Search results for "acetylcholine."
showing 10 items of 620 documents
A quantitative study of the pancuronium antagonism at the motor endplate in human organophosphorus intoxication
1995
Nine patients with organophosphorus (OP) intoxication developing neuromuscular transmission defects were given pancuronium 1, 2, or 4 mg intravenously (IV). Thirteen patient controls with hypoxic encephalopathy received similar dosages. The responses were monitored electrophysiologically using single and repetitive nerve stimulation (20 and 50 Hz). In OP patients, pancuronium did not alter the amplitude of the single CMAP, whereas its repetitive discharges were reduced. Severe neuromuscular blocks were reversed only partially by pancuronium 4 mg. In less severe blocks, 1 and 2 mg resulted in marked improvement. In the patient controls, pancuronium 4 mg induced a severe neuromuscular block b…
Myasthenia gravis associated with Charcot-Marie-Tooth neuropathy: report of a case
1992
We report the case of a 24 year old woman who developed myasthenia gravis in the course of a mild form of Charcot-Marie-Tooth neuropathy. We describe the clinical manifestations together with the neurophysiological, pathological, serological findings and response to therapy and discuss the unusual association in the light of the relevant literature. © 1992 Masson Italia Periodici S.r.l.
Unit study in cat claustrum of the effects of iontophoretic neurotransmitters and correlations with the effects of activation of some afferent pathwa…
1982
Glutamate (Glut), acetylcholine (ACh) and dopamine (DA) were iontophoretically applied on cat claustral neurons. Glut did not affect all the neurons; ACh had both excitatory and inhibitory effects, while DA was prevalently inhibitory. An analysis was made of the time-course of excitatory and inhibitory responses on the basis of the mean firing rate variations during and after ACh and DA release. Three types of responses are described for each drug: short lasting inhibition, long lasting inhibition and long lasting excitation. The experimental data were statistically elaborated. The effects of ACh and of DA were compared with those of activation obtained by sensorial peripheric and thalamic …
Cognitive deficits in aged rats correlate with levels of l-arginine, not with nNOS expression or 3,4-DAP-evoked transmitter release in the frontopari…
2005
Aging is associated with altered neurotransmitter function in the brain. In this study, we measured release parameters for acetylcholine (ACh), norepinephrine and serotonin in the frontoparietal cortex of young and aged rats. We also determined cortical amino acid concentrations and nitric oxide (NO) synthase function. Prior to sacrifice, the rats had been tested for Morris water-maze performance. In aged, compared with young rats, we observed a reduction in both uptake of choline and acetylcholine release. Serotonin release and L-arginine concentrations (a precursor of NO) showed an aging-related increase; however, L-citrulline/L-arginine ratios were decreased in aged rats. Moreover, while…
Cellular Distribution and Expression of Cortical Acetylcholine Receptors in Aging and Alzheimer's Disease
1991
Ligand binding studies show marked reductions of nicotinic, but not of muscarinic binding sites in Alzheimer's disease. Using monoclonal antibodies we studied immunohistochemically the expression of the respective receptor proteins in the frontal cortex of middle-aged (55 +/- 5 yr) controls, age-matched controls (73 +/- 6 yr), and patients with Alzheimer's disease (74 +/- 5 yr). Density of nicotinic cholinoceptive neurons was 8000/mm3 for middle-aged controls and 4000/mm3 for age-matched controls, but only 900/mm3 in Alzheimer's brains (p less than 0.0001). Densities of muscarinic cholinoceptive and of Nissl-stained neurons were not significantly different between the groups, pointing to a …
Chapter 9 Nicotinic acetylcholine receptors on hippocampal neurons: cell compartment-specific expression and modulatory control of channel activity
1996
Publisher Summary The neuronal nicotinic acetylcholine receptors (nAChRs) are differentially expressed on the somato-dendritic surface of hippocampal neurons. This chapter demonstrates that various ions and drugs play a crucial role in modulating the activity of neuronal nAChRs. Considering the diversity of the neurotransmitter receptors and their binding sites and the diversity of substances, which can act simultaneously as a primary agonist of one receptor and an allosteric modulator of a different receptor, an enormous variety of combinatorial possibilities can be achieved in the brain giving rise to very complex neuronal networks. The characterization of the diversity of many receptors …
0149: Agonistic anti β3-adrenoceptor antibodies do not affect the β1-adrenoceptor-mediated inotropy and the β3 adrenoceptor-mediated vasorelaxation i…
2014
Cardiac activity of autoantibodies (AABs) directed against β1-adrenoceptor (β1-AR) has been proposed to play an important role in the pathogenesis of dilated cardiomyopathy. Our previous work has shown that the immunization of rats with the second extracellular loop (ECII) of β1-AR induced endothelial dysfunction in aorta and mesenteric arteries. However, until now, no study has explored the cardiovascular effects of β3-AABs alone or combined with β1-AABs.AimTo evaluate whether β3-AABs possess β3-AR agonistic effect and whether active immunization producing β3-AABs and/or β1-AABs has deleterious effects on cardiac and vascular reactivity in Lewis rats.MethodsLewis rats were immunized for 3 …
Neuronal nicotinic receptors in synaptic functions in humans and rats: physiological and clinical relevance.
2000
The present report describes the participation of nicotinic receptors (nAChRs) in controlling the excitability of local neuronal circuitries in the rat hippocampus and in the human cerebral cortex. The patch-clamp technique was used to record responses triggered by the non-selective agonist ACh and the alpha7-nAChR-selective agonist choline in interneurons of human cerebral cortical and rat hippocampal slices. Evidence is provided that functional alpha7- and alpha4beta2-like nAChRs are present on somatodendritic and/or preterminal/terminal regions of interneurons in the CA1 field of the rat hippocampus and in the human cerebral cortex and that activation of the different nAChR subtypes pres…
Effects of dantrolene on the responses to methylxanthines in the isolated guinea-pig trachea.
1991
The effect of dantrolene on the responses to methylxanthines (caffeine and theophylline) and a beta-adrenoceptor agonist (salbutamol) was studied in isolated guinea-pig trachea. Caffeine and theophylline (1 microM-10 mM) and salbutamol (1 nM-10 microM) produced concentration-dependent relaxation of spontaneous and stimulated (acetylcholine 1 mM) tone. Responses to high concentrations (10 mM) of caffeine and theophylline added to tracheal strips either unstimulated (spontaneous tone) or indomethacin (2.8 microM)-treated were reversed to contractions in the presence of dantrolene (3 microM-0.3 mM). This effect was not observed for salbutamol or when relaxant responses to the agonists were gen…
Behavioral effects of different enriched environments in mice treated with the cholinergic agonist PNU-282987.
2013
Abstract Environmental enrichment is an experimental model in which rodents are housed in complex environments that favor lower levels of anxiety-like behavior. PNU-282987 (PNU) is a α7 nicotinic acetylcholine receptor agonist with beneficial effects on learning though its effects on anxiety are unclear. Our main aim was to carry out a study of its effects in NMRI ( n = 96) mice reared in different environments: environmental enrichment (EE), Marlau™ cages (MC) and standard environment (SE). After a 4-month period, mice received acute treatment of PNU (2.5, 5 and 10 mg/kg) and were evaluated in the elevated plus-maze (EPM) and hole-board (HB). In the EPM, both EE and MC reared mice showed …