Search results for "hippocampus"
showing 10 items of 622 documents
Effects of Aging on the Structure and Expression of NMDA Receptors of Somatostatin Expressing Neurons in the Mouse Hippocampus
2021
Changes in the physiology, neurochemistry and structure of neurons, particularly of their dendritic spines, are thought to be crucial players in age-related cognitive decline. One of the most studied brain structures affected by aging is the hippocampus, known to be involved in different essential cognitive processes. While the aging-associated quantitative changes in dendritic spines of hippocampal pyramidal cells have already been studied, the relationship between aging and the structural dynamics of hippocampal interneurons remains relatively unknown. Spines are not a frequent feature in cortical inhibitory neurons, but these postsynaptic structures are abundant in a subpopulation of som…
Cannabinoid and nitric oxide signaling interplay in the modulation of hippocampal hyperexcitability: study on electrophysiological and behavioral mod…
2015
A growing bulk of evidence suggests that cannabinoid system plays a pivotal role in the control of hyperexcitability phenomena. Notwithstanding, the anticonvulsant action of cannabinoids has not been fully addressed, in particular the involvement of potential cellular neuromodulators, for instance nitric oxide. In the current study, we focused on two distinct rat models of temporal lobe epilepsy, the Maximal Dentate Activation and the pilocarpine-induced acute seizures, providing both electrophysiological and behavioral data on cannabinoid and nitrergic system interplay. We evaluated the antiepileptic effects of WIN 55,212-2, (R)-(+)-[2,3-dihydro-5-methyl-3-(4- morpholinylmethyl) pyrrolo[1,…
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…
Role of CB2 receptors and cGMP pathway on the cannabinoid-dependent antiepileptic effects in an in vivo model of partial epilepsy.
2014
This study aimed at providing an insight on the possible role of cannabi-noid (CB) type 2 receptors (CB2R) and cGMP pathway in the antiepileptic activity ofWIN 55,212-2, (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl) pyrrolo[1,2,3-de]-1,4-benzoxazin-6-Yl]-1-naphthalenylmethanone, a non-selective CB agonist, in the maximal dentate activation (MDA) model of partial epilepsy in adult male rats. We evaluated the activity of a CB2 antagonist/inverse agonist AM630, [6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl](4-methoxyphenyl)methanone or 6-iodopravadoline, alone or in co-administration with WIN 55,212-2. Also, in the MDA model it was investigated the co-treatment of WIN55,212…
Effects of pre- and postnatal exposure to 5-methoxytryptamine and early handling on an object-place association learning task in adolescent rat offsp…
2007
A reduction in 5-HT1A receptor response enhances learning and memory performance in rats. Pre- and postnatal treatment with 5-methoxytryptamine (5MT), a non-selective serotonergic agonist, and early handling, reduce the number of 5-HT1A receptors in neonatal and pre-pubertal rat progeny. The aim of this study was to investigate in adolescent male rats the consequences of pre- and postnatal treatment with 5MT and its interaction with early handling on an object-place association learning task, the "Can test", a motivated, non-aversive, spatial/object discrimination task. Results show that a single daily injection of 5MT from gestational days 12 to 21 (1 mg/kg s.c.) and from postnatal days 2 …
Choline is a Selective Agonist of α7 Nicotinic Acetylcholine Receptors in the Rat Brain Neurons
1998
In the present study, we demonstrate that choline, a precursor of acetylcholine (ACh) and a product of acetylcholine hydrolysis by acetylcholinesterase (AChE), acts as an efficient and relatively selective agonist of alpha7-containing nicotinic acetylcholine receptors (nAChR) in neurons cultured from the rat hippocampus, olfactory bulb and thalamus as well as in PC12 cells. Choline was able to activate postsynaptic and presynaptic alpha7 nAChRs, with the latter action resulting in the release of other neurotransmitters. Although choline was approximately one order of magnitude less potent than ACh (EC50 of 1.6 mM for choline and 0.13 mM for ACh), it acted as a full agonist at alpha7 nAChRs.…
Activation of phospholipases C and D by the novel metabotropic glutamate receptor agonist tADA.
1997
Abstract In hippocampal slices taken from 8-day-old rats, trans-azetidine-2,4-dicarboxylic acid (tADA), a novel glutamatergic agonist acting preferentially at class I mGluR receptors, activates phosphoinositide and phosphatidylcholine hydrolysis with widely different potencies. Inositol phosphate formation was maximally increased at 10 μM tADA ( ec 50: 1.2 μM), while phospholipase D activation was observed at a tADA concentration of 1 mM. This is the first report of a tADA-induced phospholipase D activity. © 1997 Elsevier Science Ltd. All rights reserved.
Fibroblast Growth Factor Receptor 1– 5-Hydroxytryptamine 1A Heteroreceptor Complexes and Their Enhancement of Hippocampal Plasticity
2011
Background The hippocampus and its 5-hydroxytryptamine transmission plays an important role in depression related to its involvement in limbic circuit plasticity. Methods The analysis was made with bioluminescence resonance energy transfer, co-immunoprecipitation, in situ proximity ligation assay, binding assay, in cell western and the forced swim test. Results Using bioluminescence resonance energy transfer analysis, fibroblast growth factor receptor 1 (FGFR1)-5-hydroxytryptamine 1A (5-HT1A) receptor complexes have been demonstrated and their specificity and agonist modulation characterized. Their presence based on co-immunoprecipitation and proximity ligation assay has also been indicated…
α7 Nicotinic acetylcholine receptors and modulation of gabaergic synaptic transmission in the hippocampus
2000
The present report provides new findings regarding modulation of gamma-aminobutyric acid (GABA) transmission by alpha7 nicotinic receptor activity in CA1 interneurons of rat hippocampal slices. Recordings were obtained from tight-seal cell-attached patches of the CA1 interneurons, and agonists were delivered to the neurons via a modified U-tube. Application for 6 s of the alpha7 nicotinic receptor-selective agonist choline (or =1 mM) to all CA1 interneurons tested triggered action potentials that were detected as fast current transients. The activity triggered by choline terminated well before the end of the agonist pulse, was blocked by the alpha7 nicotinic receptor antagonist methyllycaco…
Ontogenetic and Pharmacological Studies on Metabotropic Glutamate Receptors Coupled to Phospholipase D Activation
1997
The present study was aimed at characterizing the metabotropic receptor subtype which is involved in the activation of phospholipase D (PLD) by glutamate in rat hippocampal slices. We first observed that the ontogenetic profile of glutamate-induced hydrolysis of phosphoinositides and of phosphatidylcholine was strikingly similar. Both pathways were significantly activated by glutamate in tissue taken from 3-, 8- and 15-day old rats, but not in adult rats. PLD activation was strongest in slices taken from 8-day old rats. At this age, quisqualate had a higher potency for PLD activation (EC50: 0.6 microM) than 1S,3R-ACPD (EC50: 16 microM) and DHPG, a specific activator of group I mGluR, was a …