Abstract:
:We found when L-type calcium current (ICa-L) was recorded with the perforated patch-clamp method in rat ventricular myocytes that bath application of phenylephrine (with propranolol) evoked a biphasic response characterized by an initial transient suppression followed by a sustained potentiation. The transient suppression occurred 30-60 s after phenylephrine perfusion and reached peak inhibition at approximately 2 min. The biphasic modulation of ICa-L was also elicited by methoxamine, and the effects of phenylephrine were blocked by prazosin, indicating that the responses were mediated through alpha1-adrenoceptors. Pretreatment of cells with H7 (100 micromol/L), a broad-spectrum protein kinase inhibitor that inhibits both protein kinase C and A, eliminated potentiation but did not affect transient suppression. The transient suppression occurred concurrently with the acceleration of the fast component of ICa-L inactivation. Depletion of intracellular Ca2+ stores by ryanodine plus caffeine or thapsigargin eliminated the transient suppression. When ICa-L was recorded with whole-cell patch-clamp and with 0.05 mmol/L EGTA in the pipette solution to allow intracellular Ca2+ to fluctuate, phenylephrine evoked a transient suppression as in the perforated patch recordings. Heparin, a specific blocker of IP3 (inositol 1,4,5-trisphosphate) receptors, eliminated the phenylephrine-induced transient suppression of ICa-L when added to the pipette solution. Intensive chelation of intracellular Ca2+ by 5 mmol/L BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) in the pipette solution also eliminated the phenylephrine-induced transient suppression of ICa-L. We conclude that transient increase in the concentration of intracellular calcium ([Ca2+]i) caused by Ca2+ release from intracellular stores underlies the transient suppression of ICa-L, whereas the potentiation of ICa-L is a result of activation of protein kinases.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Zhang S,Lin J,Hirano Y,Hiraoka Mdoi
10.1139/y05-058subject
Has Abstractpub_date
2005-11-01 00:00:00pages
1015-24issue
11eissn
0008-4212issn
1205-7541pii
y05-058journal_volume
83pub_type
杂志文章abstract::Myometrial tissues from guinea pigs were quantitatively examined for gap junctions in electron micrographs. Small numbers of gap junctions were present between smooth muscle cells in myometria of pregnant guinea pigs at days 50 and 65 of gestation. The junctions increased in number and size at parturition on day 69 an...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y82-047
更新日期:1982-03-01 00:00:00
abstract::The electrical activity of the duodenum and proximal jejunum was studied in conscious healthy dogs implanted with unipolar silver electrodes. A computerized method was used for the calculation of the mean frequency of the slow wave for each consecutive minute of the electromyographic signal. A "slow wave frequency com...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y87-178
更新日期:1987-06-01 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 heat production (HP), heart rate (HR), respiration rate, rumen motility, and body temperature responses to 2.5-h adrenaline (A) and noradrenaline (NA) intrajugular infusions at 0.00, 0.15, 0.30, 0.60, and 0.90 micrograms.kg-1.min-1 were studied in 10 shorn wethers which had been chronically (3-8 weeks) exposed to ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y81-150
更新日期:1981-09-01 00:00:00
abstract::Immunocytochemistry, radioimmunoassay, chromatography, and biological assay using a rabbit isolated duodenal muscle strip preparation were used in attempting to characterize motilin from the rat small intestine. Several different antisera and monoclonal antibodies directed against natural porcine motilin were used. A ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y90-168
更新日期:1990-08-01 00:00:00
abstract::Microiontophoretic applications of ibotenate, an amino acid analogue of glutamate, evoked biphasic responses from single dorsal horn interneurones of the cat spinal cord, i.e., an initial increase in the firing rate followed by a sustained depression of spontaneous firing. A reduced cell sensitivity to excitatory amin...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y77-131
更新日期:1977-08-01 00:00:00
abstract::We investigated the role of receptor tyrosine kinases in Ang II-stimulated generation of reactive oxygen species (ROS) and assessed whether MAP kinase signaling by Ang II is mediated via redox-sensitive pathways. Production of ROS and activation of NADPH oxidase were determined by DCFDA (dichlorodihydrofluorescein dia...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y02-164
更新日期:2003-02-01 00:00:00
abstract::The influences of hypertension and hypothyroidism on diabetic cardiomyopathy are not clear. We studied this problem further by characterizing the effects of chronic triiodothyronine (T3) treatment on cardiac performance of diabetic renovascular hypertensive (RVH) rats. Hypertension was effected by clipping the left re...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y91-053
更新日期:1991-03-01 00:00:00
abstract::The 3,5-pyrazolidinedione (3,5-P) drugs, phenylbutazone and sulfinpyrazone, have been reported to bind to receptors for the chemotactic peptide, f-Met-Leu-Phe, and to behave as functional antagonists of f-Met-Leu-Phe in human and rabbit neutrophils. To explore the structure-activity relationship of this family of drug...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y91-064
更新日期:1991-03-01 00:00:00
abstract::Rapamycin, a new antifungal antibiotic, was found to inhibit the immune response in rats. It totally prevented the development of two experimental immunopathies (experimental allergic encephalomyelitis (EAE) and adjuvant arthritis (AA)) and the formation of humoral (IgE-like) antibody. It was about half as potent as c...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y77-007
更新日期:1977-02-01 00:00:00
abstract::In vitro coronary artery responsiveness to angiotensin I, angiotensin II, noradrenaline, phenylephrine, BHT 920, and potassium chloride together with functional relaxation to acetylcholine was investigated in dogs with pacing-induced heart failure treated with enalapril (oral administration of 10 mg.day-1) for a mean ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y92-199
更新日期:1992-10-01 00:00:00
abstract::Electrical stimulation of the diencephalon and rostral mesencephalon produced a biphasic pressor response consisting of an initial sharp rise followed by a more prolonged elevation in blood pressure. Active sites from which comparable responses could be evoked were found in the ventral medial and lateral hypothalamus,...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y81-072
更新日期:1981-05-01 00:00:00
abstract::The effect of neural inhibition on the electrical activities of circular and longitudinal colonic smooth muscle was investigated. In addition, a comparative study was carried out between circular muscle preparations with and without the "submucosal" and "myenteric plexus" network of interstitial cells of Cajal (ICC) t...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y90-063
更新日期:1990-03-01 00:00:00
abstract::Our previous results showed that addition of agonists, such as vasopressin and angiotensin, added to incubation medium with freshly excised rat atria caused marked release of atrial natriuretic factor (ANF). This release was in the form of prohormone rather than active peptide. Since others had difficulty reproducing ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-218
更新日期:1989-10-01 00:00:00
abstract::A single-dose administration of 6-hydroxydopamine (50 mg/kg body weight, sc) to infant rats resulted in an enlargement, higher fresh weight, markedly elevated lipid content, and higher total protein content of their interscapular and cervical brown adipose tissue. The protein kinase (EC 2.7.1.37) activation ratio in t...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y77-039
更新日期:1977-04-01 00:00:00
abstract::Opioid and N-methyl-d-aspartate (NMDA) receptors mediate different effects of fluoxetine. We investigated whether opioid and NMDA receptors are involved in the protective effect of fluoxetine against the behavioral despair induced by acute physical stress in male mice. We used the forced swimming test (FST), tail susp...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2015-0429
更新日期:2016-06-01 00:00:00
abstract::When carbon tetrachloride (CCl4) was administered to rats, a localized region of hepatic edema could be detected within 1 h by in vivo proton magnetic resonance imaging. However, if rats were pretreated with gadolinium chloride (GdCl3), an inhibitor of Kupffer cell function, the CCl4-induced edema was greatly decrease...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y94-064
更新日期:1994-05-01 00:00:00
abstract::Recent studies demonstrate the critical role of the extracellular matrix in the organization of parenchymal cells in the heart. Thus, an understanding of the modes of regulation of matrix production by cardiac myofibroblasts is essential. Transforming growth factor beta (TGF-beta) signaling is transduced through the c...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/Y09-076
更新日期:2009-10-01 00:00:00
abstract::The contribution of metabolic control to in vivo myocardial contractile function in response to beta 1-adrenergic stimulation was determined in the spontaneously diabetic BB Wor rat. The study involved a group of insulin-dependent BB Wor rats showing marked variations in metabolic control, assessed by the level of gly...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y94-103
更新日期:1994-07-01 00:00:00
abstract::Diazinon (DZN) is a common organophosphorus insecticide extensively used for agriculture and veterinary purposes. DZN toxicity is not limited to insects; it also induces harmful effects in mammals and birds. Our experiment evaluated the protective and antioxidant potential of sesame oil (SO) and (or) alpha-lipoic acid...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2015-0131
更新日期:2016-01-01 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
abstract::This study developed an animal model of gestational obesity and prediabetes in Sprague Dawley rats using 35% sucrose supplementation (SS). Postprandially, insulin stimulates glucose uptake and nutrient partitioning via insulin-dependent as well as Hepatic Insulin Sensitizing Substance (HISS)-dependent action. HISS is ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2020-0340
更新日期:2020-10-16 00:00:00
abstract::Radiolabelled acetylsalicylic acid (ASA) and salicylic acid (SA) were given intravenously to four near-term ewes and their occurrence in both maternal and fetal plasma was ascertained using a specific thin-layer chromatographic analysis procedure. Findings proved that ASA and SA cross the placental barrier and reach d...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y84-070
更新日期:1984-04-01 00:00:00
abstract::Space travelers experience anorexia and body weight loss in a microgravity environment, and microgravity-like situations cause changes in hypothalamic activity. Hypothalamic melanocortins play a critical role in the regulation of metabolism. Therefore, we hypothesized that microgravity affects metabolism through alter...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/Y09-074
更新日期:2009-10-01 00:00:00
abstract::Malnutrition and inflammation are associated with end-stage renal disease (ESRD). Interleukin (IL)-6 and tumor necrosis factor alpha (TNF-alpha) powerfully predict death from cardiovascular disease. The aim of our study was to establish an association between markers of inflammation and parameters of malnutrition in p...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/Y08-018
更新日期:2008-04-01 00:00:00
abstract::Intra- and extra-cellular concentrations of calcium were measured in hippocampal neurons of areas CA1 and CA3 during 8 min ischaemia and short-term (up to 60 min) recovery. During an ischaemic insult, [Ca2+]i increased progressively and [Ca2+]e decreased. There were large interneuronal differences, although, in genera...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y92-262
更新日期:1992-01-01 00:00:00
abstract::In urethane-anaesthetized rats, ion-selective microelectrodes recorded changes in extracellular K+ and Ca2+ concentrations (delta[K+]omicron and delta[Ca2+]omicron) in pyramidal layers of the hippocampus (mostly in area CA1), which were evoked by fimbrial-commissural stimulation. [K+]omicron increased linearly with fr...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y82-243
更新日期:1982-12-01 00:00:00
abstract::The contractile recoverability of isolated portal veins made hypodynamic by removal of glucose from the perfusion medium by diverse exogenous substrates was studied. It was found that glucose, mannose, pyruvate, lactate, acetate, and butyrate readily restored contraction. The effects of anoxia and metabolic inhibitors...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y80-115
更新日期:1980-06-01 00:00:00
abstract::In open-chest pentothal-chloralose anesthetized dogs, plasma catecholamine and cyclic AMP levels were evaluated in the aortic and coronary sinus blood, during stimulations of the left ansa subclavia (1, 2, and 4 Hz). Basal aortic and coronary sinus catecholamine levels were respectively 0.373 +/- 0.090 and 0.259 +/- 0...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y81-080
更新日期:1981-06-01 00:00:00
abstract::In both isolated canine ventricular trabecular muscle and Purkinje strand preparations, dl-sotalol and its two optical isomers d- and l-sotalol produced a concentration-dependent increase in action potential duration while other transmembrane electrical characteristics were not significantly affected. The magnitude of...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y85-248
更新日期:1985-12-01 00:00:00