Search results for " Neurotransmitter"
showing 10 items of 62 documents
Brain met-enkephalin immunostaining after subacute and subchronic exposure to benzene
1994
Benzene is used in a wide variety of domestic and occupational activities, and due to its lipophilic nature, it accumulates in lipid-rich tissues like the brain. In this sense, neurotoxic action has long been associated with organic solvent exposure and it has been shown that benzene, injected in a single dose or during a prolongued administration, modifies the content of dopamine, noradrenaline, serotonin and its main metabolite 5-hydroxy indolacetic acid, in several brain regions of the rat, then revealing a stimulating action on brain monoamine synthesis and turnover. However, information concerning neurotoxic action of benzene exposure in vivo on peptidergic neuromodulatory systems is s…
Changes in the expression of neurotransmitter receptors in Parkin and DJ-1 knockout mice – A quantitative multireceptor study
2015
Parkinson's disease (PD) is a well-characterized neurological disorder with regard to its neuropathological and symptomatic appearance. At the genetic level, mutations of particular genes, e.g. Parkin and DJ-1, were found in human hereditary PD with early onset. Neurotransmitter receptors constitute decisive elements in neural signal transduction. Furthermore, since they are often altered in neurological and psychiatric diseases, receptors have been successful targets for pharmacological agents. However, the consequences of PD-associated gene mutations on the expression of transmitter receptors are largely unknown. Therefore, we studied the expression of 16 different receptor binding sites …
Neurotransmitter receptor density changes in Pitx3ak mice – A model relevant to Parkinson’s disease
2014
Abstract Parkinson’s disease (PD) is the second most common neurodegenerative disorder, characterized by alterations of nigrostriatal dopaminergic neurotransmission. Compared to the wealth of data on the impairment of the dopamine system, relatively limited evidence is available concerning the role of major non-dopaminergic neurotransmitter systems in PD. Therefore, we comprehensively investigated the density and distribution of neurotransmitter receptors for glutamate, GABA, acetylcholine, adrenaline, serotonin, dopamine and adenosine in brains of homozygous aphakia mice being characterized by mutations affecting the Pitx3 gene. This genetic model exhibits crucial hallmarks of PD on the ne…
Adolescent pre-exposure to ethanol or MDMA prolongs the conditioned rewarding effects of MDMA
2011
Adolescents often take ethanol (EtOH) in combination with MDMA (3,4-methylenedioxymethylamphetamine). In the present work we studied the effect of repeated intermittent adolescent pre-exposure to both drugs on the behavioral and neurochemical effects of MDMA in mice. Sixteen days after pre-treatment, the rewarding and reinstating effects of MDMA in the conditioned place preference (CPP) paradigm were evaluated, along with the levels of biogenic amines, basal motor activity and corticosterone response to different challenges. Pre-exposure to EtOH, MDMA or EtOH+MDMA did not affect the CPP induced by 10mg/kg of MDMA. However, adolescent exposure to EtOH or MDMA increased the duration of the co…
Melatonin binding sites in brain of the 2-day-old chicken: An autoradiographic localisation
1990
Melatonin, released in a circadian manner from the avian pineal gland into the circulation, is concentrated in distinct brain areas, possibly by receptor-mediated uptake mechanisms. For anatomical localisation of putative melatonin receptors in birds, cryostat-cut, coronal 15 microns brain sections of 2-day-old chicken were investigated by means of in vitro receptorautoradiography, using 125I-melatonin as a ligand. Binding occurred in brain structures receiving or mediating visual or auditory sensory input. Binding characteristics were investigated in homogenates of a brain region labelled by 125I-melatonin and showed to be specific and saturable (Kd: 87.2 pM; Bmax: 16.1 fmol/mg protein). R…
Day- and night-time contents of monoamines and their metabolites in the medial preoptic area of the rat hypothalamus.
1999
The present study was conducted to investigate whether monoamines and their metabolites in the medial preoptic area (mPOA) of the rat hypothalamus exhibit differences in their contents between day and night. We therefore sampled the mPOA from adult animals of either sex at the middle of the light or dark period, respectively, and analyzed the tissue by means of high performance liquid chromatography with electrochemical detection. We found that, in female animals at mid-night, dopamine and 3,4-dihydroxyphenyl acetic acid (DOPAC) was reduced to 43 and 30%, respectively, of daytime levels, while the norepinephrine content was doubled. No significant differences were observed in male animals. …
Prenatal cocaine alters later responses to morphine in adult male mice.
2006
Mice prenatally exposed to cocaine (25 mg/kg), physiological saline or non-treated during the last 6 days of pregnancy were evaluated as adults for the rewarding properties of 2 mg/kg of morphine, using the conditioned place preference (CPP) procedure. Likewise, isolated animals underwent a social interaction test with conspecifics after receiving the same morphine dose. Unlike control or animals pre-treated with saline, subjects prenatally treated with cocaine did not develop CPP with this dose of morphine. Only cocaine-exposed animals showed increased threat, avoidance and fleeing during the social encounter. No differences in motor effects of morphine were observed. Analysis of monoamine…
Acute ammonia toxicity is mediated by the NMDA type of glutamate receptors
1992
AbstractPrevious experiments in our laboratory suggested that ammonium toxicity could be mediated by the NMDA type of glutamate receptors. To assess this hypothesis we tested if MK-801, a specific antagonist of the NMDA receptor, is able to prevent ammonium toxicity. Mice and rats were injected i.p. with 12 and 7 mmol/kg of ammonium acetate, respectively, 73% of the mice and 70% of the rats died. However, when the animals were injected i.p. with 2 mg/kg of MK-801, 15 min before ammonium injection, only 5% of the mice and 15% of the rats died. The remarkable protection afforded by MK-801 indicates that ammonia toxicity is mediated by the NMDA receptor.
Impaired cannabinoid receptor type 1 signaling interferes with stress-coping behavior in mice.
2007
Dysregulation of the endocannabinoid system is known to interfere with emotional processing of stressful events. Here, we studied the role of cannabinoid receptor type 1 (CB1) signaling in stress-coping behaviors using the forced swim test (FST) with repeated exposures. We compared effects of genetic inactivation with pharmacological blockade of CB1 receptors both in male and female mice. In addition, we investigated potential interactions of the endocannabinoid system with monoaminergic and neurotrophin systems of the brain. Naive CB1 receptor-deficient mice (CB1-/-) showed increased passive stress-coping behaviors as compared to wild-type littermates (CB1+/+) in the FST, independent of se…
Neurotensin: dual effect on the motor activity of rat duodenum
1992
The effects of neurotensin on mechanical activity of rat duodenum were investigated using an isometric-isovolumic preparation. Neurotensin (1 pM to 10 nM) induced a concentration-dependent, tetrodotoxin (TTX)-insensitive fall in both endoluminal pressure and isometric tension. At higher concentrations of neurotensin (1 nM to 1 microM) the relaxation was followed by a concentration-dependent TTX-insensitive contraction, detected only by an increase in endoluminal pressure. Different concentrations of neurotensin were required to desensitize the relaxant and the contractile actions of the neuropeptide. The relaxation was antagonized by apamin, while the contractile response was blocked by nif…