT, only 37%. This capacity for stimulating RMCa++E is inversely related to the sensitivity of these agonists to the PDCa++E blocker, D600 (5HT much greater than Hist greater than NE). Chronic Mg++ potentiates control responses to NE in normal Ca++, but depresses the sensitivity to Ca++ in the RMCa++E concentration response relationship. The sustained response associated with RMCa++E is only minimally relaxed or inhibited by Mg++ (acute) and is completely inhibited or slowly and completely relaxed by La . In renal artery, a similar approximate ED80 concentration of NE (3 x 10(-6) M) results in a NE-induced transient response attributed to Ca++ release that is 60% less than that seen in aorta, whereas the RMCa++E component in renal artery accounts for 78% of the total response (only 10% less than in aorta). Thus, it appears that there are pharmacologically distinct Ca++ channels in some blood vessels that are differentially activated in a selective and potential-independent manner as a result of specific agonist-receptor interactions.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"5 1-2","pages":"31-53"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13696257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of protein phosphorylation in Ca2+ regulated intracellular messenger systems.","authors":"H Hidaka,&nbsp;M Hagiwara,&nbsp;T Ishikawa,&nbsp;M Saitoh","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We investigated the effects of a newly synthesized compound 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine (ML-9), a myosin light chain kinase (MLC-kinase) inhibitor, on contractile responses and on phosphorylation of 20 KDa myosin light chain (LC20) in collagen induced human platelet, and the intact and skinned vascular smooth muscle cells. ML-9 were found to bind at or near ATP-binding site of MLC-kinase molecule and inhibit the enzyme activity in competitive fashion with respect to ATP, with a Ki value of 3.8 microM in the presence or absence of Ca2+-calmodulin. ML-9 had no or little effect on any other enzymes tested in vitro over similar concentration range to inhibit MLC-kinase. ML-9 delayed the time course of LC20 phosphorylation, sequentially led to a delay in aggregation and serotonin secretion in a dose-dependent fashion in collagen-induced human platelet. ML-9 (10 microM) produced a shift to the right and down in dose-response curves of rabbit vascular strips to all agonist tested. ML-9 also suppressed the Ca2+-induced contraction of saponin-treated skinned fibers. We then examined the relationship between ML-9-induced inhibition of isometric tension development after addition of 50 mM KCl and the extent of LC20 phosphorylation in vascular smooth muscle. ML-9 not only inhibited the maximal extent of LC20 phosphorylation but also delayed the time course of the phosphorylation, in a dose-dependent manner. The initial rate of isometric tension development correlated to the extent of phosphorylation of the LC20. Thus, ML-9 should prove to be a specific and potent MLC-kinase inhibitor for investigating the physiological role of myosin light chain phosphorylation by MLC-kinase, in vivo and in vitro.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"5 1-2","pages":"13-29"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13820659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the role of skin temperature in the response of cutaneous capillary blood flow to indirect heat.","authors":"D R Richardson,&nbsp;S Shepherd,&nbsp;T McSorley","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The purpose of this study was to test the hypothesis that the rise in cutaneous capillary blood flow that occurs while heating a remote region of the body; i.e., indirect heating, is mediated by an increase in local heat flux secondary to the opening of larger vessels; e.g. AVAs. Twelve unanesthetized rats were placed in a chamber and exposed to a 35 degree C environment while their tail remained unheated. Measurements of regional skin blood flow in the tail were obtained by a laser Doppler flowmeter (LDF) while measurements of blood cell velocity in individual capillaries (CBV) within the subepidermal vascular plexus were made by videodensitometry before and during body heating under two procedures: A control procedure in which skin temperature of the tail (TS) was allowed to increase as LDF increased, then under an experimental procedure during which TS was \"clamped\" at 25 degree C during body heating. During the control procedure TS increased from 24.5 to 33.2 degrees C while LDF increased by 404% and CBV increased by 89%. During the experimental heating procedure in which TS was clamped, respective increments in LDF and CBV were 414% and 72%. Respective changes in LDF and CBV between the control and experimental procedures were not significantly different. These results argue against local heat flux as a major mechanism for an increase in cutaneous capillary blood flow during indirect heating.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"4 6","pages":"447-67"},"PeriodicalIF":0.0,"publicationDate":"1988-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14384245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intermittent intra-aortic balloon tamponade during hemorrhagic shock.","authors":"K Avyash,&nbsp;G H Sigurdsson,&nbsp;Y Matani,&nbsp;I Francis,&nbsp;T Abu-Nema","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The use of intermittent intra-aortic balloon tamponade was evaluated during resuscitation of hemorrhagic shock in a sheep model. Twenty adult sheep were exposed to severe hemorrhagic shock and they were all treated with crystalloids (8% of body wt) during one hour. Ten of these were also treated with intermittent supraceliac intra-aortic balloon tamponade during the initial 30 min (group A) while the other 10 were used as a controls (group B). In the group treated with intra-aortic tamponade the mean arterial pressure (MAP) was rapidly increased as the balloon was inflated, but it dropped to the same level as in the control group during deflation. In this group there were also great fluctuations in systemic vascular resistance (SVR), pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) when the aortic balloon was inflated/deflated, while central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) were hardly affected at all. After final deflation of the aortic balloon (at 30 min), MAP remained 35% lower than the baseline value (p less than 0.01), similar to the control group. Cardiac index (CI) increased continuously during the first 30 min, at which time it reached the pre-shock level in both groups. At the end of the resuscitation period there was no significant difference between the two groups in any of the cardiovascular parameters measured. Four animals died in group A and 3 in group B within 24 hours, after which time the survivers were sacrificed. Both groups had high incidence of pathological changes in the kidneys, liver, intestine, and lungs. Six animals in group A had hind limb paralysis and loss of anal sphinter tone after the resuscitation. It was concluded that intermittent supraceliac aortic occlusion for 30 minutes did not decrease morbidity or mortality in sheep exposed to severe hemorrhagic shock compared with a control group treated in a traditional way with fluid replacement.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"4 6","pages":"419-31"},"PeriodicalIF":0.0,"publicationDate":"1988-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14384244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dose-response relationships between platelet activating factor and permeability--surface area product of FITC-dextran 150 in the hamster cheek pouch.","authors":"A Y Bekker,&nbsp;P K Dillon,&nbsp;J Paul,&nbsp;A B Ritter,&nbsp;W N Durán","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Changes in vascular permeability to FITC-dextran 150 associated with topical application of platelet activating factor (PAF) in the hamster cheek pouch preparation were calculated using a mathematical model (Baxter et al., Microvasc. Res. 34:336, 1987). Least square estimates of apparent permeability-surface area product (PS) and interstitial diffusion coefficient (D) were calculated from the data and the mathematical model using a Marquart optimization algorithm. Calculated PS products varied with applied PAF concentration while the best-fit estimate of apparent D remained constant at 10.5 X 10(-10) cm2/s. Average baseline PS was 16.5 X 10(-8) ml/s. PS increased to 45.2 X 10(-8) ml/s and 52.3 X 10(-8) ml/s with application of 10(-8)M and 10(-7)M PAF, respectively. A further increase in PAF concentration to 10(-6)M decreased the calculated PS product to 30.5 X 10(-8) ml/s. PAF is a potential modulator of macromolecular permeability in the microcirculation. This is the first study which quantitates the changes in PS of FITC-dextran 150 as a function of PAF concentration.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"4 6","pages":"433-46"},"PeriodicalIF":0.0,"publicationDate":"1988-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13622875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Histamine receptor on mast cells.","authors":"F Antohe,&nbsp;L N Dobrila,&nbsp;C Heltianu","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Mast cells isolated from the peritoneal fluid of Wistar rats were purified by centrifugation on Percoll gradient with a yield of 2x10(6) cells/ml. Cell morphology was well preserved as shown by light and electron microscopy. The mast cells capacity to bind histamine was assayed using either [3H]-histamine or histamine-ferritin conjugate as electron-opaque probe for electron microscopic examination. The [3H]-histamine binding performed at 4 degrees C in Ca2+-free phosphate-buffered saline pH 7.3 completed within 30 min was found to be specific, with an IC50 value of 0.72 +/- 0.23 nM. The data analyses by Scatchard and Hill's representations showed a KD of 0.60 +/- 0.24 nM and Bmax of 4.9 +/- 1.2 pM/10(6) cells suggesting that on mast cells the histamine receptors are restricted to the plasma membrane. According to Hill's analysis neither positive nor negative cooperativity (n = 1.06) appeared to be involved in the specific histamine-receptor binding. Competition experiments with 4-methylhistamine and SK&F 93479, revealed that mast cells express H2-histamine receptors. At electron microscopic level, the histamine-ferritin conjugate interstitially injected in the hamster cheek pouch was localized on the mast cell membrane.</p>","PeriodicalId":18718,"journal":{"name":"Microcirculation, endothelium, and lymphatics","volume":"4 6","pages":"469-88"},"PeriodicalIF":0.0,"publicationDate":"1988-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14384247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}