Search results for "Morin"
showing 10 items of 91 documents
Anti-inflammatory and antioxidant effects of muscarinic acetylcholine receptor (mAChR) activation in the rat hippocampus
2019
AbstractRecently we found that acute treatment with Oxotremorine (Oxo), a non-selective mAChRs agonist, up-regulates heat shock proteins and activates their transcription factor heat shock factor 1 in the rat hippocampus. Here we aimed to investigate: a) if acute treatment with Oxo may regulate pro-inflammatory or anti-inflammatory cytokines and oxidative stress in the rat hippocampus; b) if chronic restraint stress (CRS) induces inflammatory or oxidative alterations in the hippocampus and whether such alterations may be affected by chronic treatment with Oxo. In the acute experiment, rats were injected with single dose of Oxo (0.4 mg/kg) and sacrificed at 24 h, 48 h and 72 h. In the CRS ex…
Modulatory role of acetylcholine in the rat pineal gland
1998
Abstract The function of acetylcholine (ACh) in the mammalian pineal gland is unknown. To test the hypothesis that ACh exerts a modulatory role in this organ, in the present study electrophysiogical multiunit recordings were carried out in ex-vivo rat pineal glands superfused with different drugs. It was found that ACh (10 −7 M) as well as the cholinergic agonists oxotremorine (10 −7 M) and nicotine (10 −6 M) increased the discharge rates of most of the spontaneously active units and led to burst activity in previously regularly firing cells. It is concluded that ACh may play a modulatory role in the pineal by influencing the firing of a special population of pineal cells with perhaps recep…
Nicotinic and muscarinic modulation of 5-hydroxytryptamine (5-HT) release from porcine and canine small intestine
1992
Strips of porcine and canine small intestine were incubated in vitro and the release of 5-hydroxytryptamine (5-HT) was determined by HPLC with electrochemical detection. The spontaneous outflow of 5-HT from the porcine and canine small intestine largely reflects calcium-dependent 5-HT secretion from enterochromaffin cells which are under a spontaneous neuronal, excitatory input as indicated by the inhibitory effect (30-40%) of tetrodotoxin. In both species, nicotine enhanced the release of 5-HT in a concentration-dependent manner by a maximum of about 50% at 100 microM. This effect was blocked by the nicotine receptor antagonist hexamethonium, but not by the subtype-selective nicotine recep…
Applicability of the isolated perfused rat brain for studying central cholinergic mechanisms.
1974
The ACh content of the isolated perfused rat brain as well as that of the rat brain in vivo was determined by gas chromatography. After a perfusion period of 30 min the endogenous ACh content of the isolated brain was significantly higher than that of the brain in vivo. Physostigmine caused a rise in the ACh concentration of both the isolated brain and the brain in vivo. Oxotremorine produced an increase in the ACh content in the brain in vivo, but not in the isolated brain after appropriate dosage. The concentration of the drugs in the perfusion medium of the isolated brain was so that distinct EEG changes could be observed but spontaneous electrical activity could be maintained during the…
Muscarinic Control of Histamine Release from Airways
2000
Isolated human bronchi and rat tracheae were incubated in organ baths to measure histamine release. The calcium ionophore A23187, 3 micromol/L in rat trachea and 10 micromol/L in human bronchi, stimulated histamine release by 145 +/- 50% (n = 6) and 270 +/- 48% (n = 7) above the prestimulation level, respectively. Acetylcholine (100 pmol/L; human bronchi) or oxotremorine (1, 100, 10,000 nmol/L; rat trachea) did not affect the spontaneous histamine release. In rat tracheae neither acetylcholine nor oxotremorine inhibited A23187-evoked histamine release, whereas 100 pmol/L acetylcholine significantly suppressed the evoked histamine release in human bronchi by 86%. For receptor characterizatio…
Evidence that neuronally released vasoactive intestinal polypeptide inhibits the release of serotonin from enterochromaffin cells of the guinea pig s…
1991
Abstract. Isolated small intestinal segments of the guinea pig were arterially perfused and the release of serotonin (5-hydroxytryptamine) and 5-hydroxyindoleacetic acid into the portal venous effluent was determined by HPLC with electrochemical detection. Test substances were intra-arterially applied. The muscarine receptor agonist oxotremorine (1 μmol/l inhibited the release of 5-hydroxytryptamine by about 50%. In the presence of the neurotoxin tetrodotoxin, oxotremorine enhanced the release of 5-hydroxytryptamine by 145%, indicating that the inhibitory effect of oxotremorine was mediated by the release of a neurotransmitter. Exogenous vasoactive intestinal polypeptide ( 1-100 pmol/l inhi…
Cholinergic and GABAergic regulation of nitric oxide synthesis in the guinea pig ileum.
1999
Nitric oxide (NO) synthesis was examined in intact longitudinal muscle-myenteric plexus preparations of the guinea pig ileum by determining the formation of [3H]citrulline during incubation with [3H]arginine. Spontaneous [3H]citrulline production after 30 min was 80–90 dpm/mg, which constituted ∼1% of the tissue radioactivity. Electrical stimulation (10 Hz) led to a threefold increase in [3H]citrulline formation. Removal of calcium from the medium or addition of N G-nitro-l-arginine strongly inhibited both spontaneous and electrically induced production of [3H]citrulline. TTX reduced the electrically induced but not spontaneous [3H]citrulline formation. The electrically induced formation o…
Muscarinic inhibition of acetylcholine release from a novel in vitro preparation of the guinea-pig trachea
1990
An isolated preparation of the guinea-pig trachea is described which allows the simultaneous measurement of acetylcholine release and smooth muscle contraction. Incubation of the epithelium-free preparation with [3H]choline resulted in the formation of [3H]acetylcholine. Electrical stimulation caused the release of [3H]acetylcholine and a contractile response. Tetrodotoxin and omission of calcium from the medium abolished both the evoked release and contractions. The muscarinic agonists oxotremorine, carbachol and pilocarpine concentration-dependently inhibited the electrically evoked acetylcholine release and contracted the tracheal smooth muscle. Pre- and postsynaptic EC50 values for a gi…
Evaluation by reverse phase HPLC of [3H]acetylcholine release evoked from the myenteric plexus of the rat.
1990
Myenteric plexus-longitudinal muscle strips isolated from the small intestine of rats were incubated with [3H]choline to measure the synthesis and the release of [3H]acetylcholine. To separate different radioactive compounds (acetylcholine, choline, phosphorylcholine) from both the tissue and the overflow a new method, the reverse phase HPLC, was used. The radiochromatogram following the injection of a [3H]choline-standard and a [14C]acetylcholine-standard onto the HPLC showed a clear separation of both isotopes with a recovery rate of roughly 100%. Incubation of the muscle strips with [3H]choline caused the synthesis of [3H]acetylcholine (30,000 dpm/preparation) that increased 2-fold, when…
Presynaptic effects of scopolamine, oxotremorine, noradrenaline and morphine on [3H] acetylcholine release from the myenteric plexus at different sti…
1987
The inhibition by three modulators (oxotremorine, noradrenaline, morphine) of acetylcholine release from the myenteric plexus preincubated with [3H]choline was investigated at different stimulation frequencies and calcium concentrations. Moreover, [3H]acetylcholine release evoked by a low (0.1 Hz) or a high (10 Hz) stimulation rate was investigated at different calcium concentrations either in the absence or presence of scopolamine. A reduced calcium concentration (0.6 mmol/l) inhibited acetylcholine release more at 0.1 Hz (74% +/- 3%) than at 10 Hz (44% +/- 8%). Scopolamine enhanced the stimulated acetylcholine release at a calcium concentration of 1.8 mmol/l. At calcium concentrations hig…