Search results for "Stimulation"
showing 10 items of 2192 documents
Electrical responses of pineal cells to melatonin and putative transmitters
1981
The effects of microelectrophoretically applied melatonin (N-acetyl-5-methoxy-tryptamine), noradrenaline (NOR) or acetylcholine (ACH) on the electrical activity of pineal cells during both the day- and night-time were studied in urethane anesthetised guinea-pigs. A total of 288 cells were tested with melatonin, and in addition with either NOR (120 cells) or ACH (138 cells). Of the 206 cells responding to melatonin application, 139 were excited and 67 inhibited. A total of 85 cells responded to the application of NOR, 45 being excited and 40 inhibited. Responses to ACH application were observed in 75 pineal cells, 49 units being inhibited and 26 excited. It was possible to observe excitation…
Muscarinic inhibition of acetylcholine release from a novel in vitro preparation of the guinea-pig trachea
1990
An isolated preparation of the guinea-pig trachea is described which allows the simultaneous measurement of acetylcholine release and smooth muscle contraction. Incubation of the epithelium-free preparation with [3H]choline resulted in the formation of [3H]acetylcholine. Electrical stimulation caused the release of [3H]acetylcholine and a contractile response. Tetrodotoxin and omission of calcium from the medium abolished both the evoked release and contractions. The muscarinic agonists oxotremorine, carbachol and pilocarpine concentration-dependently inhibited the electrically evoked acetylcholine release and contracted the tracheal smooth muscle. Pre- and postsynaptic EC50 values for a gi…
Effects of sulpiride on the orienting movement evoked By acoustic stimulation in the Rat.
2000
Abstract Drugs that selectively block D 2 receptors are known to provoke a rapid cell firing increase followed by A9 and A10 dopaminergic (DA) neuron inactivation (depolarization block). In this study, possible relationships between cell firing rapid increase and specific behavioral effects, linked to sensorimotor integration, were investigated in the rat. To this purpose, with the aid of a video camera apparatus and a frame-by-frame analysis, effects of sulpiride-induced blockade of DA D 2 receptors were analyzed on the orienting movement of the head induced by acoustic stimulation. In a control group of rats, during trials lasting 20 min, latency and duration of head turning (HT) were 186…
Auditory Neuropathy in Children
2001
Auditory neuropathy is a sensorineural disorder characterized by absent or abnormal auditory brainstem evoked potentials and normal cochlear outer hair cell function. A variety of processes is thought to be involved in its pathophysiology and their influence on hearing may be different. We present here the diagnostic sequence and management of two new cases of auditory neuropathy in breastfeeding children.
Effect of theophylline on calcium exchangeability in ventricular myocardium.
1976
The effects of theophylline on contractile force and myocardial calcium exchangeability were studied in isolated, electrically driven Langendorff perfused guinea-pig hearts. Following a 30-min exposure to 45Ca, total cellular calcium and 45Ca activity were measured in right ventricular samples. "Nontoxic" theophylline concentrations (5 x 10(-5) -10(-3) g/ml) which augmented contractile force without producing arrhythmias or contractures had no effect on total tissue calcium and did not alter the size of the fraction of cellular calcium exchangeable under steady-state conditions. A "toxic" concentration of theophylline (2 x 10(-3) g/ml) induced contractures and increased the amount of exchan…
A useful muscarinic parameter and the differential recording of atrial and ventricular tension in the perfused rabbit heart
1971
1. A simple method of recording right atrial tension from the Langendorff perfused rabbit has been described; it is based on the “transverse” method of recording cardiac contractions described by Beckett (1970). 2. Right atrial and ventricular tensions were recorded by transducers attached to threads stitched into the right atrium and right ventricle, the heart being retained and prevented from rotating by two threads stitched into the intraventricular septum as described by Beckett. 3. Right ventricular diastolic tension was adjusted to 7.5 g. Interference with the atrial record by ventricular systole was overcome by adjustment of diastolic right atrial tension to its optimal value between…
Effects of cerivastatin on adrenergic pathways, hypertrophic growth and TGFbeta expression in adult ventricular cardiomyocytes.
2010
Abstract The effects of statin treatment in the setting of heart failure have already been shown. Nevertheless, there is little knowledge about its influence on adrenergic pathways in cardiomyocytes. Therefore, this study investigated the impact of cerivastatin on adrenoceptor-mediated signalling pathways in isolated adult ventricular cardiomyocytes. It focused on two endpoints: hypertrophic growth and TGFbeta expression. Cultured cardiomyocytes were used to study rac activation (analysed by its translocation into the membrane fraction), ROS formation (H 2 DCF fluorescence) and hypertrophic growth ( 14 C-phenylalanine incorporation). Alpha- and beta-adrenoceptor stimulation showed significa…
A feasibility study of application and potential effects of a single session transcranial Direct Current Stimulation (tDCS) on competitive anxiety, m…
2020
Objective : To examine feasibility and potential effects of a single session tDCS over the dorsolateral prefrontal cortex (DLPFC) on competitive anxiety, mood state, and autonomic and endocrine stress responses in elite archer athletes under a real world competition. Methods : Twelve male elite archers volunteered to participate in this pilot trial. Participants were randomized in order to take left anodal DLPFC, left cathodal DLPFC, or sham stimulation (the F3 or F4 areas according to the 10/20 EEG International System) in a within-subject study design. This study included three official competitions. About 45 min before the competition, the tDCS stimulation process was started and the par…
Nitric oxide-sensitive guanylyl cyclase inhibits acetylcholine release and excitatory motor transmission in the guinea-pig ileum
1997
Abstract This study examined the mechanism through which nitric oxide inhibits the release of acetylcholine and excitatory motor neurotransmission in the guinea-pig ileum. The selective inhibitor of nitric oxide-sensitive guanylyl cyclase, 1 H -[1,2,4]oxadiazolo[4,3- a ]quinoxalin-1-one (ODQ), concentration-dependently enhanced both basal release (−log EC 50 : 6.8) and electrically (10 Hz) -evoked release (−log EC 50 : 6.0) of [ 3 H]acetylcholine from longitudinal muscle-myenteric plexus preparations preincubated with [ 3 H]choline. The increase by ODQ of basal release appeared to be exocytotic since it was prevented by tetrodotoxin (300 nM) and absence of calcium from the superfusion mediu…
Differential effects of isoliquiritigenin and YC-1 in rat aortic smooth muscle.
1997
We investigated the effects of isoliquiritigenin and YC-1 (3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole) on tension in endothelial-free rat aortic rings precontracted with phenylephrine (3 microM). Both compounds induced a concentration-dependent relaxation (EC50 of YC-1 1.9 microM and of isoliquiritigenin 9.4 microM). The effects developed faster with YC-1 than with isoliquiritigenin, and the effects of YC-1 were potentiated by isoliquiritigenin (10 microM). 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (30 microM) inhibited the effect of YC-1, but not of isoliquiritigenin. These results suggest that the effects of YC-1 are due to stimulation of soluble guanylyl cyclase activity, whereas …