Abstract：
:The validity of a Hodgkin-Huxley type voltage-dependent inactivation of slow inward Ca current (Isi) was tested in frog heart using a computer simulation. The time course of Isi was calculated during the development of a frog atrial action potential (AP). With a time constant of inactivation (tauf) of 55 ms at a membrane potential (Em) of -15 mV, the variation of Isi was biphasic: after a transient increase followed by a decrease to zero, Isi partially "reactivated" (at the beginning of the AP repolarization phase) and then fully deactivated. The "reactivation" phase of Isi developed whether tauf was an increasing, decreasing, U-shaped, or bell-shaped function of Em. The addition of an independent and slower process responsible for the recovery from inactivation only partly suppressed the "reactivation" phase. However, until now there was no experimental evidence supporting such a biphasic variation of Isi during AP repolarization. Thus our results indicate that the Hodgkin-Huxley type model of the voltage-dependence of Isi-inactivation process may not correctly represent the actual behavior of frog cardiac muscle.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Fischmeister R,Horackova Mdoi
10.1139/y82-172subject
Has Abstractpub_date
1982-09-01 00:00:00pages
1185-92issue
9eissn
0008-4212issn
1205-7541journal_volume
60pub_type
杂志文章abstract：:N,N-Diethyl-2-(1-pyridyl)ethylamine (E-2-P) produced 59 +/- 7% of the maximal response to histamine in guinea pig ileal longitudinal smooth muscle and antagonized the responses of this tissue to histamine. The estimated binding constant of E-2-P for the histamine receptor predicted a binding curve nearly coincident wi...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y80-198
更新日期：1980-11-01 00:00:00
abstract：:The present experiments were designed to evaluate vascular reactivity to angiotensin II in rats with experimental cirrhosis of the liver (induced with CCl4 and phenobarbital) before ascites appearance. The systemic pressor response to angiotensin II in conscious animals and the contractile effect of angiotensin II in ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y89-243
更新日期：1989-12-01 00:00:00
abstract：:Impaired nitric oxide (NO) activity is associated with an increase in blood pressure in rats. Voltage-regulated calcium channels are believed to participate in this hemodynamic event. To further test this hypothesis, we examined the effect of nimodipine and verapamil (calcium antagonists) on the pressor activity of di...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/cjpp-76-10-11-983
更新日期：1998-10-01 00:00:00
abstract：:The presence of different receptor populations within a given brain area can be effectively evaluated via the local injections of defined receptor agonists and antagonists. Using this approach, it has become evident that the nucleus basalis - cortical cholinergic pathway possesses an inhibitory GABAergic input to the ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y86-053
更新日期：1986-03-01 00:00:00
abstract：:This study investigated the potential of shikonin as an anticancer agent against liver cancer and an in vitro human hepatoma cancer model system. The HepG2 cell line was the hepatoma cancer model in the present study. The inhibitory effect of shikonin on the growth of HepG2 cells was measured by MTT assay. To explore ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/Y10-085
更新日期：2010-12-01 00:00:00
abstract：:As an activator of AMPK, the effect of AICAR on insulin signaling has not been investigated extensively. PI3K-Akt is a critical node involved in the insulin signaling pathway. We observed that concomitant with the activation of AMPK by AICAR, the protein level of PI3K p85α and the insulin-induced phosphorylation of Ak...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/cjpp-2015-0159
更新日期：2016-02-01 00:00:00
abstract：:Carbon monoxide (CO), a vasodilator, has been implicated as an activator of soluble guanylyl cyclase (sGC) to effect smooth muscle relaxation; however, this idea has not received universal support. The purpose of this study was to examine the effects of the sGC inhibitor 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：
更新日期：1997-08-01 00:00:00
abstract：:The alcohol oxidase membrane technique is available for measurement of ethanol in commercial fluids. In this paper we examined its usefulness for cat and human blood in comparison with gas-liquid chromatography (GLC). The membrane method proved to be simple, reproducible, accurate, and inexpensive. Analysis took 1-2 m...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y88-052
更新日期：1988-04-01 00:00:00
abstract：:Rats were fed on a diet containing 1% beta-guanidinopropionate (Gp) to deplete their muscles of creatine. The apparent energy reserves (creatine phosphate (CrP) + ATP) of rested state diaphragm muscle strips were found to be 79% depleted by this treatment. To determine if the effective energy reserves for contraction ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y82-019
更新日期：1982-02-01 00:00:00
abstract：:After the discovery of an inactive, putative renin precursor that could be proteolytically activated, and the proteases involved in vivo, Morris and co-workers directly demonstrated that renin is indeed synthesized as a "pro" form, and from genetic coding sequences they provided the structure of human prorenin. The ge...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y91-203
更新日期：1991-09-01 00:00:00
abstract：:Ah receptor in hepatic cytosols from adult cynomolgus monkeys (Macaca fasicularis) was identified and quantitated by its binding of the highly toxic chemical 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the carcinogens 3-methylcholanthrene, benzo[a]pyrene, and dibenz[a,h]anthracene. The concentration of Ah receptor ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y84-216
更新日期：1984-10-01 00:00:00
abstract：:Visual acuity was measured behaviorally in various groups of cats by using a two-choice discrimination procedure. Cats in group 1 were rendered strabismic soon after birth by sectioning the tendon of the lateral rectus muscle (unilateral esotropia); at adulthood, their visual acuity (VA) was evaluated, after which the...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y95-195
更新日期：1995-09-01 00:00:00
abstract：:Thyrotoxicosis, a condition in which there is an excessive amount of circulating thyroid hormones, leads to reduced glycogen content in different tissues. In this study we analyzed the effects of aerobic swimming training on liver, heart, and skeletal muscle glycogen content in experimentally induced thyrotoxicosis. W...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y2012-044
更新日期：2012-05-01 00:00:00
abstract：:The study was carried out to determine whether the diminished release of norepinephrine (NE) upon sympathetic activation in the presence of sotalol can be attributed to the blockade of beta-adrenoceptors in the liver. NE release from the liver was measured in hepatic venous blood collected during direct hepatic nerve ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y85-234
更新日期：1985-11-01 00:00:00
abstract：:The mesenteric vascular bed preparation of control and pinealectomized (PX) male Wistar rats was used to examine vascular reactivity to two concentrations each of norepinephrine, serotonin, angiotensin, and potassium. Vasoconstrictor responses to 50- and 100-ng injections of norepinephrine and 0.5- and 1.0-microgram i...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y80-049
更新日期：1980-03-01 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：:Inactivation of endothelin B receptors (ETB), either through selective pharmacological antagonism or genetic mutation, increases the circulating concentration of endothelin-1 (ET-1), suggesting ETB plays an important role in clearance of this peptide. However, the cellular site of ETB-mediated clearance has not yet be...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/Y10-041
更新日期：2010-06-01 00:00:00
abstract：:We used thermoluminescence, electron spin resonance, and viscosimetric measurements to establish whether or not a spice had been irradiated. Thermoluminescence, using the 1788 EN official protocol with an alternative method for the extraction of mineral impurities, led to proof of irradiation or proof of no treatment....
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：
更新日期：2001-02-01 00:00:00
abstract：:Serotonin (5-HT) acts as a neuromodulator and plays a critical role in brain development. Changes in 5-HT signaling during the perinatal period can affect neural development and may result in behavioral changes in adulthood. However, further investigations are necessary including both sexes to study possible differenc...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/cjpp-2020-0261
更新日期：2020-09-17 00:00:00
abstract：:The purpose of this study was to determine the interaction of three factors that modify twitch contraction amplitude in the rat gastrocnemius muscle in situ: posttetanic potentiation, fatigue, and caffeine. Posttetanic (200 Hz for 1 s) twitch responses were observed before and after 15 Hz stimulation for 6 min (group ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y87-046
更新日期：1987-02-01 00:00:00
abstract：:The blood volume of anesthetized rats was expanded acutely by 33% with donor blood while a caval snare was gradually tightened so that right atrial pressure (RAP) was prevented from rising (n = 6). In control experiments (n = 5) an aortic snare was used to hold mean arterial blood pressure near the values found in the...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y84-131
更新日期：1984-07-01 00:00:00
abstract：:We describe postsynaptic Ca2+ signals that subserve induction of two forms of neuronal plasticity, long-term potentiation (LTP) and long-term depression (LTD), in rat hippocampal neurons. The common induction protocol for LTP, a 1-s, 50-Hz tetanus, generates Ca2+ increases of about 50-Hz in dendritic spines of CA1 neu...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：
更新日期：1999-09-01 00:00:00
abstract：:Norethandrolone (NE) and other androgenic steroids have been shown to be renotropic in various species and have also been reported to have salutary effects in patients with diminished renal function. Renal cortical slices prepared from rats pretreated with NE showed an increased capability to concentrate p-aminohippur...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y75-104
更新日期：1975-10-01 00:00:00
abstract：:The active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3 or calcitriol), is known to inhibit the proliferation and invasiveness of many types of cancer cells, including breast, colon, pancreatic, prostate, and liver cancer cells. These findings support the use of 1α,25(OH)2D3 for the treatment of these t...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：10.1139/cjpp-2014-0452
更新日期：2015-05-01 00:00:00
abstract：:The binding of dantrolene to rabbit red blood cell (RBC) ghosts and bovine serum albumin as models of receptor sites was studied using fluorescence techniques. Dantrolene upon binding to rabbit RBC ghosts and bovine serum albumin showed fluorescence with emission maxima at 495 and 500 nm, respectively. Dantrolene boun...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y82-192
更新日期：1982-10-01 00:00:00
abstract：:alpha-Fluoromethylhistidine, a histidine decarboxylase inhibitor, induced a significant depletion in the hypothalamic, midbrain, and cortical brain histamine amounts in 12- and 3-month-old rats. In all three brain regions the most evident depletion occurred 2 h after treatment. In both groups of rats midbrain histamin...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y87-339
更新日期：1987-10-01 00:00:00
abstract：:Canadian Aboriginal people encompass diverse cultural groups, whose daily food patterns vary in regard to the kinds and proportions of indigenous foods. Standard dietary methods of assessing food consumption sometimes require modification to be understandable and acceptable to Aboriginal communities. Depending upon th...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y95-101
更新日期：1995-06-01 00:00:00
abstract：:The guanylin family of peptides has 3 subclasses of peptides containing either 3 intramolecular disulfide bonds found in bacterial heat-stable enterotoxins (ST), or 2 disulfides observed in guanylin and uroguanylin, or a single disulfide exemplified by lymphoguanylin. These peptides bind to and activate cell-surface r...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：10.1139/y11-050
更新日期：2011-08-01 00:00:00
abstract：:Guanine nucleotide binding proteins (G proteins) are largely grouped into three classes: heterotrimeric G proteins, ras-like or small molecular weight GTP binding proteins, and others like Gh. In the heart G proteins transduce signals from a variety of membrane receptors to generate diverse effects on contractility, h...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：
更新日期：2000-03-01 00:00:00
abstract：:Tachykinin receptors in guinea-pig airways were examined using radioligand binding techniques in lung homogenates, and using isolated bronchial segments. Binding of the NK1 selective radioligand 125I-labelled Bolton-Hunter [Sar9,Met(O2)11]substance P ([125I]BHSarSP) was saturable and of high affinity (KD, 0.26 nM). Th...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y95-126
更新日期：1995-07-01 00:00:00
