Non-associative learning and anxiety in rats treated with a single systemic administration of the gastrin-releasing peptide receptor antagonist RC-3095.

The gastrin-releasing peptide receptor (GRPR) has been implicated in the modulation of emotionally-motivated memory. In the present study, we investigated the role of the GRPR on non-emotional, non-associative memory, and anxiety. Adult male Wistar rats were given a systemic injection of the GRPR antagonist [D-Tpi6, Leu(13) psi(CH2NH)-Leu14] bombesin (6-14) (RC-3095) (0.

Genotoxic, neurotoxic and neuroprotective activities of apomorphine and its oxidized derivative 8-oxo-apomorphine.

Apomorphine is a dopamine receptor agonist proposed to be a neuroprotective agent in the treatment of patients with Parkinson's disease. Both in vivo and in vitro studies have shown that apomorphine displays both antioxidant and pro-oxidant actions, and might have either neuroprotective or neurotoxic effects on the central nervous system. Some of the neurotoxic effects of apomorphine are mediated by its oxidation derivatives.

Reversal of age-related deficits in object recognition memory in rats with l-deprenyl.

The monoamine-oxidase-B (MAO-B) inhibitor l-deprenyl (selegiline) is effective in treating Parkinson's disease and possibly cognitive deficits associated with aging, Alzheimer's disease and HIV dementia. The aim of the present study was to investigate the effects of l-deprenyl on short- and long-term recognition memory in aged rats. Young adult and aged male Wistar rats were trained in a novel object recognition task.

Pro-oxidant action of diphenyl diselenide in the yeast Saccharomyces cerevisiae exposed to ROS-generating conditions.

Organoselenium compounds have a potential thiol peroxidase-like activity. Diphenyl diselenide (DPDS) is an electrophilic reagent used in the synthesis of a variety of pharmacologically active organic selenium compounds. Using TRAP assay of chemiluminescense we have shown that diphenyl diselenide clearly possesses a pro-oxidant property.

Short- and long-term memory are differentialy modulated by hippocampal nerve growth factor and fibroblast growth factor.

Rats were implanted with cannulae in the CA1 area of the dorsal hippocampus and trained in one-trial step-down inhibitory avoidance. Two retention tests were carried out in each animal, one at 1.5 h to measure short-term memory (STM) and another at 24 h to measure long-term memory (LTM).

Dexamethasone reverses the memory impairment induced by antagonism of hippocampal gastrin-releasing peptide receptors.

Storage of emotionally influenced memory is regulated by activation of glucocorticoid receptors (GRs) as well as of gastrin-releasing peptide receptors (GRPRs) in the dorsal hippocampus. In the present study, male Wistar rats were given a bilateral infusion of saline or the GRPR antagonist (D-Tpi6, Leu13 psi[CH2NH]-Leu14) bombesin (6-14) (RC-3095) (1.0 microg/side) into the dorsal hippocampus 10 min before training on an inhibitory avoidance task, followed by an immediate post-training i.

A stable N-heterocyclic carbene with a diboron backbone.

The synthesis of a novel five-membered inorganic ring, a stable N-heterocyclic carbene with a diboron backbone, is reported. A pentacarbonyltungsten complex containing the new carbene is also described. Spectroscopic evidence indicates that the sterically encumbered carbene is a better sigma-donor than classical N-heterocyclic analogues, demonstrating the significant influence of the inorganic backbone on the coordinating properties of the carbon ligand.

Pretraining but not preexposure to the task apparatus prevents the memory impairment induced by blockade of protein synthesis, PKA or MAP kinase in rats.

Adult male Wistar rats were trained and tested in a step-down inhibitory avoidance task (0.4 mA footshock, 24 h training-test interval). Fifteen minutes before or 0, 1.

Differential role of entorhinal and hippocampal nerve growth factor in short- and long-term memory modulation.

We studied the effects of infusion of nerve growth factor (NGF) into the hippocampus and entorhinal cortex of male Wistar rats (250-300 g, N = 11-13 per group) on inhibitory avoidance retention. In order to evaluate the modulation of entorhinal and hippocampal NGF in short- and long-term memory, animals were implanted with cannulae in the CA1 area of the dorsal hippocampus or entorhinal cortex and trained in one-trial step-down inhibitory avoidance (foot shock, 0.4 mA).

Pre- or post-training administration of the NMDA receptor blocker MK-801 impairs object recognition memory in rats.

The aim of the present study was to investigate the effects of NMDA receptor blockade on formation of object recognition memory. In the first experiment, adult Wistar rats were given an intraperitoneal injection of saline or the NMDA receptor antagonist [(+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]cyclo-hepten-5,10-imine-maleate] (MK-801) (0.001, 0.

Genotoxicity of diphenyl diselenide in bacteria and yeast.

Diphenyl diselenide (DPDS) is an electrophilic reagent used in the synthesis of a variety of pharmacologically active organic selenium compounds. This may increase the risk of human exposure to the chemical at the workplace. We have determined its mutagenic potential in the Salmonella/microsome assay and used the yeast Saccharomyces cerevisiae to assay for putative genotoxicity, recombinogenicity and to determine whether DNA damage produced by DPDS is repairable.

Protein synthesis, PKA, and MAP kinase are differentially involved in short- and long-term memory in rats.

We studied the involvement of hippocampal protein synthesis-, PKA-, and MAP kinase-dependent processes in short- (STM) and long-term memory (LTM) for inhibitory avoidance task. Fifteen minutes before or immediately after training rats received intrahippocampal infusions of vehicle, the protein synthesis inhibitor anisomycin, the PKA inhibitor Rp-cAMPs or the MAPKK inhibitor PD098059. The results show that STM recruits PKA and MAPK, whereas, LTM depends on PKA activity and protein synthesis during the early post-training period.

Haloperidol- and clozapine-induced oxidative stress in the rat brain.

Haloperidol (HAL) is a typical neuroleptic that acts primarily as a D2 dopamine receptor antagonist. It has been proposed that reactive oxygen species play a causative role in neurotoxic effects induced by HAL. Adult male Wistar rats received daily injections of HAL (1.

The bombesin/gastrin releasing peptide receptor antagonist RC-3095 blocks apomorphine but not MK-801-induced stereotypy in mice.

Bombesin (BN)-like peptides might be involved in the pathogenesis of neuropsychiatric disorders such as schizophrenia. Stereotyped behaviors induced by the dopamine receptor agonist apomorphine or the N-methyl-D-aspartate glutamate receptor antagonist dizocilpine (MK-801) in rodents have been proposed as animal models of schizophrenic psychosis. In the present study we evaluated the effects of the BN/gastrin-releasing peptide receptor (GRP) antagonist (D-Tpi6, Leu13 psi[CH2NH]-Leu14) bombesin (6-14) (RC-3095) on apomorphine and MK-801-induced stereotyped behavior in mice.

Bombesin/gastrin-releasing peptide receptors in the basolateral amygdala regulate memory consolidation.

Several receptor and intracellular signalling systems in the basolateral amygdala (BLA) regulate memory formation. In the present study, we show that bombesin/gastrin-releasing peptide (GRP) receptors in the BLA are involved in the consolidation of affectively motivated memory. Adult male rats were trained in a single-trial step-down inhibitory avoidance task and tested for retention 24 h later.

RC-3095, a bombesin/gastrin-releasing peptide receptor antagonist, impairs aversive but not recognition memory in rats.

Bombesin and its mammalian equivalent, gastrin-releasing peptide (GRP), stimulate cell proliferation and are involved in the pathogenesis of several types of human cancer. Bombesin-like peptides also display neuroendocrine activities and regulate neural function. In the present study, we evaluated the effects of the bombesin/GRP receptor antagonist (D-Tpi(6), Leu(13) psi[CH(2)NH]-Leu(14)) bombesin-(6-14) (RC-3095), experimental antitumor drug, on memory in rats.

Oxidative damage in brains of mice treated with apomorphine and its oxidized derivative.

Increasing evidence suggests that some of the neurobiological and neurotoxic actions of apomorphine and other dopamine receptor agonists might be mediated by their oxidation derivatives. The aim of the present study was to evaluate the effects of apomorphine and its oxidation derivative, 8-oxo-apomorphine-semiquinone (8-OASQ), on oxidative stress parameters and antioxidant enzyme activity. Adult male CF-1 mice were treated with a systemic injection of apomorphine (0.

[Memory consolidation and posttraumatic stress disorder].

Extensive evidence from animal and human studies has shown that memory formation is enhanced by an endogenous modulatory system mediated by stress hormones and activation of the amygdala. This system is an evolutionarily adaptive method of enhancing important memories. Under emotional stress, this system is activated promoting the formation of vivid, long lasting traumatic memories, which are the hallmark of PTSD.

Intrahippocampal infusion of the bombesin/gastrin-releasing peptide antagonist RC-3095 impairs inhibitory avoidance retention.

Bombesin (BN)-like peptides regulate cell proliferation and cancer growth as well as neuroendocrine and neural functions. We evaluated the effects of the BN/gastrin-releasing peptide (GRP) antagonist RC-3095 on memory formation. Male Wistar rats were given a bilateral infusion of saline or RC-3095 (0.