Advances in myocardiology最新文献

Free radicals and myocardial ischemia. The role of xanthine oxidase. 自由基与心肌缺血。黄嘌呤氧化酶的作用。

Advances in myocardiology Pub Date : 1985-01-01

J M McCord, R S Roy, S W Schaffer

引用次数: 0

Influence of explantation procedure on the electrical and morphological properties of cultured neonatal rat ventricle cells. 外植程序对培养的新生大鼠脑室细胞电特性和形态学的影响。

Advances in myocardiology Pub Date : 1985-01-01

B Fermini, O F Schanne, J S Hugon

引用次数: 0

Identification of calcium-channel receptors in intact animals. 完整动物钙通道受体的鉴定。

Advances in myocardiology Pub Date : 1985-01-01

W R Roeske, H R Lee, H I Yamamura, H Schoemaker

引用次数: 0

Physiological and pharmacological analysis of transmembrane action potentials of human atrial fibers. 人心房纤维跨膜动作电位的生理药理学分析。

Advances in myocardiology Pub Date : 1985-01-01

V Kecskeméti, K Kelemen, F Solti, Z Szabó

{"title":"Physiological and pharmacological analysis of transmembrane action potentials of human atrial fibers.","authors":"V Kecskeméti, K Kelemen, F Solti, Z Szabó","doi":"","DOIUrl":"","url":null,"abstract":"Transmembrane action potentials (APs) of electrically paced right-atrial tissue obtained from 38 patients of corrective open-heart surgery were analyzed. Two types of APs could be found. The APs of 20 patients (group I) were similar to those of other laboratory mammals. The average resting potential (RP) and the amplitude and maximum rate of rise of phase 0 of APs (Vmax) were -75 mV, 86 mV, and 152 V/sec, respectively, only the repolarization phase being more prolonged than that of other mammalian APs. Epinephrine (5.8 X 10(-6) mole/liter) increased the amplitude of APs and prolonged the plateau phase, producing odd-looking, humped APs. Prostacyclin-Na (6.7 X 10(-7) and 8.7 X 10(-6) mole/liter) increased Vmax. Celluline-A (a biological Ca-complex obtained from frog skin) increased both Vmax and the amplitude of APs and, similar to epinephrine, prolonged the plateau phase. In group I, postoperative arrhythmias occurred in only 1 of the 10 patients. APs obtained from another 18 preparations (group II) were characterized by low RP (-55 mV), small amplitude of AP (59 mV), slow rate of rise of AP (less than 10 V/sec), and very prolonged repolarization. This type of APs can be referred to as slow-response APs. Neither epinephrine, prostacylin-Na, nor celluline-A modified the characteristics of these slow-response APs. In group II, postoperative arrhythmias could be observed in 8 of the 10 patients.","PeriodicalId":77831,"journal":{"name":"Advances in myocardiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15001957","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}

引用次数: 0

The role of Ca influx in cardiac muscle excitation-contraction coupling. Assessment by extracellular Ca microelectrodes. 钙内流在心肌兴奋-收缩耦合中的作用。细胞外钙微电极评价。

Advances in myocardiology Pub Date : 1985-01-01

D M Bers, D B Merrill

{"title":"The role of Ca influx in cardiac muscle excitation-contraction coupling. Assessment by extracellular Ca microelectrodes.","authors":"D M Bers, D B Merrill","doi":"","DOIUrl":"","url":null,"abstract":"Tension, dT/dt, and extracellular free [Ca] [( Ca]0) were continuously measured in isolated rabbit right papillary muscles at 28 degrees C. Double-barreled Ca-selective microelectrodes incorporating Simon's neutral Ca exchange resin (ETH-1001) were used to monitor [Ca]0. Decreases of [Ca]0 were seen during the course of single twitches, before the development of significant tension. This depletion of Ca0 probably represents Ca influx into the cells from the extracellular space. The magnitude of this Ca0 depletion is decreased by Co, verapamil, long rest intervals, and reduction of [Ca]0. The magnitude is increased by catecholamines, reduction of [Na]0, caffeine, continued pacing, and elevation of [Ca]0. After 3-min rest, stimulation (0.5-1 Hz) produces a biphasic tension response (larger first beat, small second beat, and monotonic rise to control). Caffeine (5 mM) changes the pattern after rest to a monotonic increase. Ca influx increases monotonically in both cases. Addition of 20 mM Co during the rest reduces tension of all beats by similar amounts in the presence of caffeine. In the absence of caffeine, Co has a much weaker effect on the first beat than on subsequent beats. The results suggest that caffeine inhibits an intracellular component of activator Ca that is more important after a rest interval, but that Ca influx becomes increasingly more important during continued pacing under the conditions used here.","PeriodicalId":77831,"journal":{"name":"Advances in myocardiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13724539","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}

引用次数: 0

Calmodulin in the regulation of calcium fluxes in cardiac sarcolemma. 钙调素在心脏肌膜钙通量调节中的作用。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1007/978-1-4757-1287-2_7

E Carafoli

引用次数: 7

Myocardial reoxygenation damage. Can it be circumvented? 心肌再氧损伤。它能被规避吗?

Advances in myocardiology Pub Date : 1985-01-01

S P Chappell, M J Lewis, A H Henderson

引用次数: 0

Calcium antagonists and myocardial protection during cardioplegic arrest. 心脏骤停期间钙拮抗剂与心肌保护作用。

Advances in myocardiology Pub Date : 1985-01-01

F Yamamoto, A S Manning, M V Braimbridge, D J Hearse

引用次数: 0

Influence of Na/K pump current on action potentials in Purkinje fibers. 钠钾泵电流对浦肯野纤维动作电位的影响。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1007/978-1-4757-1287-2_22

D C Gadsby

{"title":"Influence of Na/K pump current on action potentials in Purkinje fibers.","authors":"D C Gadsby","doi":"10.1007/978-1-4757-1287-2_22","DOIUrl":"https://doi.org/10.1007/978-1-4757-1287-2_22","url":null,"abstract":"Moderate changes in the size of the outward (hyperpolarizing) current that is generated directly by the electrogenic Na/K exchange pump in the surface membrane of cardiac Purkinje fibers can cause substantial alterations in the shape of the action potential, in the level of the diastolic potential, or of the resting potential of quiescent cells, or in the rate of firing of spontaneously active preparations. Transient increments in Na/K pump current, of suitable magnitude, can be elicited experimentally in small canine Purkinje fibers by causing a transient increase in their intracellular Na concentration, [Na]i, and, thereby, a transient increase in the rate of electrogenic Na extrusion. Two techniques were used to increase [Na]i: in the first, the rate of Na extrusion from the cells was temporarily reduced by omitting K ions from the bathing fluid for short periods of time, in the second, the rate of Na entry into the cells was temporarily increased by electrically stimulating the preparations rapidly (e.g., greater than or equal to 2 Hz) for brief periods. After the extracellular K concentration was restored, or after electrical stimulation was stopped, respectively, use of a two-microelectrode voltage-clamp technique allowed the resulting increments in pump current to be measured directly, as changes in holding current. Increments in pump current elicited by these two methods in the same preparation decline with the same exponential time-course. In preparations stimulated electrically at a regular, low rate (e.g., less than or equal to 1 Hz) both methods of temporarily stimulating the Na/K pump cause a marked, transient reduction in the duration of the action potential. A closely similar reduction in action-potential duration to that observed during enhanced pump activity can be elicited by injecting, from an external source, a steady hyperpolarizing current of magnitude similar to that of the increment in pump current recorded in the same preparation under voltage clamp.","PeriodicalId":77831,"journal":{"name":"Advances in myocardiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13722072","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}

引用次数: 5

Oxygen radicals and tissue damage in heart hypertrophy. 氧自由基与心肌肥厚的组织损伤。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1007/978-1-4757-1287-2_15

C Guarnieri, C Muscari, C M Caldarera

引用次数: 19