Search results for "Transmitter"
showing 10 items of 348 documents
Histamine and serotonin released from the rat perfused heart by compound 48/80 or by allergen challenge influence noradrenaline or acetylcholine exoc…
1994
Terminal nerve fibres of the autonomic nervous system closely approach mast cells in peripheral organs, and mutual influences between release of neurotransmitters or mast cell mediators may cause neuro-immunological interactions. We have studied the influence of mast cell degranulation on the release of endogenous noradrenaline and newly incorporated acetylcholine (such as 14C-choline/acetylcholine overflow) evoked by stimulation of extrinsic postganglionic sympathetic or preganglionic vagal nerves in the rat Langendorff heart perfused with Tyrode solution. Compound 48/80 perfused in normal hearts, or ovalbumin infused into hearts from rats sensitized to ovalbumin, enhanced the overflow of …
The effects of nitric oxide on striatal serotoninergic transmission involve multiple targets: an in vivo microdialysis study in the awake rat
2004
Abstract The role of endogenous nitric oxide (NO) in N -methyl- d -aspartate (NMDA)-induced modulation of serotonin (5-HT) release in the striatum of freely moving rats has been studied using microdialysis technique. NMDA-induced increase in 5-HT release was significantly inhibited by selective nitric oxide synthase (nNOS) inhibitor S -methylthiocitrulline (S-Me-TC), ONOO − scavenger l -cysteine ( l -cys), and guanylate cyclase (GC) inhibitor 1 H [1,2,4]oxadiazolo[4,3- a ]quinoxalin-1-one (ODQ). These data suggest that modulation of 5-HT levels is linked to the formation of NO produced by NMDA receptor activation and that endogenously produced NO increases 5-HT concentrations both by stimul…
Presynaptic effects of anandamide and WIN55,212-2 on glutamatergic nerve endings isolated from rat hippocampus
2006
We examined the effects of the endocannabinoide-anandamide (AEA), the synthetic cannabinoid, WIN55,212-2, and the active phorbol ester, 4-beta-phorbol 12-myristate 13-acetate (4-beta-PMA), on the release of [(3)H]d-Aspartate ([(3)H]d-ASP) from rat hippocampal synaptosomes. Release was evoked with three different stimuli: (1) KCl-induced membrane depolarization, which activates voltage-dependent Ca(2+) channels and causes limited neurotransmitter exocytosis, presumably from ready-releasable vesicles docked in the active zone; (2) exposure to the Ca(2+) ionophore-A23187, which causes more extensive transmitter release, presumably from intracellular reserve vesicles; and (3) K(+) channel block…
Distribution of origin of nitric oxide synthase-immunoreactive nerve fibers in the rat epididymis.
1996
Abstract Distribution of neuronal nitric oxide synthase-immunoreactive (nNOS-IR) nerve fibers and somata in the rat epididymis and major pelvic ganglia was studied by immunohistochemical methods. In the epididymis, the supply of nNOS-IR fibers was highest in the cauda and became progressively fewer toward the caput. In the cauda and corpus, nNOS-IR fibers were distributed throughout the subepithelial tissues and around the epithelium. The pattern of distribution of vasoactive intestinal polypeptide (VIP)- and tyrosine hydroxylase (TH)-immunoreactive fibers in the epididymis was similar but the latter was generally more numerous in a given region as compared to that of nNOS-IR fibers. A popu…
Interaction Between Uridine and GABA-Mediated Inhibitory Transmission: Studies In Vivo and In Vitro
1985
Na+-independent [3H]gamma-aminobutyric acid (GABA) binding to membrane preparations from frontal cortex, hippocampus, and thalamus is competitively inhibited by the in vitro addition of a naturally occurring pyrimidinic compound, uridine. Moreover, the intraperitoneal injection of uridine produces a dose-related decrease in the cerebellar content of cyclic GMP and antagonizes its increase elicited by bicuculline. The pyrimidinic compound also shows an antagonism toward bicuculline-induced seizures. The relationship between the anti-convulsant actions of uridine and GABA-mediated inhibitory neurotransmission is discussed in terms of an activation of GABA receptor function by the naturally oc…
Role of calcineurin in Ca2+-induced release of catecholamines and neuropeptides
1998
Neurotransmission requires rapid docking, fusion, and recycling of neurotransmitter vesicles. Several of the proteins involved in this complex Ca2+-regulated mechanism have been identified as substrates for protein kinases and phosphatases, e.g., the synapsins, synaptotagmin, rabphilin3A, synaptobrevin, munc18, MARCKS, dynamin I, and B-50/GAP-43. So far most attention has focused on the role of kinases in the release processes, but recent evidence indicates that phosphatases may be as important. Therefore, we investigated the role of the Ca2+/calmodulin-dependent protein phosphatase calcineurin in exocytosis and subsequent vesicle recycling. Calcineurin-neutralizing antibodies, which blocke…
Differential effect of beta-N-oxalylamino-L-alanine, the Lathyrus sativus neurotoxin, and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate …
2000
We studied the effect of beta-oxalylamino-L-alanine, a glutamate analog present in Lathyrus sativus seeds and implicated in the etiopathogenesis of neurolathyrism, and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate on the extracellular levels of aspartate, glutamate and taurine in the primary motor cortex of freely moving rats. We found that while both neurotoxins increase the level of aspartate and glutamate, only (+/-)-alpha(-amino-3-hydroxy-5-methylisoxazole-4-propionate is able to modulate the level of taurine. GYKI-52466, a non-competitive non-NMDA antagonist, inhibited beta-oxalylamino-L-alanine-induced increase of aspartate, but not that of glutamate. Conversely, this ant…
Continuous intra-amygdalar infusion of GABA in the amygdala kindling model of epilepsy in rat.
2003
Objective: To explore the effect of continuous intra-amygdalar infusion of GABA in the amygdala kindling model of epilepsy in rat. Methods: An electrode and cannula complex was implanted in adult male Wistar rats, the electrode being targeted to the left basolateral amygdala. The animals were subjected to a standard kindling procedure. Osmotic minipumps filled with either GABA or mannitol were connected to cannulas and allowed to infuse during 7 days. Kindling experiments measuring after-discharge and seizure thresholds, seizure severity and duration, and behavioral toxicity were performed before, during and after the drug infusion period. Results: Both after-discharge and seizure threshold…
Glucagon-like peptide-2 modulates neurally evoked mucosal chloride secretion in guinea pig small intestine in vitro
2009
Glucagon-like peptide-2 (GLP-2) is an important neuroendocrine peptide in intestinal physiology. It influences digestion, absorption, epithelial growth, motility, and blood flow. We studied involvement of GLP-2 in intestinal mucosal secretory behavior. Submucosal-mucosal preparations from guinea pig ileum were mounted in Ussing chambers for measurement of short-circuit current ( Isc) as a surrogate for chloride secretion. GLP-2 action on neuronal release of acetylcholine was determined with ELISA. Enteric neuronal expression of the GLP-2 receptor (GLP-2R) was studied with immunohistochemical methods. Application of GLP-2 (0.1–100 nM) to the serosal or mucosal side of the preparations evoke…
A novel miniature telemetric system for recording EEG activity in freely moving rats
2008
Telemetric recording systems offer the advantage to monitor physiological parameters in freely moving animals without any restrictions in their explorative behaviour. We present a novel, inexpensive, portable and reusable telemetric system to record the electroencephalogram (EEG) from adult freely moving rats under various experimental conditions. Our system consists of an implantable transmitter which communicates at a sampling rate of 500 Hz bi-directional with a receiver via radio transmission (in EU: 868.35 MHz; in USA: 916.5 MHz) over a distance of up to 3 m. The switching time between receiving and transmitting signals is 20s and the data transmission rate amounts to 115.2 kbps. The r…