The selective µ opioid receptor antagonist ß-funaltrexamine attenuates methamphetamine-induced stereotypical biting in mice.

We investigated whether pretreatment with opioid receptor antagonists affected methamphetamine (METH)-induced stereotypy in mice. Pretreatment of male ICR mice with naloxone, a relatively non-selective opioid receptor antagonist, significantly attenuated the total incidence of METH-induced stereotypical behavior compared with saline vehicle-pretreated subjects. Furthermore, the distribution of METH-induced stereotypical behavior was affected by naloxone administration. Thus, METH-induced stereotypical sniffing and persistent locomotion were significantly increased by naloxone treatment while stereotypical biting was reduced. One way to interpret this pattern of effects is that pretreatment with naloxone appeared to produce a shift in the dose-response curve for METH. Thus, while the more intense forms of oral-facial stereotypies were reduced, increased persistent locomotion was observed in mice given naloxone followed by METH. The selective µ opioid receptor antagonist ß-funaltrexamine, but not nor-binaltorphimine (a κ-selective antagonist) nor naltrindole (a δ-selective antagonist), mimicked the effect of naloxone. These observations suggest that opioid receptor antagonists may attenuate METH-induced stereotypical biting in mice via µ opioid receptors, and suggest that antagonism of this system may be a potential therapeutic approach to reducing some deleterious effects of METH use and perhaps in the treatment of some forms of self-injurious behavior.

A single administration of methamphetamine to mice early in the light period decreases running wheel activity observed during the dark period.

Repeated intermittent administration of amphetamines acutely increases appetitive and consummatory aspects of motivated behaviors as well as general activity and exploratory behavior, including voluntary running wheel activity. Subsequently, if the drug is withdrawn, the frequency of these behaviors decreases, which is thought to be indicative of dysphoric symptoms associated with amphetamine withdrawal. Such decreases may be observed after chronic treatment or even after single drug administrations. In the present study, the effect of acute methamphetamine (METH) on running wheel activity, horizontal locomotion, appetitive behavior (food access), and consummatory behavior (food and water intake) was investigated in mice. A multi-configuration behavior apparatus designed to monitor the five behaviors was developed, where combined measures were recorded simultaneously. In the first experiment, naïve male ICR mice showed gradually increasing running wheel activity over three consecutive days after exposure to a running wheel, while mice without a running wheel showed gradually decreasing horizontal locomotion, consistent with running wheel activity being a positively motivated form of natural motor activity. In experiment 2, increased horizontal locomotion and food access, and decreased food intake, were observed for the initial 3h after acute METH challenge. Subsequently, during the dark phase period decreased running wheel activity and horizontal locomotion were observed. The reductions in running wheel activity and horizontal locomotion may be indicative of reduced dopaminergic function, although it remains to be seen if these changes may be more pronounced after more prolonged METH treatments.

Histamine H3 receptor agonists decrease hypothalamic histamine levels and increase stereotypical biting in mice challenged with methamphetamine.

The effects of the histamine H(3) receptor agonists (R)-α-methylhistamine, imetit and immepip on methamphetamine (METH)-induced stereotypical behavior were examined in mice. The administration of METH (10 mg/kg, i.p.) to male ddY mice induced behaviors including persistent locomotion and stereotypical behaviors, which were classified into four categories: stereotypical head-bobbing (1.9%), circling (1.7%), sniffing (14.3%), and biting (82.1%). Pretreatment with (R)-α-methylhistamine (3 and 10 mg/kg, i.p.) significantly decreased stereotypical sniffing, but increased stereotypical biting induced by METH, in a dose-dependent manner. This effect of (R)-α-methylhistamine on behavior was mimicked by imetit or immepip (brain-penetrating selective histamine H(3) receptor agonists; 10 mg/kg, i.p. for each drug). Hypothalamic histamine levels 1 h after METH challenge were significantly increased in mice pretreated with saline. These increases in histamine levels were significantly decreased by pretreatment with histamine H(3) receptor agonists, effects which would appear to underlie the shift from METH-induced stereotypical sniffing to biting.

Withdrawal from fixed-dose injection of methamphetamine decreases cerebral levels of 3-methoxy-4-hydroxyphenylglycol and induces the expression of anxiety-related behavior in mice.

A variety of drug treatment regimens have been proposed to model the dysphoric state observed during methamphetamine (METH) withdrawal in rats, but little has been established in experiments using mice. In male ICR mice, a fixed-dose injection regimen of METH (1.0 or 2.5 mg/kg, i.p., twice daily for 10 consecutive days) induced a significant decrease in the time spent in open arms in an elevated plus maze after 5 days of drug abstinence. Under an escalating-dose injection regimen (0.2-2.0 mg/kg, i.p., 3 times daily for 4 days, total: 15 mg/kg/animal) or continuous subcutaneous administration with osmotic mini-pumps (15 or 76 mg/kg of METH for 2 weeks), no significant behavioral change was observed after 5 days of drug abstinence, compared with control animals. Reduced gains in body weight were observed during repeated treatment with METH in the fixed-dose injection and mini-pump treatment regimens, but not the escalating-dose injection regimen. HPLC analysis revealed significant decreases in the level of cerebral 3-methoxy-4-hydroxyphenylglycol, a norepinephrine metabolite, and norepinephrine turnover, which may be attributed to the expression of anxiety-related behavior in the elevated plus maze. These observations suggest that the mice treated with a fixed-dose of METH may model the anxiety-related behavior observed in the dysphoric state induced by METH withdrawal in humans.

Pretreatment with l-histidine produces a shift from methamphetamine-induced stereotypical biting to persistent locomotion in mice.

The administration of methamphetamine (METH; 10mg/kg, i.p.) to male ICR mice induced bizarre behaviors including persistent locomotion and stereotypical behaviors, which were classified into four categories: stereotypical head-bobbing, circling, sniffing, and biting. Pretreatment with l-histidine (750 mg/kg, i.p.) significantly decreased the stereotypical biting induced by METH and significantly increased persistent locomotion. This effect of l-histidine on behavior was completely abolished by simultaneous administration of pyrilamine or ketotifen (brain-penetrating histamine H(1) receptor antagonists; 10mg/kg each, i.p.), but not by the administration of fexofenadine (a non-sedating histamine H(1) receptor antagonist that does not cross the blood-brain barrier; 20mg/kg), zolantidine (a brain-penetrating histamine H(2) receptor antagonist; 10mg/kg), thioperamide, or clobenpropit (brain-penetrating histamine H(3) receptor antagonists; 10mg/kg each). The histamine content of the hypothalamus was significantly increased by l-histidine treatment. These data suggest that l-histidine modifies the effects of METH through central histamine H(1) receptors.

Dopamine D3 receptor gene polymorphism influences on behavioral and psychological symptoms of dementia (BPSD) in mild dementia of Alzheimer's type.

Dopamine D3 receptor (DRD3) is present in the limbic system, which is thought to regulate affect, cognition, and activity. Thus a functional change in the DRD3 gene could in turn affect the cognitive and psychiatric symptoms of dementia of Alzheimer's type (DAT). We investigated a possible association of DRD3 genotype with DAT and the behavioral and psychological symptoms of dementia (BPSD) in mild DAT. The genotyping for DRD3 and apolipoprotein E (ApoE) was determined using restriction fragment length polymorphism in 210 patients with mild DAT and 224 age- and sex-matched non-demented controls. The occurrence of BPSD during the course of mild dementia was demonstrated using the Behavioral Pathology in Alzheimer's Disease rating scale (BEHAVE-AD). No significant differences in DRD3 genotype were identified between DAT and controls, regardless of ApoE epsilon4. Among the DAT with BPSD, however, a significant association was observed between the presence of the DRD3 glycine allele and paranoid and delusional ideation, regardless of ApoE epsilon4. In conclusion, DRD3 gene polymorphism is unlikely to play a substantial role in conferring susceptibility to DAT, but it may be involved in the development of paranoid and delusional ideation during the course of mild DAT.

Alterations in the levels of heterotrimeric G protein subunits induced by psychostimulants, opiates, barbiturates, and ethanol: Implications for drug dependence, tolerance, and withdrawal.

Neuronal adaptations have been found to occur in multiple brain regions after chronic intake of abused drugs, and are therefore thought to underlie drug dependence, tolerance, and withdrawal. Pathophysiological changes in drug responsiveness as well as behavioral sequelae of chronic drug exposure are thought to depend largely upon the altered state of heterotrimeric GTP binding protein (G protein)-coupled receptor (GPCR)-G protein interactions. Responsiveness of GPCR-related intracellular signaling systems to drugs of abuse is heterogeneous, depending on the types of intracellular effectors to which the specific Galpha protein subtypes are coupled and GPCR-G protein coupling efficiency, factors influenced by the class of drug, expression levels of G protein subunits, and drug treatment regimens. To enhance understanding of the molecular mechanisms that underlie the development of pathophysiological states resulting from chronic intake of abused drugs, this review focuses on alterations in the expression levels of G protein subunits induced by various drugs of abuse. Changes in these mechanisms appear to be specific to particular drugs of abuse, and specific conditions of drug treatment.

IDE Gene Polymorphism Influences on BPSD in Mild Dementia of Alzheimer's Type.

Insulin degrading enzyme (IDE) degrades amyloid beta (Abeta), which may inhibit the accumulation of Abeta in a brain affected with dementia of Alzheimer's type (DAT). A decrease in the activity of IDE results in changes in glucose utilization in the brain, which could affect the cognitive and psychiatric symptoms of DAT. We investigated a possible association of IDE gene polymorphism and the behavioral and psychological symptoms of dementia (BPSD) in mild DAT. The genotyping for IDE and apolipoprotein E (ApoE) was determined in 207 patients with mild DAT and 215 controls. The occurrence of BPSD was demonstrated using the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD). IDE gene polymorphism is unlikely to play a substantial role in conferring susceptibility to DAT, but it may be involved in the development of affective disturbance through the course of mild DAT, regardless of the presence of an ApoE epsilon4 allele. The present data could be the result of a small sample size. Further investigations using larger samples are thus required to clarify the correlation between IDE gene polymorphism, susceptibility to DAT, and emergence of BPSD.

Serotonin transporter gene polymorphism and BPSD in mild Alzheimer's disease.

The purpose of the present study was to confirm an association of functional polymorphism within the serotonin transporter (5-HTT) gene with Alzheimer's disease (AD) and behavioral and psychological symptoms of dementia (BPSD) in mild AD. Apolipoprotein E (ApoE) gene polymorphism and 2 types of functional polymorphism in the 5-HTT gene, 5-HTT-linked polymorphic region (5-HTTLPR) and a 5-HTT variable number of tandem repeats sequence (5-HTTVNTR) were analyzed longitudinally in outpatients with mild AD to find out whether there was a relation between any such polymorphisms and the occurrence of BPSD. No significant differences in genotype distribution or allele frequencies were identified for 5-HTTLPR or 5-HTTVNTR between AD patients and age- and sex-matched non-demented controls regardless of ApoE epsilon4 allele. No significant differences were noted in 5-HTTLPR genotype or allele distributions between AD patients with or without BPSD. However, significant associations were observed between presence of 5-HTTVNTR allele 10 and BPSD or aggressiveness. This difference was independent of the presence of the ApoE epsilon4 allele. As a result, 5-HTT polymorphisms are unlikely to play any substantial role in susceptibility to AD. Conversely, 5-HTTVNTR influences the risk of developing BPSD or aggressiveness and genetic variations in the 5-HTT gene may be involved in the development of symptomatology for mild AD.

Lack of effect of anticonvulsant topiramate on methamphetamine-induced stereotypy and rewarding property in mice.

The effects of topiramate, a structurally novel anticonvulsant, on the methamphetamine (METH)-induced expression of stereotypy and conditioned place preference (CPP) in male ICR mice were investigated. After a single administration of METH (10 mg/kg, i.p.), mice showed stereotyped behaviors with a plateau level 25 min after drug challenge. Pretreatment with topiramate (1, 10, and 100 mg/kg, i.p.) 30 min prior to METH challenge had no effect on the expression frequency of stereotypy, compared with saline challenge. No differential effects of topiramate on METH-induced stereotyped behavior (that is, head-bobbing, circling, continuous sniffing, nail and/or wood-chip biting, and vigorous and compulsive grooming) were observed. In saline-challenged groups, the doses of topiramate examined did not induce any stereotyped behaviors. Although mice showed a significant CPP for METH (0.5 mg/kg, i.p.), pretreatment with subchronic topiramate did not affect the magnitude of CPP. Locomotor activity was not affected by the doses of topiramate tested. Conditioned rewarding or aversive effects of topiramate were not observed as indexed by the place preference procedure. These results suggested the lack of effect of topiramate on METH-induced stereotypy and rewarding property in mice.

IL-18 mediates the formation of stress-induced, histamine-dependent gastric lesions.

A role of IL-18 in the induction of gastric lesions by water immersion and restraint stress (WRS) was investigated. When wild-type BALB/c mice were exposed to WRS, levels of IL-18 in the serum and stomach increased rapidly with the development of acute gastric lesions. In IL-18-deficient mice [IL-18 knockout (KO) mice] similarly exposed to WRS, no gastric lesions were observed, but the administration of IL-18 before exposure to WRS resulted in the induction of WRS-induced gastric lesions. WRS enhanced gastric histidine decarboxylase (HDC) activity with concomitant increases in gastric histamine content. In IL-18 KO mice, the WRS-induced elevation of gastric HDC activity and histamine levels was much less than that in wild-type mice, but it was augmented by prior administration of IL-18. Treatment of wild-type mice with cimetidine, a histamine H2 receptor antagonist, inhibited the formation of WRS-induced gastric lesions with no effect on the induction of gastric IL-18 by WRS. Levels of corticosterone, one of the stress indicators, were lower in IL-18 KO mice than in wild-type mice. The glucocorticoid receptor antagonist mifepristone had no effect on gastric IL-18 and histamine levels but aggravated the stress-induced gastric lesions, indicating that corticosterone was not involved in the IL-18-mediated formation of stress-induced gastric lesions. These results indicate that IL-18 is involved in the induction of gastric lesions by WRS through augmentation of HDC activity and production of histamine in the stomach.

Lobeline attenuates methamphetamine-induced stereotypy in adolescent mice.

In this study, we investigated the effects of lobeline, an alkaloid constituent of Indian tobacco, on methamphetamine (METH)-induced stereotypy in male ICR mice (41-50 days old), an animal model for amphetamine psychosis. After a single administration of METH (10 mg/kg, i.p.), mice showed an initial short-lasting hyperlocomotion and subsequent stereotyped behaviors with a plateau level 25 min after drug challenge. Pretreatment with lobeline (3.0-30 mg/kg, i.p.) 15 min prior to the drug challenge significantly decreased the intensity of stereotypy and increased its latency to onset in a dose-dependent manner, especially 20 min after the drug challenge. In saline challenge groups, the doses of lobeline examined did not affect spontaneous locomotion nor induced any stereotyped behaviors. High-performance liquid chromatography analysis revealed that the range of lobeline doses examined except 30 mg/kg did not affect apparent monoamine turnover in the cerebral cortex, the region of the striatum and nucleus accumbens, and the region of the thalamus and hypothalamus of the mice 20 and 60 min after the drug challenge. These results suggested that the inhibitory effect of lobeline (3.0-10 mg/kg) on METH-induced stereotypy was not attributed to the change in the apparent monoamine turnover.

[Case with probable dementia with Lewy bodies, who shows reduplicative paramnesia and Capgras syndrome].

We report a case of probable dementia with Lewy bodies (DLB), showing reduplicative paramnesia (RP) and Capgras syndrome (CS). The patient, a right-handed 60 year-old male, began to show progressive dementia. At the age of 65, he showed fluctuating cognitive impairment and recurrent visual hallucinations. His SPECT demonstrated hypoperfusion not in the medial temporal cortices, but in the parieto-occipital lobes, where the right hemisphere was dominantly hypoperfused. He was diagnosed with probable DLB. In addition to recurrent visual hallucinations, he showed a sense of self- (or others) transfiguration, consciousness of something non-existent (Leibhaftige Bewusstheit; Jaspers, K.), and fluctuating visuo-spacial impairment. At the age of 67, he gradually complained of his duplicative wives "sosie". Finally he went so far as to talk about a nameless phantom boarder. We considered that RP and CS of this case comprised a sense of self-(or others) transfiguration, misidentification of important persons and places, and productive symptoms such as consciousness of something non-existent (Leibhaftige Bewusstheit) and visual hallucinations. The above mentioned symptoms might be originated not only from the disturbance of visuospacial recognition, which involves the limbic system (especially amygdala), medial frontal cortex, and right hemisphere of the brain, but also from the disturbance of recursive consciousness, due to diffusely damaged brain regions with Lewy body pathology. (Authors' abstract)

Methamphetamine reward in mice as assessed by conditioned place preference test with Supermex sensors: effect of subchronic clorgyline pretreatment.

Recent studies in our laboratory have shown that methamphetamine (METH)-induced hyperlocomotion and behavioral sensitization in mice were inhibited by clorgyline, an irreversible monoamine oxidase inhibitor. In this study, the effect of clorgyline pretreatment on METH-induced rewarding effect was assessed by a conditioned place preference (CPP) test, using an apparatus developed with Supermex sensors (infrared pyroelectric sensors). Although intact male ICR mice showed significant CPP for METH (0.5 mg/kg, i.p.), pretreatment with subchronic clorgyline (0.1 and 10 mg/kg, s.c.) did not affect the magnitude of CPP. At a dose of 1 mg/kg, pretreatment of the mice with clorgyline showed a similar CPP index in both saline/saline and METH/saline pairing groups. During the conditioning session, the mice did not express behavioral sensitization to METH. Pretreatment with clorgyline (0.1, 1, and 10 mg/kg) decreased striatal apparent monoamine turnover in a dose-dependent manner. These results indicated that clorgyline pretreatment (0.1 and 10 mg/kg) did not influence the METH-induced rewarding effect in mice, although pretreatment of the mice with clorgyline at a dose of 1 mg/kg appeared to influence the CPP for METH.

Prepulse inhibition of acoustic startle response in mild cognitive impairment and mild dementia of Alzheimer type.

Amnestic mild cognitive impairment (MCI) describes the condition of memory-impaired individuals who otherwise function well and do not meet the clinical criteria for dementia. Such individuals are considered to represent a transitional stage between normal aging and dementia of Alzheimer type (DAT). Neurobiologic changes in amnestic MCI, and their significance for psychophysiologic function, are poorly understood. In this study, the authors compared acoustic prepulse inhibition (PPI) between subjects with amnestic MCI and mild DAT to characterize sensorimotor gating. The acoustic startle reflex, which the authors measured using an accelerometer and electromyogram, involves whole-body movement and eye blink in response to a sudden loud noise (115 dB). PPI is inhibition of this reflex by a softer noise (prepulse; 85 dB) preceding the startle stimulus by 30 ms. PPI was examined in 30 controls, 20 subjects with amnestic MCI, and 20 subjects with mild DAT. Neither amnestic MCI nor mild DAT affected startle movement amplitude. Subjects with amnestic MCI showed significantly enhanced PPI (gating facilitation), while subjects with mild DAT exhibited significantly less PPI than controls (gating deficit). This pattern of PPI changes suggests that neuropathologic changes in the limbic cortex, mainly the entorhinal cortex, at the earliest stage of DAT might be responsible for PPI abnormalities via disturbed regulation of the limbic cortico-striato-pallido-pontine circuitry. Startle PPI changes could be used as a biologic marker for amnestic MCI and mild DAT.

Effects of monoamine oxidase inhibitors on methamphetamine-induced stereotypy in mice and rats.

In male ICR mice, a single intraperitoneal administration of methamphetamine (METH) (10 mg/kg) induced stereotyped behavior such as continuous sniffing, circling, and nail biting, reaching a plateau level 20 min after the injection. Subcutaneous pretreatment with clorgyline, a monoamine oxidase (MAO)-A inhibitor, at a dose of 0.1 mg/kg 2 h prior to the drug challenge significantly decreased the initial (first 20 min) intensity of stereotypies and increased the latency to onset. The effect was not observed with either higher doses of clorgyline (1 and 10 mg/kg) or l-deprenyl, a MAO-B inhibitor, at doses of 0.1-10 mg/kg. In male Wistar rats, the inhibitory effect of clorgyline on METH-induced stereotypy was not observed. Pretreatment of the mice with clorgyline (0.1 mg/kg) had no effect on apparent serotonin and dopamine turnover in the striatum, although the higher doses of clorgyline (1 and 10 mg/kg) significantly decreased the turnover. These results suggest that a low dose of clorgyline tends to increase the latency and decrease the intensity of stereotypies induced by METH in a dopamine metabolism-independent manner in mice.

Involvement of nucleus accumbens dopaminergic transmission in acoustic startle: observations concerning prepulse inhibition in rats with entorhinal cortex lesions.

The relationship between the entorhinal cortex and prepulse inhibition (PPI) as well as the nucleus accumbens dopaminergic participation in acoustic startle were examined in rats. After the entorhinal cortex was damaged bilaterally using ibotenic acid, a microdialysis probe was placed in the nucleus accumbens for detection of dopamine before, during and after acoustic startle stimuli. In rats with bilateral entorhinal cortex lesions PPI was reduced, and extracellular dopamine in the nucleus accumbens was elevated with or without acoustic stimuli. The entorhinal cortex and the sensorimotor gating system thus may be related via dopaminergic connections in the nucleus accumbens, even though dopamine release did not coincide completely with acoustic startle stimuli.

[Alterations of symptoms with borderline personality disorder after fronto-temporal traumatic brain injury. A case study].

We report a case of borderline personality disorder in which severe self-mutilation, sense of futility and tendency to manipulate others disappeared after fronto (orbital cortex and dorso-lateral surface) temporal traumatic brain injury. The patient, a right-handed 34 year-old woman began having severe depressive moods, irritability, and performed recurrent self-mutilation by wrist cutting after her marriage at age 20. She was diagnosed as having borderline personality disorder. At the age of 30, she attempted to kill herself by leaping from a building, and sustained a frontotemporal traumatic brain injury. After 5 years of follow-up, she recovered from Wernicke's-like aphasia, but could not understand anything complex. She also showed disturbances of writing, calculating, attention, working memory, recent and remote memories, motivation, and sense of self. The results of tests of higher brain function were as follows: Wisconsin card sorting test (Keio version), C = 1, D = 2, P = 23; FAB (Frontal Assessment Battery) = 7/18; Trail making test B = impossible. Brain MRI demonstrated left frontal lobe (orbital cortex and dorso-lateral surface) contusions, severe atrophy in the left temporal cortex including the hippocampus and amygdala, and diffuse axonal injury in the left frontal white matter. Although her recurrent self-mutilation had disappeared after brain injury, a certain type of anxiety, which occasionally induced irritability, unstable moods and devaluation of others, occurred without any trigger once or twice a month. This anxiety continued two or three days and faded away within a week. Because of its frequency and duration, this anxiety can be considered to originate not from the traumatic brain injury, but from her intrinsic nature, and seems to be parallel to annihilation anxiety (Reich A, Klein M) and abandonment anxiety (DSM-IV). Because she showed this anxiety after a severe higher brain dysfunction including disturbances of language, attention, working memory, recent and remote memories, motivation, and sense of self, we considered this anxiety to be an unarticulated form of annihilation anxiety and abandonment anxiety.