Abstract:
:The role of I(K) (delayed rectifier current) and I(f) (hyperpolarization-activated current) in dominant and subsidiary pacemaker ranges was studied in single myocytes isolated from the guinea pig sino-atrial node by means of a perforated patch-clamp technique. In the dominant pacemaker range (approx. -55 to -40 mV), I(K) tails are present whereas I(f) is not activated. In the subsidiary pacemaker range (approx. -80 to -70 mV), I(f) is large whereas I(K) is minimal and reversing. The threshold for I(f) activation is more negative at short time intervals. Larger or longer depolarizations to -40 mV and +20 mV deactivate I(f) more and are followed by faster reactivation of I(f). Steps of 200-300 ms duration to +20 mV completely deactivate I(f). The slope conductance decreases during depolarizations at -40 and +20 mV and quickly re-increases after the steps. The I(f) deactivation range is between -70 and +10 mV, with a V(1/2) of -35 mV. Depolarizations from -80 to +20 mV at a rate of 120/min limit the subsequent I(f) reactivation owing to the short diastole. We conclude that I(K) plays a predominant role in the dominant pacemaker range and I(f) does so in the subsidiary pacemaker range. Either pacemaker mechanism is used by sino-atrial node cells depending on the diastolic potential range. A previous depolarization markedly increases the amplitude and rate of I(f) reactivation.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Zhang H,Vassalle Msubject
Has Abstractpub_date
2001-12-01 00:00:00pages
963-76issue
12eissn
0008-4212issn
1205-7541journal_volume
79pub_type
杂志文章abstract::Previous studies have shown that when atrial natriuretic peptide (ANF) is given to anaesthetized dogs with hypovolemic acute pancreatitis, it will produce a diuresis and natriuresis but will not elevate the glomerular filtration rate (GFR). When the same dose of peptide is given to dogs equally hypovolemic (hemorrhage...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y90-099
更新日期:1990-06-01 00:00:00
abstract::Hedysarum polybotrys polysaccharide (HPS) is the principal active fraction responsible for the antidiabetic properties of this species. The aim of this study was to determine the antidiabetic properties of 4 purified fractions of different molecular weight range HPSs (HPS1, HPS2, HPS3, HPS4). HPS3 was selected for exa...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/Y09-098
更新日期:2010-01-01 00:00:00
abstract::The influence of external potassium Ko and tetraethylammonium on the cellular K content of hypoxic myocardium was investigated. Perfused rabbit hearts were submitted to 60 min hypoxia in medium containing 5 mM K throughout or either low (1.5 mM) or high (10 mM) K during the last 20 min of hypoxia. Paced electrical act...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y87-138
更新日期:1987-05-01 00:00:00
abstract::The connections of area postrema include a set of nuclei with a common topographical location immediately deep to the ependyma or pia mater. These nuclei are all within two principal synapses of the area postrema and can be reached by more than one route from it. There is direct evidence that, like the area postrema, ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y90-039
更新日期:1990-02-01 00:00:00
abstract::The development of cardiac hypertrophy was examined in rats given ethanol in a nutritionally adequate, liquid diet mixture, by intubation, in severely intoxicating doses at 8-h intervals for up to 96 h, alone or in combination with prazosin. Other groups of rats received isocalorically paired quantities of maltose-dex...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-040
更新日期:1989-03-01 00:00:00
abstract::The force generated by tracheal spirals and lung parenchymal strips from normal and ovalbumin-sensitized guinea pigs was measured in vitro, after challenge with histamine, carbachol, leukotriene (LT) C4, LTD4, or a prostaglandin endoperoxide analog (U-44069). The responses and sensitivity of airway tissues to the abov...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y83-133
更新日期:1983-08-01 00:00:00
abstract::Vanadium (V) as sodium orthovanadate induces an increase in lipid peroxidation in the kidneys after a single subcutaneous or intraperitoneal injection to rats or mice. The rate of malondialdehyde (MDA) formation, an index of lipid peroxidation, by kidney homogenates increased by more than 100% 1 h after injection. Chr...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y85-037
更新日期:1985-03-01 00:00:00
abstract::Transcranial magnetic stimulation over the motor cortex was used to construct a map of the effective sites on the scalp from which short-latency electromyogram responses could be evoked in muscles proximal to either an amputation stump (two subjects) or an ischemically anesthetized forearm (two subjects). At rest, the...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y95-032
更新日期:1995-02-01 00:00:00
abstract::The combined effect of a beta 2-antagonist and an alpha 2-agonist on the release of adrenal catecholamines was studied in the anaesthetized and vagotomized dog. The electrical stimulation of the splanchnic nerve (5-V pulses of 2 ms duration for 3 min at a frequency of 3 Hz) produced a significant rise in adrenal catec...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y88-219
更新日期:1988-10-01 00:00:00
abstract::The natural history of the disease of the dilated strain Bio TO-2 of cardiomyopathic hamsters (CMH) is not totally characterized. We investigated its hemodynamic and histomorphometric characteristics at 140, 180, 220, 260, and 300 days of age. Forty CMH and 40 controls were investigated (8 at each stage). Mean arteria...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:2001-04-01 00:00:00
abstract::Calcineurin was isolated from bovine cerebrum extracts by sequential chromatography on Affi-Gel blue and calmodulin affinity columns. Calcineurin so isolated was approximately 90% pure and was composed of equimolar amounts of subunit A (Mr = 61 000-63 000) and subunit B (Mr = 15 000-17 000) when examined by sodium dod...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y85-165
更新日期:1985-08-01 00:00:00
abstract::Changes in metabolic characteristics of the liver and jejunal epithelia as a result of feeding the beta-agonist albuterol to chickens for 3 and 6 weeks were studied. Feeding albuterol resulted in a change in weights of the liver and small intestines. Chickens fed albuterol for 6 weeks had greater levels of plasma none...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-069
更新日期:1989-05-01 00:00:00
abstract::The purpose of this study was to compare the specific cortisol-binding protein found associated with human amnion with specific cortisol binding in human amniotic fluid and plasma. The electrophoretic mobility on polyacrylamide gels of the specific cortisol binding in amnion, amniotic fluid, and maternal plasma was id...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y87-010
更新日期:1987-01-01 00:00:00
abstract::Urinary output of Na+ and K+, and volume of urine have been studied in conscious, unrestrained, water-loaded male rats following the intraseptal injection of catecholamines. Natriuresis and kaliuresis increased after injecting noradrenaline (NA), the intensity being dose related. The dose-response curve suggests that ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y76-034
更新日期:1976-06-01 00:00:00
abstract::In Sprague-Dawley rats, we attempted to develop an experimental model to stimulate the cardiac sympathetic nerve. After transverse thoracotomy under anesthesia, a miniature, bipolar electrode was placed on the right ansa subclavia and it was stimulated electrically. The nerve stimulation at 2, 4, and 8.3 Hz (2 ms in d...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1997-02-01 00:00:00
abstract::Premature weaning of rats to high carbohydrate diets causes a variety of short- and long-term changes in lipid metabolism, but the mechanisms involved are unclear. It is likely that interaction of diet with certain emerging hormonal control patterns during weaning might condition metabolic control and (or) subsequent ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y85-093
更新日期:1985-05-01 00:00:00
abstract::Spironolactone is a diuretic steroid which is capable of blocking the binding of aldosterone to its cytosol receptor at the distal convoluted tubule. In addition, it has been shown that spironolactone is a strong inhibitor of steroidogenesis. More recently, new aldosterone antagonists have been discovered. Some of the...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1983-01-01 00:00:00
abstract::Caffeine has been reported to have a positive and (or) a negative inotropic effect on cardiac muscle. In this study, the force-frequency and postrest characteristics of rat atrium were studied in the presence of caffeine (1.0-10 mM) to see if the interval between beats affected the response of cardiac muscle to caffei...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y92-034
更新日期:1992-02-01 00:00:00
abstract::Microglial inflammation, involved in the occurrence and development of sepsis-associated encephalopathy, exhibits upregulation of proinflammatory cytokine and proinflammatory enzyme expression, leading to inflammation-induced neuronal cell apoptosis. TIR domain containing adaptor molecule-2 (TICAM-2) participates in l...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2019-0699
更新日期:2020-11-01 00:00:00
abstract::We studied the effect of pertussis toxin (PT) treatment on the ability of insulin to inhibit lipolysis and to stimulate glucose oxidation in isolated rat adipocytes. In cells maximally modified by PT (100% ADP ribosylation of a 41-kdalton protein in membranes), the ability of insulin to inhibit lipolysis stimulated ei...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y85-167
更新日期:1985-08-01 00:00:00
abstract::The effects of a vasopressin (AVP) pressor antagonist, d(CH2)5Tyr(Me)AVP, on mean arterial pressure (MAP), total peripheral resistance (TPR), cardiac output (CO), and the distribution of CO were investigated by the microsphere technique in three groups of pentobarbital anesthetized rats: intact (I), saralasin pretreat...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y86-194
更新日期:1986-08-01 00:00:00
abstract::The objective of this work was to evaluate whether changes in respiratory status of isolated brown-fat mitochondria influence synthesis and degradation of proteins within the organelles. Mitochondrial protein synthesis is subject to regulation, as a 24-h fast in mice reduced [35S]methionine incorporation without affec...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y93-003
更新日期:1993-01-01 00:00:00
abstract::The inotropic response induced by beta-adrenergic and H1 histaminergic receptor stimulation was characterized in guinea pig left atria by obtaining dose-response relationships for isoproterenol and histamine under various experimental conditions. Conditions (hypothermia, high frequencies of stimulation, and large extr...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y78-147
更新日期:1978-12-01 00:00:00
abstract::Electrophysiological studies were performed on in vitro slice preparations of sympathetic ganglia excised from peripherally perfused, brain-dead human donors. The intracellular recordings in 16 neurons showed resting potentials and input resistances mostly in the ranges reported for sympathetic neurons in other mammal...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y88-138
更新日期:1988-06-01 00:00:00
abstract::Investigation of the relationship of diet to blood lipids and atherosclerosis has dominated the field of lipid nutritional biochemistry for the past 25 years. Although this subject has consumed considerable time, effort, and research funds, it has also proved beneficial to other areas of lipid biochemistry by attracti...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y83-040
更新日期:1983-03-01 00:00:00
abstract::Wound healing is important for longevity. Midkine is a cytokine involved in controlling tissue repair and new tissue development, and in regulating inflammation. We investigated the effect of midkine on wound healing in rats. In total, 108 Wistar albino rats were used: 12 as healthy and diabetic controls; 96 were spli...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2016-0439
更新日期:2017-05-01 00:00:00
abstract::In vivo fatty acid synthesis and the pathways of glycerol-3-phosphate (G3P) production were investigated in brown adipose tissue (BAT) from rats fed a cafeteria diet for 3 weeks. In spite of BAT activation, the diet promoted an increase in the carcass fatty acid content. Plasma insulin levels were markedly increased i...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y08-052
更新日期:2008-07-01 00:00:00
abstract::Persistent pulmonary hypertension of the newborn (PPHN) is defined as the failure of normal pulmonary vascular relaxation at birth. Hypoxia is known to impede postnatal disassembly of the actin cytoskeleton in pulmonary arterial myocytes, resulting in elevation of smooth muscle α-actin and γ-actin content in elastic a...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/cjpp-2014-0413
更新日期:2015-03-01 00:00:00
abstract::Chronic potassium deficiency in one-kidney one-clip hypertensive dogs significantly reduces blood pressure and plasma potassium, with a simultaneous increase in plasma renin activity. Tissue potassium concentration was decreased and tissue sodium concentration was increased in striated muscle and adrenal glands, which...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y83-210
更新日期:1983-12-01 00:00:00
abstract::Methionine sulfoximine (MSO) is a rare amino acid. It occurs in nature or as a by-product of some forms of food processing. A notable example of the latter was a former method for bleaching wheat flour, using nitrogen trichloride, the "agene process," in use for most of the first 50 years of this century. "Agenized" f...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1999-11-01 00:00:00