Executive functions of postweaning protein malnutrition in mice.

It is well known that nutritional status during the fetal and/or lactation period is important for the development of the central nervous system (CNS). In contrast, the effect of malnutrition on postweaning development has not yet been thoroughly investigated. In the present study, we analyzed the behavioral and neuroanatomical effects of protein malnutrition (PM) postweaning in mice.

Pharmacological characterizations of memantine-induced disruption of prepulse inhibition of the acoustic startle response in mice: involvement of dopamine D2 and 5-HT2A receptors.

It has recently been reported that psychotic symptoms in patients such as those with Parkinson's disease dementia (PDD) and Lewy body dementia (LBD) may worsen following treatment with memantine, a non-competitive NMDA receptor antagonist. Prepulse inhibition (PPI) of the acoustic startle response (ASR) is used as a measure for sensorimotor gating and it has been reported that PPI is disrupted by memantine. However, the mechanism of memantine-induced PPI disruption remains unclear.

Influence of olfactory bulbectomy on maternal behavior and dopaminergic function in nucleus accumbens in mice.

Olfactory bulbectomy (OBX) induces behavioral, physiological, and neurochemical alterations resembling clinical depression and is widely used as an animal model of depression. It has been reported that depression is a critical cause of child abuse and neglect and that maternal behavior involves dopaminergic neurons of the mesolimbic pathway. In a previous study we found that OBX mice show maternal behavior deficits which are improved by administration of apomorphine, a non-selective dopamine agonist.

p-Hydroxyamphetamine causes prepulse inhibition disruptions in mice: contribution of dopamine neurotransmission.

It is well known that amphetamine induces disrupted prepulse inhibition (PPI) in humans and rodents. We have previously reported that intracerebroventricular (i.c.

Effects of atomoxetine on levels of monoamines and related substances in discrete brain regions in mice intermittently deprived of rapid eye movement sleep.

An imbalance between noradrenergic and dopaminergic systems is implicated in hyperactivity disorders, such as attention deficit/hyperactivity disorder (ADHD). We previously showed that the explosive jumping behavior elicited by intermittent rapid eye movement sleep deprivation (REMSD) may serve as a useful model of ADHD (see [Biogenic Amines, 20, 99-111]). Here, we investigated whether intermittent REMSD might cause changes in monoamine turnover in the mouse forebrain.

Effect of non-selective dopaminergic receptor agonist on disrupted maternal behavior in olfactory bulbectomized mice.

Olfactory bulbectomy (OBX) animals are considered a putative model of depression that produces behavioral, physiological, and neurochemical alterations resembling clinical depression. Depression is a critical cause of child abuse and neglect, and it has been reported that maternal behavior involves dopaminergic neurons of the mesolimbic pathway. In this study, we investigated the effect of apomorphine, a non-selective dopaminergic receptor agonist, on maternal behavior to examine the influence of activated brain dopaminergic function in OBX mice.

Suppressive effects by cysteine protease inhibitors on naloxone-precipitated withdrawal jumping in morphine-dependent mice.

The effects of various protease inhibitors on naloxone-precipitated withdrawal jumping were examined in morphine-dependent mice. The doses of morphine were subcutaneously given twice daily for 2 days (day 1, 30 mg/kg; day 2, 60 mg/kg). On day 3, naloxone (8 mg/kg) was intraperitoneally administered 3h after final injection of morphine (60 mg/kg), and the number of jumping was immediately recorded for 20 min.

Central administration of p-hydroxyamphetamine produces a behavioral stimulant effect in rodents: evidence for the involvement of dopaminergic systems.

Rationale And Objectives: It is well-known that amphetamine induces increased locomotor activity in rodents. We previously found that intracerebroventricular (i.c.

Nociceptive behavior induced by the endogenous opioid peptides dynorphins in uninjured mice: evidence with intrathecal N-ethylmaleimide inhibiting dynorphin degradation.

Dynorphins, the endogenous opioid peptides derived from prodynorphin may participate not only in the inhibition, but also in facilitation of spinal nociceptive transmission. However, the mechanism of pronociceptive dynorphin actions, and the comparative potential of prodynorphin processing products to induce these actions were not fully elucidated. In our studies, we examined pronociceptive effects of prodynorphin fragments dynorphins A and B and big dynorphin consisting of dynorphins A and B, and focused on the mechanisms underlying these effects.

Subchronic stress-induced depressive behavior in ovariectomized mice.

Aims: Mood disorders including depression are more common in women than men, particularly in times of lower estradiol levels. In this study, we investigated the effect of estrogen on emotional behavior in mice in a stress environment.

Main Methods: Female mice were divided into four groups: two groups were ovariectomized (OVX) and two were sham-operated.

Involvement of the p53 tumor-suppressor protein in the development of antinociceptive tolerance to morphine.

The present study was designed to determine whether the p53 tumor-suppressor protein is involved in the development of antinociceptive tolerance to morphine. When the doses of morphine (mg/kg per injection) were subcutaneously given into mice as pretreatment twice daily for 2 days (first day (30) and second day (60)), intrathecal (i.t.

Cysteine protease inhibitors suppress the development of tolerance to morphine antinociception.

The effects of various protease inhibitors on the development of antinociceptive tolerance to morphine were examined in mice. Intrathecal (i.t.

Intrathecally administered D-cycloserine produces nociceptive behavior through the activation of N-methyl-D-aspartate receptor ion-channel complex acting on the glycine recognition site.

Intrathecal (i.t.) administration of D-cycloserine (100 and 300 fmol), a partial agonist of the glycine recognition site on the N-methyl-D-aspartate (NMDA) receptor ion-channel complex, produced a behavioral response mainly consisting of biting and/or licking of the hindpaw and the tail along with slight hindlimb scratching directed toward the flank in mice, which peaked at 5 - 10 min and almost disappeared at 15 min after the injection.

Preventive effect of kami-untan-to on performance in the forced swimming test in thiamine-deficient mice: relationship to functions of catecholaminergic neurons.

The kampo (Japanese herbal) medicine "kami-untan-to" (KUT) has been used for a long time in the treatment of neuropsychiatric disorders. We have recently reported that mice put on a thiamine-deficient (TD) diet exhibit a depressive behavior and impairment in avoidance learning after 20 days, and that this impairment was reversed by the chronic administration of KUT. In the present study, we investigated the effect of KUT on the depressive behavior observed in TD mice by using the forced swimming test.

S-(+)-fenfluramine-induced nociceptive behavior in mice: Involvement of interactions between spinal serotonin and substance P systems.

Intrathecal (i.t.) administration into mice of S-(+)-fenfluramine (0.

Anti-inflammatory effect of propolis through inhibition of nitric oxide production on carrageenin-induced mouse paw edema.

The anti-inflammatory effect of propolis was compared with that of diclofenac, a non-steroidal anti-inflammatory drug, and L-N(G)-nitro arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, using carrageenin-induced mouse paw edema. When administered 10 min prior to carrageenin injection, propolis (1 : 1000, 1 : 100, p.o.

Differential effects of N-peptidyl-O-acyl hydroxylamines on dynorphin-induced antinociception in the mouse capsaicin test.

In the capsaicin test, intrathecal (i.t.) dynorphins are antinociceptive.

Alterations in cognitive function in prepubertal mice with protein malnutrition: relationship to changes in choline acetyltransferase.

We have found that protein malnutrition (PM) causes a significant impairment of memory-related behavior on the 15th and 20th day after the start of PM (5% casein) feeding in prepubertal mice but not in postpubertal mice, as measured by a passive-avoidance task. This impairment was almost completely reversed by merely switching to a standard protein (20% casein) diet on the 10th day after the start of PM. However, the reversal was not observed when the switching to a standard protein regimen was done on the 15th day of the PM diet.

Pronociceptive role of dynorphins in uninjured animals: N-ethylmaleimide-induced nociceptive behavior mediated through inhibition of dynorphin degradation.

Intrathecal (i.t.) administration into mice of N-ethylmaleimide (NEM), a cysteine protease inhibitor, produced a characteristic behavioral response, the biting and/or licking of the hindpaw and the tail along with slight hindlimb scratching directed toward the flank.

Nociceptive behavior induced by poly-L-lysine and other basic compounds involves the spinal NMDA receptors.

We have previously shown that spermine, a basic polyamine, and big dynorphin, a basic polypeptide, induce nociceptive behavior if injected intrathecally (i.t.) in mice (see [Pain 86 (2000) 55-61] and [Brain Res.

Development of tolerance to the inhibitory effect of loperamide on gastrointestinal transit in mice.

The inhibitory effect of repetitiously administered loperamide, a peripheral mu-opioid receptor agonist and well-recognized antidiarrheal agent, on mouse gastrointestinal transit was compared with that of morphine in order to examine the development of tolerance to mu-opioid receptor agonist-induced constipation (antitransit effect). When administered subcutaneously 15 min before the oral injection of charcoal meal, loperamide (0.1-30 mg/kg) and morphine (1-8 mg/kg) dose-dependently and significantly inhibited gastrointestinal transit of charcoal with the ID(50) values of 1.

Immunohistochemical fluorescence intensity reduction of brain somatostatin in the impairment of learning and memory-related behaviour induced by olfactory bulbectomy.

The role of brain somatostatin (SST) on memory function after olfactory bulbectomy (OBX) was investigated by using the passive-avoidance task and immunohistochemical analyses in mice. The present study indicated that the learning and memory-related behaviour was impaired on the 7th and 14th day, but not on the 1st day after OBX. The impairment of learning and memory-related behaviour on the 14th day after OBX was dose-dependently reversed by intracerebroventricularly administered SST (1 microg per mouse).

Effect of nutritive and tonic crude drugs on physical fatigue-induced stress models in mice.

The present study was undertaken to investigate the acute anti-fatigue effect of a liquid nutritive and tonic crude drugs (NTDs) on stress induced in mice. After forced walking for 3 or 6h, the NTDs (applied orally, 10 ml/kg) significantly increased locomotor activity, while the administration of NTDs after rapid eye movement (REM) sleep deprivation stress and after immobilization stress did not show a specific effect, having a similar effect as the vehicle with added vitamins, taurine and caffeine. The administration of NTDs after freezing due to electric shock stress showed a specific effect which was not seen in other control groups, water, vehicle (ethanol) and vehicle including vitamins, taurine and caffeine and so resemble the specific effect of NTDs in the stress of forced walking.

Characteristics of changes in cholinergic function and impairment of learning and memory-related behavior induced by olfactory bulbectomy.

Memory function after olfactory bulbectomy (OBX) was examined in two tasks, namely, step-through passive avoidance task and elevated plus-maze task. OBX mice showed a significant impairment of learning and memory-related behavior on the 7th and 14th day, as measured by passive avoidance task but not elevated plus maze task. The impairment of learning and memory-related behavior on the 14th day was improved by administration of the cholinesterase inhibitor physostigmine (0.

Intrathecally administered big dynorphin, a prodynorphin-derived peptide, produces nociceptive behavior through an N-methyl-D-aspartate receptor mechanism.

Intrathecal (i.t.) administration of big dynorphin (1-10 fmol), a prodynorphin-derived peptide consisting of dynorphin A and dynorphin B, to mice produced a characteristic behavioral response, the biting and/or licking of the hindpaw and the tail along with slight hindlimb scratching directed toward the flank, which peaked at 5-15 min after an injection.