Abstract:
:The electrophysiologist's view of brain astrocytes has changed markedly in recent years. In the past astrocytes were viewed as passive, K+ selective cells, but it is now evident that they are capable of expressing voltage- and ligand-activated channels previously thought to be restricted to neurons. The functional importance of most of these ion channels is not understood at present. However, from studies of astrocytes cultured from different species and brain regions, we learned that like their neuronal counterparts astrocytes are a heterogeneous group of brain cells showing similar heterogeneity in their ion-channel expression. Not only are subpopulations of astrocytes within areas of the brain equipped with specific sets of ion channels but, furthermore, regional heterogeneity is apparent. In addition, astrocyte ion channel expression is dynamic and changes during development. Some ion channels are only expressed postnatally, yet others appear to be expressed only during certain stages of development. Interestingly, the expression of some astrocyte channels, including Na+, Ca2+, and some K+ channels, appears to be controlled by neurons via mechanisms that are presently unknown. Some studies suggest roles for astrocyte channels in basic cell processes such as cell proliferation. Thus, although the role of some astrocyte channels remains unclear, our understanding of astrocyte physiology is starting to take shape and points towards roles of ion channels not involved in electrogenesis.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Sontheimer Hdoi
10.1139/y92-266subject
Has Abstractpub_date
1992-01-01 00:00:00pages
S223-38eissn
0008-4212issn
1205-7541journal_volume
70 Supplpub_type
杂志文章,评审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::Over the past few years, a number of cases of tendon injuries associated with statin therapy have been reported. In this study, we assessed whether statins can affect the extracellular matrix (ECM) of the deep digital flexor tendon (DDFT) and patellar tendon (PT). Wistar rats were assigned to groups treated with atorv...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2016-0133
更新日期:2017-04-01 00:00:00
abstract::We have characterized a specific binding site for angiotensin II (AngII) in chicken liver membranes. Pseudo-equilibrium studies at 22 degrees C for 30 min have shown that this binding site recognizes AngII with a high affinity (pKD of 8.13 +/- 0.21). The binding sites are saturable and relatively abundant (maximal bin...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-75-6-568
更新日期:1997-06-01 00:00:00
abstract::A survey of 'steady-state' serum levels of anticonvulsant drugs from 221 epileptic patients at a university hospital was conducted. Serum concentrations of phenobarbital, primidone, and diphenylhydantoin were determined by a gas chromatographic method. Sixty-five percent (130) of the patients receiving diphenylhydanto...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y76-119
更新日期:1976-12-01 00:00:00
abstract::Mechanisms leading to ifosfamide (IF)-induced renal damage have not been fully elucidated. Recent work suggests that localized renal tubular metabolism of IF and the production of the nephrotoxic chloroacetaldehyde may lead to nephrotoxicity. Presently no pharmacological method to reduce IF nephrotoxicity has been ide...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y05-036
更新日期:2005-06-01 00:00:00
abstract::We have previously shown that A10 vascular smooth muscle cells (VSMC) exposed to angiotensin II (Ang II) exhibited overexpression of Giα proteins. In the present study, we examined the involvement of different signaling pathways in regulating Ang II induced enhanced expression of Giα proteins in VSMC by using pharmaco...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y2012-042
更新日期:2012-08-01 00:00:00
abstract::Coronary flow was recorded from spontaneously beating isolated perfused hearts of rats and guinea pigs. Arachidonic acid (AA), in single bolus doses, produced a fast short lasting coronary constriction followed by a slow developing but persisting vasodilation. These reactions (biphasic type) were characteristic of the...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y84-211
更新日期:1984-10-01 00:00:00
abstract::Our objective was to investigate the effects of chronic excess iodine intake on thyroid functions and thyroid oxidative stress state in hypothyroid rats. Sixty rats were divided into euthyroid and hypothyroid (thiocyanate-induced) groups with or without administration of excess iodine (3000 or 6000 μg/L) for 8 weeks. ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y2012-046
更新日期:2012-05-01 00:00:00
abstract::The aim of this study was to identify the key genes involved in the cardiac hypertrophy (CH) induced by pressure overload. mRNA microarray data sets GSE5500 and GSE18801 were downloaded from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) were screened using the Limma package; then, fun...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2017-0585
更新日期:2018-08-01 00:00:00
abstract::Epinephrine caused hyperglycemia in part by increasing gluconeogenesis. However, the mechanism of its gluconeogenic effects has not been studied in ruminants. This study was undertaken to examine the effect of epinephrine on the net hepatic uptake of selected glucose precursors in sheep. The major abdominal blood vess...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y91-071
更新日期:1991-04-01 00:00:00
abstract::It has been proposed that medullary washout secondary to increased blood flow will limit maximal urine osmolality and reabsorption of salt and water from the inner medullary collecting duct. We have tested this prediction. The function of the inner medullary collecting duct was examined by microcatheterization. Acetyl...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y87-383
更新日期:1987-12-01 00:00:00
abstract::The aim of this study was to demonstrate that within a population of healthy men (n = 15) of varying levels of aerobic fitness (VO2max = 36-74 mL.kg-1.min-1), (i) there are high and low responders with respect to carotid-cardiac baroreflex responsiveness, despite similar baseline heart rates (HRs) both at rest and dur...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 临床试验,杂志文章
doi:10.1139/y95-014
更新日期:1995-01-01 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::Although amiodarone is a highly efficacious antidysrhythmic agent, the drug produces numerous adverse effects. The most critical of these is pulmonary toxicity because of the potential for mortality. This review examines the experimental model systems used to study amiodarone toxicity, summarizes the current state of ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y95-730
更新日期:1995-12-01 00:00:00
abstract::The systemic and inotropic properties of prostaglandin E1 (PGE1) were investigated in 20 unanesthetized dogs. Pairs of ultrasonic dimension gauges and a micromanometer were implanted in the subendocardium and the apex of the left ventricle (LV), respectively. Seven to ten days later, increasing doses of PGE1 were infu...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y84-249
更新日期:1984-12-01 00:00:00
abstract::The precise role of microglia in stroke and cerebral ischemia has been the subject of debate for a number of years. Microglia are capable of synthesizing numerous soluble and membrane-bound biomolecules, some known to be neuroprotective, some neurotoxic, whereas others have less definitive bioactivities. The molecular...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/Y05-143
更新日期:2006-01-01 00:00:00
abstract::The effects of neurokinins (NK) and related peptides on the secretion of 6-keto-prostaglandin F1 alpha, a stable metabolite of prostacyclin, were measured. These peptides enhanced three- to five-fold the basal secretion rate with the following rank order of potency (based on threshold concentrations for a significant ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-026
更新日期:1989-02-01 00:00:00
abstract::Acetylcholine (ACh) is an important regulator of intestinal epithelial ion transport via muscarinic or nicotinic ACh receptors. Previous studies emphasize the role of the M3 muscarinic receptor subtype in mediating the effects of cholinergic agonists on intestinal ion transport. With the prevalence of mouse models to ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y06-068
更新日期:2006-11-01 00:00:00
abstract::The vasoconstrictors norepinephrine (NE) and angiotensin II (AII) mediate increases in oxygen uptake (VO2) by the constant flow perfused rat hind limb that are inhibited by quinidine-like membrane-stabilizing effects (involving the interruption of action potential) of (+/-)-propranolol with little effect on vasoconstr...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1998-02-01 00:00:00
abstract::Fetal and neonatal rats received daily subcutaneous injections of 10 microgram thyrotropin-releasing hormone (TRH) until 7 or 14 days postnatally. At 70 days the pups were challenged with 1 microgram TRH intravenously via an indwelling jugular cannula. Basal serum thyroxine, triiodothyronine, and thyroid-stimulating h...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y79-004
更新日期:1979-01-01 00:00:00
abstract::The effects of hydralazine (Hyd) on vascular smooth muscle contractile response to alpha-receptor stimulation by exogeneous and endogenous noradrenaline (NA) in the absence and presence of Mg2+ (1.2 mM) were examined using a proximal segment of rabbit's ear artery. Intraluminal perfusion with Hyd (2 x 10(-4) M) in nor...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y81-179
更新日期:1981-11-01 00:00:00
abstract::The effects of isoproterenol and forskolin on tension, cyclic AMP levels, and cyclic AMP dependent protein kinase activity were compared in helical strips of bovine coronary artery. Elevation of cyclic AMP and activation of the protein kinase appeared to be well correlated with relaxation of potassium-contracted arter...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y84-187
更新日期:1984-09-01 00:00:00
abstract::Extracellular spikes were recorded from cell bodies of sympathetic preganglionic neurones in spinal segments T1-T3 of the cat. Each neurone was identified by its antidromic response to electrical stimulation of the sympathetic chain and was found in histological sections to lie within the intermediolateral nucleus. Ph...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y84-198
更新日期:1984-09-01 00:00:00
abstract::We studied the effect of lowering the extracellular potassium concentration ([K+]o) on the electrophysiological actions of disopyramide phosphate, a new antiarrhythmic drug. At low [K+]o, therapeutic concentrations of disopyramide phosphate caused significantly less depression of action potential amplitude and maximum...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y78-018
更新日期:1978-02-01 00:00:00
abstract::Curare action on nicotinic acetylcholine receptors has a number of facets, of which the best known is competitive antagonism. Here we describe the weak agonist action of 10(-5) M curare on the murine skeletal muscle cell line, G8. Although curare induces no depolarization in G8 cells, single-channel recordings reveal ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-025
更新日期:1989-02-01 00:00:00
abstract::We studied the effects of Zn2+ and Cd2+ on the behaviour of IK(f), a transient outward potassium current in acutely dissociated melanotrophs of the pars intermedia of the rat pituitary gland. Micromolar concentrations of external Cd2+ or Zn2+ caused parallel and nearly equal rightward shifts along the voltage axis of ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y95-005
更新日期:1995-01-01 00:00:00
abstract::This study investigated the gastroprotective effects of N-acetylcysteine (NAC) against indomethacin-induced gastric ulcer in rats. Ulceration was induced by a single oral administration of indomethacin (30 mg/kg). 50 male albino rats were allocated into 5 equal groups: control group received normal saline orally, indo...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2016-0442
更新日期:2017-04-01 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 effects of neomycin sulfate were examined upon the discharge activity and electrical membrane properties of an isolated invertebrate sensory neuron, the crayfish stretch receptor neuron. Neomycin depressed cell discharge activity in a concentration-dependent manner over the concentration range of 0.01-1.0 mM. Sign...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y88-005
更新日期:1988-01-01 00:00:00
abstract::The effect of short-term exposure to homocysteine (Hcy) on the contractile characteristics of rat aortic tissue was assessed both in vitro and in vivo. The contractile response of Hcy-treated aortic rings in culture for 1 or 4 days was unchanged from control responses. By comparison, aortic rings from animals injected...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:2000-06-01 00:00:00