Abstract:
:The aim of this study was to investigate the effects of melatonin on rat gastric fundus smooth muscle. Melatonin (10(-4) to 10(-3) M) had no effect on the basal tone of gastric smooth muscle. After precontraction with carbachol (10(-6) M) or serotonin (10(-7) M), melatonin caused a concentration dependent inhibitory action. The half maximal effect on serotonin-induced contraction was found with 1.12 +/- 0.86 x 10(-5) M of melatonin. Increasing concentrations of melatonin (10(-5) to 10(-3) M) resulted in a right shift of the serotonin concentration response curve (10(-10) to 10(-5) M). This inhibitory effect of melatonin was partially blocked in the presence of apamin (10(-10) to 10(-7) M), a specific blocker of the small conductance calcium-dependent potassium channel, but not in the presence of other potassium channel blockers like charybdotoxin (10(-8) M), glibenclamide (l0(-5) M), or tetraethylammonium (ODQ, 10(-4) M). The inhibitory effect was not changed in the presence of the neuronal blocker tetrodotoxin (10(-6) M), the selective P2-receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (3 x 10(-5) M), the nitric-oxide synthase inhibitor N-nitro-L-arginine (3 x 10(-4) M), or the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]-quinoxalin-1-one (10(-4) M), suggesting that neither the purinergic, nitrergic, nor guanylate cyclase pathways were involved. We further investigated inhibitory responses to electrical field stimulation (EFS) at different frequencies under non-adrenergic, non-cholinergic (NANC) conditions on a serotonin-induced contraction in the presence of melatonin (10)-5 to 10(-4) M). Melatonin significantly reduced these inhibitory NANC responses in higher (8-32 Hz), but not lower (05-4 Hz), frequencies (16 Hz without melatonin, 103 +/- 6.3%; melatonin 10(-5) M, 80.4 +/- 7.5%; melatonin 10(-4) M, 39.1 +/- 17.1%). Melatonin had no effect on contractile responses induced by EFS under basal tone. These results demonstrate that the inhibitory effect of melatonin in rat gastric fundus smooth muscle is apamin sensitive, but is not affected by other potassium channel blockers. This suggests that melatonin may be another transmitter candidate for the apamin sensitive responses within the gastrointestinal tract.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Storr M,Schusdziarra V,Allescher HDsubject
Has Abstractpub_date
2000-10-01 00:00:00pages
799-806issue
10eissn
0008-4212issn
1205-7541journal_volume
78pub_type
杂志文章abstract::The activation of mast cells (MC) due to immunological stimulation causes an immediate and dramatic inflammatory response. We review current evidence indicating that the membrane permeabilities for calcium, chloride, sodium, and potassium have a significant role in the activation of these cells, and in some cases, spe...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y92-001
更新日期:1992-01-01 00:00:00
abstract::Previous studies have demonstrated that the D-enantiomer of isoidide dinitrate (IIDN) is 10-fold more potent than the L-enantiomer for relaxation and cyclic GMP accumulation in isolated rat aorta. To test whether preferential biotransformation of D-IIDN to a species that activates guanylate cyclase is the basis for th...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-225
更新日期:1989-11-01 00:00:00
abstract::The role of sodium and calcium on strophanthidin inotropy was studied in canine cardiac Purkinje fibers perfused in vitro under conditions that vary cellular sodium and calcium. With high concentrations of strophanthidin (greater than or equal to 10(-7) M), force increases more in the presence of low [Ca]0 or high [Na...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y86-235
更新日期:1986-11-01 00:00:00
abstract::After myocardial infarction, the hemodynamics under basal conditions might appear to be unaltered, which makes it difficult to identify cardiac dysfunction by the usual approaches. Thus, we tested the response to sudden afterload stress in infarcted rats with apparently normal ejection function. Control (CT) and infar...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y10-062
更新日期:2010-07-01 00:00:00
abstract::Tea is perceived as more relaxing than coffee, even though both contain caffeine. L-theanine in tea may account for the difference. Consumed together, caffeine and theanine exert similar cognitive effects to that of caffeine alone, but exert opposite effects on arousal, in that caffeine accentuates and theanine mitiga...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2016-0498
更新日期:2017-01-01 00:00:00
abstract::Acrolein, a highly reactive alpha,beta-unsaturated aldehyde, is an omnipresent environmental pollutant. Chronic and acute human exposures occur through exogenous and endogenous sources, including food, vapors of overheated cooking oil, house and forest fires, cigarette smoke, and automobile exhaust. Acrolein is a toxi...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/Y09-134
更新日期:2010-03-01 00:00:00
abstract::The hemodynamic effects of the combination of clonidine and propranolol were studied in conscious rats with portal hypertension owing to secondary biliary cirrhosis. Pressure and blood flow measurements (radioactive microsphere method) were performed in three groups of eight rats before and after drug administration. ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-219
更新日期:1989-10-01 00:00:00
abstract::Our studies are guided by the novel hypothesis that protein tyrosine phosphorylation is an important mechanism for regulating contraction of smooth muscle. Several lines of evidence are reviewed which suggest that enhanced tyrosine phosphorylation participates in mechanisms that regulate cytosolic Ca2+ and Ca2+ sensit...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y94-207
更新日期:1994-11-01 00:00:00
abstract::The most commonly observed effect of beta-blockade on cardiovascular function has been a reduction in heart rate both at rest and during exercise. The body attempts to compensate by increasing stroke volume and (or) increasing the extraction of O2 from the blood to maintain O2 delivery to the muscle. This paper examin...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y91-044
更新日期:1991-02-01 00:00:00
abstract::The role of sympathetic innervation in the regulation of hindlimb skeletal muscle blood flow (QL) and metabolism was studied prior to and during acute anemia in anesthetized, paralyzed, and ventilated dogs (n = 8). Neural activity in the sciatic nerve was reversibly cold blocked for a 15-min period at control hematocr...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y88-189
更新日期:1988-09-01 00:00:00
abstract::Initially the impetus to develop iron (Fe) chelators for clinical use was based upon the need for a drug to treat Fe-overload diseases such as beta-thalassemia. However, it has become clear that Fe chelators may be useful for the treatment of a wide variety of disease states, including cancer, malaria, and free radica...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:
更新日期:1997-10-01 00:00:00
abstract::The recognition of chylomicrons as dietary lipid transporters dates back to more than 70 years and marks a milestone in lipoprotein history. Conventionally, three phases constitute the process of absorption of exogenous fat: intraluminal, intestinal, and delivery. The intraluminal phase includes chemical hydrolysis by...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y92-052
更新日期:1992-04-01 00:00:00
abstract::Administration of d-fenfluramine, a serotonin-releasing drug, to male rats induced a dose-dependent increase in both serum prolactin and corticosterone concentrations. Serum growth hormone levels increased, but not significantly, at a dose of 1.25 mg/kg i.p. and decreased significantly at higher doses. When rats were ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y87-388
更新日期:1987-12-01 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::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::Rats received a daily injection of 2, 6, or 12 mg kg-1 bethanechol for 7 or 14 days. Pancreatic weight and content of protein, amylase, and chymotrypsinogen were increased in a dose and time dependent fashion by bethanechol. After 14 days of treatment with the highest dose, pancreatic weight and total pancreatic DNA c...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y82-123
更新日期:1982-07-01 00:00:00
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 suppres...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y05-058
更新日期:2005-11-01 00:00:00
abstract::To investigate the contribution of pulmonary surfactant to a low airflow resistance through narrow conducting airways, a system was developed with which it was possible to determine the resistance meeting a steady flow of air at 0.5 mL/min. The airflow, delivered by an infusion pump, entered the extreme periphery of a...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:
更新日期:1996-06-01 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::Vascular smooth muscle tone is regulated primarily by the sarcoplasmic free Ca2+ concentration, which determines the level of myosin phosphorylation. Stimulation of the muscle results in an increase in free [Ca2+], whereupon Ca2+ binds to calmodulin, inducing a conformational change enabling calmodulin to interact wit...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y94-130
更新日期:1994-08-01 00:00:00
abstract::The metabolic effect of intravenous infusion of ammonium chloride (60 mumol/(kg body weight.min] was compared in five sheep before and after adrenal denervation. Adrenal denervation completely abolished the hyperglycemic effect of ammonium chloride, diminished the rise of pyruvate and lactate concentration, and failed...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y89-168
更新日期:1989-09-01 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::The objective of this study was to determine the influence of age on the learning and memory dysfunction induced by cranial radiation in the male Wistar rat. Ninety-six 45-day-old, 70 4-month-old, and 78 18-month-old male rats were divided in two equal groups: (i) irradiated and (ii) control. A course of whole-brain r...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y02-077
更新日期:2002-07-01 00:00:00
abstract::A brief summary is given of some of the key points of the individual contributions at this International Brain Research Organization satellite meeting, presenting up-to-date, expert knowledge of energy metabolism, ionic turnover, and cell swelling at the cellular level of the mammalian central nervous system. On the b...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y92-250
更新日期:1992-01-01 00:00:00
abstract::In embryonic chick hearts during development, there are three inward current systems which are involved in the rising phases of the action potentials (APs): fast INa, slow ICa, and tetrodotoxin-insensitive slow INa. To assess reactivation processes for these three types of inward current channels (fast Na+, slow Ca2+,...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y86-019
更新日期:1986-02-01 00:00:00
abstract::Xerostomia is a self-conscious symptom. High-mobility group box 1 (HMGB1) promotes pro-inflammatory effects in many diseases. This study aimed to clarify the role of HMGB1 in Sjögren syndrome (SS)-triggered xerostomia. Nonobese diabetic (NOD)/Ltj mice were used to establish an SS-triggered xerostomia model. The result...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/cjpp-2019-0337
更新日期:2020-06-01 00:00:00
abstract::Physical activity promotes metabolic adaptations that improve body functionality and contribute to the prevention of some diseases. With respect to energy and fat balance, physical activity facilitates the equilibrium between energy intake and expenditure as well as between fat intake and fat oxidation. When combined ...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章,评审
doi:10.1139/y05-132
更新日期:2006-02-01 00:00:00
abstract::In experiments on isolated guinea pig papillary muscles the effects of verapamil (5 mg/L) and caffeine (1 g/L) on the two-component contraction were investigated. The muscles were continuously superfused with normal Tyrode's solution containing 2 mg of noradrenaline/L at 20--22 degrees C. The first derivative of contr...
journal_title:Canadian journal of physiology and pharmacology
pub_type: 杂志文章
doi:10.1139/y79-132
更新日期:1979-08-01 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::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