Search results for "Stimulation"
showing 10 items of 2192 documents
Muscarinic inhibition of endogenous noradrenaline release from rabbit isolated trachea: receptor subtype and receptor reserve.
1994
The aim of the present study was to characterize putative muscarine receptors on sympathetic nerve terminals in the rabbit trachea. Release of endogenous noradrenaline from in vitro incubated rabbit trachea was evoked by electrical field stimulation (3 Hz, 540 pulses) and quantified by high performance liquid chromatography with electrochemical detection. The muscarine receptor agonist oxotremorine inhibited the evoked release of noradrenaline completely at 1 mumol/l (EC50: 64 nmol/l). The concentration response curve was very steep (Hill coefficient of 2.3). Scopolamine shifted the concentration response curve of oxotremorine to the right (-log KB 8.48) demonstrating specific, inhibitory m…
Inhibition by interleukin-1 beta of noradrenaline release in rat spleen: involvement of lymphocytes, NO and opioid receptors.
1995
Effects of indomethacin, N omega-nitro-L-arginine (NNA) and naloxone, and of pretreatment with cyclophosphamide (CY), on the interleukin (IL)-1 beta induced inhibition of exocytotic noradrenaline release were investigated in the isolated, vascularly perfused spleen of the rat. Neurotransmitter release was evoked by perivascular electrical stimulation (4 Hz) and the overflow of endogenous noradrenaline was determined by HPLC with electrochemical detection. Perfusion of the spleen with Tyrode's solution containing IL-1 beta (100 pg/ml) for 90 min caused an inhibition of the stimulation-evoked noradrenaline overflow which persisted for at least 20 min after washout of the IL. The evoked overfl…
The sensorimotor and cognitive deficits in rats following 90- and 120-min transient occlusion of the middle cerebral artery
2012
Middle cerebral artery occlusion (MCAO) is the most commonly used method to study the neurological and histological outcomes and the pathological mechanisms of ischaemic stroke. The current work compares sensorimotor and cognitive deficits and the infarct volume in rats following a transient 90- or 120-min MCAO, which allows the appropriate behavioural tests to be chosen based on the goal and design of the experiment. In the beam-walking test, we found significant differences between the 90- and 120-min MCAO groups in the number of foot faults made with the impaired hindlimb on post-stroke days 3, 7 and 14. In the cylinder test, a difference between the 90- and 120-min groups was observed o…
Impaired cortico-bulbar tract function in dysarthria due to hemispheric stroke. Functional testing using transcranial magnetic stimulation.
1997
We investigated cortico-lingual and cortico-orofacial tract function utilizing transcranial magnetic stimulation in 18 consecutive patients with dysarthria due to hemispheric stroke. Delayed responses (conduction time > mean + 2.5 SD of that of 43 controls) or absent responses were considered abnormal. In all patients, motor-cortex stimulation of the lesion side demonstrated absent (13 patients) or delayed (five patients) responses to the tongue bilaterally (17 patients) or unilaterally (one patient). In 14 patients the contralateral orofacial responses were either absent (13 patients) or delayed (one patient). According to the electrophysiological findings, all lesions revealed by CT or MR…
The effects of LSD in the guinea-pig ileum
1985
The effects of lysergic acid diethylamide (LSD) on acetylcholine release and on smooth muscle tone were studied in the myenteric plexus-longitudinal muscle preparation of the guinea pig. LSD (0.01-10 microM) depressed in a concentration-dependent manner the electrically-evoked [3H]-acetylcholine outflow from strips preincubated with [3H]-choline. The maximal effect was a 45% inhibition by 1 microM LSD. The spontaneous outflow was not affected. Metitepine competitively antagonized (pA2 8.0) the LSD-induced reduction of the evoked outflow. Tolazoline and mepyramine did not affect the inhibitory action of LSD. The contractions in response to electrical stimulation were enhanced by 34% in the p…
Electromyostimulation Training Effects on Neural Drive and Muscle Architecture
2005
GONDIN, J., M., GUETTE, Y. BALLAY, and A. MARTIN. Electromyostimulation Training Effects on Neural Drive and Muscle Architecture. Med. Sci. Sports Exerc., Vol. 37, No. 8, pp. 1291–1299, 2005. Purpose: The purpose of the study was to investigate the effect of 4 and 8 wk of electromyostimulation (EMS) training on both muscular and neural adaptations of the knee extensor muscles. Methods: Twenty males were divided into the electrostimulated group (EG, N 12) and the control group (CG, N 8). The training program consisted of 32 sessions of isometric EMS over an 8-wk period. All subjects were tested at baseline (B) and retested after 4 (WK4) and 8 (WK8) wk of EMS training. The EMG activity and mu…
Platelet-activating factor contributes to the induction of long-term potentiation in the rat somatosensory cortex in vitro
2007
The contribution of platelet-activating factor (PAF) to the induction of neocortical LTP was examined in rat brain slices containing the primary somatosensory cortex (SI). Field potentials evoked by single pulse stimulation in cortical layer IV were recorded from layer II/III. In control experiments, tetanic high frequency stimulation (HFS) resulted in input-specific, NMDA receptor-dependent LTP (21.1+/-3.2%; mean+/-SEM; n=15; P0.001). BN-52021 (5 microM), an antagonist at the extracellular PAF receptor, weakened the HFS-induced LTP to 12.4+/-2.7% (n=11; P0.05). In contrast, HFS-induced LTP was significantly enhanced to 29.4+/-2.3% (n=11; P0.05) when brain slices were superfused with ACSF c…
Acute stress does not impair long-term memory retrieval in older people.
2013
Previous studies have shown that stress-induced cortisol increases impair memory retrieval in young people. This effect has not been studied in older people; however, some findings suggest that age-related changes in the brain can affect the relationships between acute stress, cortisol and memory in older people. Our aim was to investigate the effects of acute stress on long-term memory retrieval in healthy older people. To this end, 76 participants from 56 to 76 years old (38 men and 38 women) were exposed to an acute psychosocial stressor or a control task. After the stress/control task, the recall of pictures, words and stories learned the previous day was assessed. There were no differe…
Sex differences in nucleus accumbens transcriptome profiles associated with susceptibility versus resilience to subchronic variable stress
2015
Depression and anxiety disorders are more prevalent in females, but the majority of research in animal models, the first step in finding new treatments, has focused predominantly on males. Here we report that exposure to subchronic variable stress (SCVS) induces depression-associated behaviors in female mice, whereas males are resilient as they do not develop these behavioral abnormalities. In concert with these different behavioral responses, transcriptional analysis of nucleus accumbens (NAc), a major brain reward region, by use of RNA sequencing (RNA-seq) revealed markedly different patterns of stress regulation of gene expression between the sexes. Among the genes displaying sex differe…
Diagnostic subgroups of developmental dyslexia have different deficits in neural processing of tones and phonemes.
2004
The present study addressed auditory processing in 8-11-year-old children with developmental dyslexia by means of event-related brain potentials (ERP). Cortical sound reception was evaluated by recording N250 responses to syllables and tones and cortical sound discrimination by analyzing the mismatch negativity (MMN) to syllable and tone changes. We found that both cortical sound reception and sound discrimination were impaired in dyslexic children. The analysis of the data obtained from two dyslexic subgroups, Dyslexics-1 being impaired in non-word reading (or both non-word and frequent word reading) and Dyslexics-2 in frequent word reading but not in non-word reading, revealed that the MM…