Search results for "Postsynaptic potential"
showing 10 items of 371 documents
Postnatal alterations of the inhibitory synaptic responses recorded from cortical pyramidal neurons in the Lis1/sLis1 mutant mouse
2006
Mutations in the mouse Lis1 gene produce severe alterations in the developing cortex. We have examined some electrophysiological responses of cortical pyramidal neurons during the early postnatal development of Lis/sLis1 mutant mice. In P7 and P30 Lis1/sLis1 neurons we detected a lower frequency and slower decay phase of mIPSCs, and at P30 the mIPSCs amplitude and the action potential duration were reduced. Zolpidem (an agonist of GABAA receptors containing the alpha1 subunit) neither modified the amplitude nor the decay time of mIPSCs at P7 in Lis1/sLis1 neurons, whereas it increased the decay time at P30. The levels of GABAA receptor alpha1 subunit mRNA were reduced in the Lis1/sLis1 brai…
GABAA agonist muscimol ameliorates learning/memory deficits in streptozocin-induced Alzheimer’s disease non-transgenic rat model
2015
Background: GABAergic inhibitory action regulates learning/memory processes and contributes to neurotransmission (Gong et al., 2009). Existing evidence suggests GABAergic system is involved in pathophysiology of Alzheimer’s disease (AD) via inhibitory interneuron deficits (Verret et al., 2012) and decrease in functional GABAA receptors (Limon et al., 2012). In vitro, GABA and muscimol (GABAA receptor agonist) blocked neuronal death induced by Aβ in rat hippocampal and cortical neurons (Paula-Lima et al., 2005). Our concept: low doses of muscimol may prevent learning/memory deficits in intracerebroventricular (icv) streptozocin (STZ)-induced AD non-transgenic rat model. Methods. Wistar male …
Stressor-related impairment of synaptic transmission in hippocampal slices from α-synuclein knockout mice
2004
The role of alpha-synuclein (alpha-Syn) has recently received considerable attention because it seems to play a role in Parkinson's disease (PD). Missense mutations in the alpha-Syn gene were found in autosomal dominant PD and alpha-Syn was shown to be a major constituent of protein aggregates in sporadic PD and other synucleinopathies. Under normal conditions, alpha-Syn protein is found exclusively in synaptic terminals. However, the potential participation of alpha-synuclein in maintaining and regulating synaptic efficacy is unknown. We have investigated the excitatory synaptic modulation of alpha-synuclein in CA1 pyramidal neurons, using the in vitro hippocampal slice technique. The 4-am…
Targeted rescue of synaptic plasticity improves cognitive decline after severe systemic inflammation
2021
AbstractSepsis-associated encephalopathy (SAE) is a frequent complication in patients with severe systemic infection resulting in acute brain dysfunction and incapacitating long-term sequelae. SAE includes delirium, premature death, post-traumatic stress disorder, and major long-term cognitive impairment. The underlying pathophysiology of SAE is largely unresolved and specific treatment options are missing. We induced the peritoneal contamination and infection (PCI) sepsis model in 769 mice and compared these with 259 control mice. We found that experimental sepsis causes synaptic pathology in the brain characterized by severely disordered synaptic plasticity with reduced long-term potentia…
Involvement of purinergic nerves in the NANC inhibitory junction potentials in pigeon oesophageal smooth muscle.
2004
1. Electrical field stimulation (EFS) (0.5 ms in train of 2-32 Hz for 300 ms) in smooth muscle of pigeon oesophagus, in the presence of atropine (1 microm) and guanethidine (1 microm), elicited an inhibitory response consisting of a transient hyperpolarization (inhibitory junction potential, IJP) associated with muscle relaxation. 2. Sodium nitroprusside (SNP, 100 microm) induced hyperpolarization correlated to mechanical relaxation. 3. The nitric oxide (NO) synthase inhibitor N(omega)-nitro-l-arginine (from 0.1 to 100 microm) caused a concentration-dependent reduction of electromechanical response to EFS indicating a role for NO in this response. 4. Apamin (1 microm) reduced both IJP and r…
Non-adrenergic non-cholinergic nerve-mediated inhibitory control of pigeon oesophageal muscle.
1996
Pigeon oesophageal smooth muscle in vitro has spontaneous electromechanical activity. In the presence of atropine and guanethidine, electrical field stimulation evokes a transient TTX-sensitive response comprising inhibition of electric bursting activity and muscular relaxation. This NANC inhibitory response was analysed using the K+ channel blockers TEA and apamin, TEA perfusion (0.1-5 mM) induced a concentration-dependent reduction in amplitude of EFS-evoked relaxation. Responses to higher stimulation frequencies were more sensitive to TEA than those to lower ones. The maximum reduction in amplitude (29% of control) was obtained on 30 Hz EFS evoked responses during 5 mM TEA perfusion. In …
Short- and long-latency muscarinic inhibition of noradrenaline release from rabbit atria induced by vagal stimulation.
1988
1. The influence of the time interval between vagal and sympathetic nerve stimuli on the magnitude of muscarinic inhibition of noradrenaline release was studied in the isolated perfused rabbit atria preparation. The transmitter stores were labelled with [14C]choline and [3H]noradrenaline. 2. The right cardiac postganglionic sympathetic nerves were stimulated at 3 Hz for 3 min three times at intervals of 10 min. The [3H]noradrenaline outflow evoked by the second stimulation equalled the averaged means of the log values of amine outflows evoked by the first and third stimulations. 3. During the second sympathetic stimulation the right vagus nerve was stimulated (3 Hz, 3 min) in such a way tha…
Electrical stimulation of glossopharyngeal nerve and oesophageal EMG response in the pigeon
1985
The effects of the efferent glossopharyngeal nerve stimulation, on EMG activity of the pigeon cervical oesophagus, were studied. In control animals, stimulation caused a biphasic response characterized by an intra-stimulus excitatory component followed by a post-stimulus inhibitory one. The EMG response to glossopharyngeal stimulation appeared simultaneously throughout the cervical oesophagus. A bell-shaped mechanical wave was detected relating to the electrical excitatory component. Atropine administration antagonized the excitatory component, while the inhibitory one persisted. It occurs intra-stimulus, and its duration is increased, compared to control ones. A reduction in the oesophagea…
Primary peristalsis in pigeon cervical oesophagus: two EMG patterns.
1984
Swallowing elicits two propagated EMG peristaltic patterns in pigeon cervical oesophagus: i) "simple" peristaltic pattern and ii) "complex" peristaltic pattern. "Simple" peristaltic pattern is characterized by an intense, long-lasting burst of spikes, high in amplitude with an aboral increasing delay in onset. "Complex" peristaltic pattern presents an early short period of reduction in spontaneous electrical activity, followed by an excitatory period similar to that of "simple" pattern. The early inhibitory component has a very short delay in onset increasing aborally. Atropine abolishes the EMG excitatory component of both patterns, while the inhibitory period persists, showing increased d…
Electrophysiological and microiontophoretic analysis of the habenulo-hippocampal circuit.
1991
In the cat, the effects of lateral habenula stimulation, at different ranges of frequency, on hippocampal units were studied. Habenular stimulation at low frequency excited, while at high frequency inhibited the greater part of hippocampal units. Moreover, in order to clarify the possible pathway involved in the habenulo-hippocampal circuit, the effects of iontophoretic acetylcholine and serotonin on hippocampal units were compared with those of habenular stimulation. Iontophoretic acetylcholine induced both excitatory and inhibitory responses while serotonin induced only inhibitory responses. Iontophoretic atropine blocked the effects of acetylcholine ejection but did not antagonize stimul…