SEARCH · Search PubMed

Results for “GABA Modulators”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,603 records · Page 89Linked to original sources

PubMed2006

Benzodiazepines for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a disfiguring movement disorder, often of the orofacial region, frequently caused by the use of neuroleptic drugs. A wide range of strategies have been used to help manage tardive dyskinesia, and for those who are unable to have their antipsychotic medication stopped or substantially changed, the benzodiazepine group of drugs have been suggested as a useful adjunctive treatment. OBJECTIVES: To determine the effects of benzodiazepines for neuroleptic-induced tardive dyskinesia in people with schizophrenia or other chronic mental illnesses. SEARCH STRATEGY: 1. Electronic searches. For the update of 2006, we searched The Cochrane Schizophrenia Group Trials Register (November 2005). For the previous two updates (1996, 2002) the review authors searched Biological Abstracts (1982-2002), the Cochrane Schizophrenia Group's Register of trials (February 2002), EMBASE (1980-2002), LILACS (1982-2002), MEDLINE (1966-2002), PsycLIT (1974-2002), SCISEARCH (2002), hand searched references of all included/excluded studies and contacted the first author of each included trial. SELECTION CRITERIA: We included all randomised clinical studies focusing on people with schizophrenia (or other chronic mental illnesses) and neuroleptic-induced tardive dyskinesia that compared benzodiazepines with placebo or no intervention. DATA COLLECTION AND ANALYSIS: We independently extracted data from the studies and ensured that they were reliably selected, and quality assessed. For homogenous dichotomous data we calculated random effects, relative risk (RR), 95% confidence intervals (CI) and, where appropriate, numbers needed to treat (NNT) on an intention-to-treat basis. We synthesised continuous data from valid scales by using a weighted mean difference (WMD). For continuous outcomes we preferred endpoint data to change data. MAIN RESULTS: We identified three trials (total N=56, one additional trial since 2002, n=24). Using benzodiazepines as an adjunctive treatment did not result in any clear changes for a series of tardive dyskinesia medium-term outcomes (n=30, 2 RCTs, RR not improved to clinically important extent 1.08 CI 0.57 to 2.05). One trial (n=24) found end point abnormal movement scores to be better for those receiving adjunct benzodiazepines(WMD AIMS -3.22 CI -4.63 to -1.81 ). Less than 10% in both groups left these studies before completion and none of the studies reported clear adverse effects. AUTHORS' CONCLUSIONS: One small study reports some preliminary evidence that benzodiazepines may have some effect in neuroleptic induced tardive dyskinesia. Inconclusive results from other studies means routine clinical use is not indicated and these treatments remain experimental.

Anti-Anxiety Agents↗

PubMed2002

Insular cortex involvement in mesiotemporal lobe epilepsy: a positron emission tomography study.

Somesthetic and emotional symptoms that are common in patients with mesial temporal lobe epilepsy are usually related to hippocampo-amygdalar complex involvement. Recent stereo-electroencephalographic studies have shown a relationship between such symptoms and epileptic insular discharges. To further investigate this problem, we carried out a positron emission tomography study using fluorodeoxyglucose (18F-FDG) and flumazenil (11C-FMZ) in mesial temporal lobe epilepsy patients. The aim of our study was to assess the existence of a cortical insular involvement in order to examine its clinical correlates and the relationship between the postoperative outcome and the insular involvement. Fluorodeoxyglucose and flumazenil-positron emission tomography studies were carried out in 18 patients with mesial temporal lobe epilepsy patients. A statistical parametric mapping (SPM96) was performed to analyze the data in comparison to 18 healthy volunteers. For each set of fluorodeoxyglucose and flumazenil images a group and an individual analysis were performed. In addition, a region of interest analysis was performed to validate the results. Focusing on the metabolic abnormalities, we also investigated the role of insular cortex in the symptoms experienced by the patients and the prognostic value of insular metabolic abnormalities. Highly significant hypometabolism and BZR binding decreases were detected in the insular cortex. Results were similar using the region of interest approach. Insular involvement (mainly ipsilateral to the seizure focus) was present in 60% of the patients. Emotional symptoms correlated with hypometabolism in the anterior part of the ipsilateral insular cortex, whereas somesthetic symptoms correlated with hypometabolism in the posterior part. No relationship between postoperative outcome and ipsilateral insular hypometabolism was found. Unilateral mesial temporal lobe epilepsy is associated with insular hypometabolism and benzodiazepine receptor loss. Our results also suggest that the anterior part of the insular cortex is involved in the emotional symptoms and the posterior insular cortex is involved in the somesthetic symptoms. Hypometabolism located in the insula did not influence postoperative outcome after anterior lobectomy.

Adolescent↗

PubMed2003

Seizure exacerbation associated with inhibition of progesterone metabolism.

The reduced progesterone metabolite tetrahydroprogesterone is a potent positive modulator of GABA(A) chloride conductance that exerts powerful neuroinhibitiory and anti-seizure effects in animal models. Cyclic natural progesterone use may lessen seizure frequency in women with catamenial seizure exacerbation. We report a case in which efficacy was eliminated during concomitant treatment with a reductase inhibitor. The observation suggests that a reduced metabolite, rather than progesterone itself, was responsible for improved seizure control.

Adult↗

PubMed1988

Gamma-aminobutyric acid in the medial rat nucleus accumbens: ultrastructural localization in neurons receiving monosynaptic input from catecholaminergic afferents.

Neurons containing gamma-aminobutyric acid (GABA) in the medial portion of the adult rat nucleus accumbens were characterized with respect to their ultrastructure, sites of termination, and catecholaminergic input. Antisera against GABA-conjugates and the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), were localized within single sections by means of peroxidase-antiperoxidase (PAP) and immunoautoradiographic labeling methods. Peroxidase reaction product indicating GABA-like immunoreactivity (GABA-LI) was seen in medium-size (15-20 microns) perikarya containing either round and unindented or invaginated nuclear membranes. The cells with invaginated nuclei were few in number and usually exhibited more intense peroxidase reaction product in sections collected at the same distance from the surface of the tissue. Reaction product for GABA was also detected in proximal (1.5-3.0 microns) dendrites, axons, and terminals. Terminals with GABA-LI formed symmetric junctions on perikarya, proximal dendrites, and dendritic spines of neurons that usually lacked detectable immunoreactivity. Many of the GABAergic terminals also were apposed directly to other unlabeled terminals and to terminals exhibiting either peroxidase labeling for GABA or immunoautoradiographic labeling for TH. Many of the unlabeled terminals associated with the GABAergic axons formed asymmetric junctions on dendritic spines. From 138 TH-labeled, principally dopaminergic terminals that were examined in the medial nucleus accumbens, 4% were associated with the somata of GABAergic neurons and another 14% formed symmetric junctions with proximal dendrite showing GABA-LI. The remaining TH-immuno-reactive terminals either lacked recognizable densities or formed symmetric synapses on unlabeled dendrites and spines. A few of the unlabeled dendrites, as well as those containing GABA-LI, received symmetric synapses from both catecholaminergic and GABAergic terminals. We conclude that in the medial portion of the rat nucleus accumbens, GABA is localized to two morphologically distinct types of neurons, one or both of which receive monosynaptic input from catecholaminergic afferents, and that GABAergic terminals form symmetric synapses on other principally non-GABAergic neurons. The results also support earlier physiological evidence showing that GABA may modulate the output of other GABAergic and non-GABAergic neurons through presynaptic associations.

Animals↗

PubMed2002

Panic disorder patients at the time of air strikes.

We assessed the impact of real danger on several aspects of the panic disorder (PD) patients' psychopathology and level of disability. At the time of the NATO air strikes on Belgrade, 84 PD patients who were in partial or complete remission were administered the Panic and Agoraphobia Scale (PAS). All had been treated previously, and the majority (58.3%) were taking antipanic medications. The PAS, which was used as part of the regular follow-up assessment battery for PD patients, measures the overall severity of PD and the severity of key aspects and components of PD. Compared to the PAS assessments made before the onset of air strikes, the PAS assessments made at the time of air strikes showed significant differences in terms of decreased overall severity of PD, fewer health concerns, decrease in the level of disability, and greater intensity and frequency of anticipatory anxiety. Differences on the measures of panic attacks and agoraphobic avoidance were negligible. These results suggest that there is no relationship between panic attacks and real danger and lend support to the notion that panic attacks and fear induced by real danger are different phenomena. Contrary to the expectations of many PD patients, the presence of real danger does not seem to be associated with deterioration in their functioning, and PD patients can be reassured that they are not likely to cope worse under conditions of danger.

Adult↗

PubMed2003

Pharmacological treatment of social anxiety disorder: a meta-analysis.

Placebo-controlled trials have evaluated the efficacy of several medications in the treatment of social anxiety disorder but information regarding their relative efficacy is lacking. We compared the efficacy of medications systematically studied for the treatment of social anxiety disorder using meta-analytic techniques. The methodology included a database search of articles published between January 1980 and June 2001 and manual searches of bibliographies in published manuscripts. Trials were included if they reported outcome data on the Liebowitz Social Anxiety Scale (LSAS) or a categorical measure of responder status. Data were extracted independently by two authors. The Q statistic was used to assess homogeneity across trials. All analyses were conducted using intent-to-treat data. There was substantial heterogeneity across trials. The medications with largest effect sizes were phenelzine [effect size, 1.02; 95% Confidence Interval (CI), 0.52-1.52], clonazepam (effect size, 0.97; 95% CI, 0.49-1.45), gabapentin (effect size, 0.78; 95% CI, 0.29-1.27), brofaromine (effect size, 0.66; 95% CI, 0.38-0.94), and the selective serotonin reuptake inhibitors (SSRIs; effect size, 0.65; 95% CI, 0.50-0.81). There were no statistically significant differences between medications or medication groups. However, formal methods of interim monitoring adapted for meta-analyses suggested strongest evidence of efficacy for SSRIs and brofaromine. Several medications are efficacious for the treatment of social anxiety disorder. The stability of the SSRI effect size estimate in conjunction with other evidence for safety and tolerability and their ability to treat comorbid conditions supports the use of SSRIs as the first-line treatment. Direct comparisons of SSRIs vs. other promising medications deserve consideration.

Acetates↗

PubMed2004

Enhancement of GABA-related signalling is associated with increase of functional connectivity in human cortex.

Structural or operational synchrony analysis with EEG was conducted in order to detect functional interaction between cortical areas during an enhanced inhibition induced by the GABAergic agonist lorazepam in a double-blind, randomized, placebo-controlled, cross-over study in eight healthy human subjects. Specifically, we investigated whether a neuronal inhibitory system in the brain mediates functional decoupling of cortical areas. Single-dose lorazepam administration resulted in a widespread increase in the inter-area functional connectivity and an increase in the strength of functional long-range and interhemispheric connections. These results suggest that inhibition can be an efficient mechanism for synchronization of large neuronal populations.

Adult↗

PubMed1998

Flumazenil for hepatic encephalopathy grade III and IVa in patients with cirrhosis: an Italian multicenter double-blind, placebo-controlled, cross-over study.

The rationale for use of benzodiazepine receptor antagonists is based on the so-called benzodiazepine pathogenetic hypothesis of hepatic encephalopathy (HE). To assess the efficacy of flumazenil, a specific benzodiazepine receptor antagonist, in a large and selected population of cirrhotic patients with severe HE, we conducted a double-blind, placebo-controlled, cross-over trial on 527 cirrhotic patients with HE grade III and IVa admitted to Intensive Care Units over a 5-year period; among them, 265 (132 of grade III and 133 of grade IVa) received flumazenil, whereas 262 (130 of grade III and 132 of grade IVa) received placebo. Treatment was begun within 15 minutes of randomization; the response to treatment was assessed by neurological score and by continuous electroencephalographic (EEG) recordings. Improvement of the neurological score was documented in 17.5% of grade III patients treated with flumazenil and in 14.7% of grade IVa patients, compared, respectively, with 3.8% and 2.7% of the patients of both groups treated with placebo. Improvements in EEG tracings were observed in 27.8% of grade III patients and in 21.5% of grade IVa patients, compared, respectively, with 5% and 3.3% of the patients of both groups treated with placebo. Benzodiazepines were detected in the serum of 10 patients (4 in grade III group and 6 in grade IVa group). Flumazenil is beneficial only in a selected subset of cirrhotic patients with severe HE; the applicability of this treatment to unselected patients with severe HE still remains to be determined.

Adult↗

PubMed2003

Multiple hypothalamic sites control the frequency of hippocampal theta rhythm.

Stimulation of a neural pathway originating in the brainstem reticular formation, with synapses in the medial hypothalamus, activates the hippocampal theta rhythm. The frequency of reticular-elicited theta is determined in the medial supramammillary nucleus (mSuM) completely in anaesthetised rats, but only partially when the animal is awake. We tested other medial hypothalamic sites for their capacity to control theta frequency in awake rats. Blockade of sodium channels (1 microl fast infusion of the local anaesthetic procaine, experiment 1) or increased inhibition by GABA (Chlordiazepoxide [CDP], experiment 2) was found to reduce or increase the frequency of reticular-elicited theta, depending on the precise site of injection, in the region of the dorsomedial hypothalamic nucleus (DMH) and the posterior hypothalamic nucleus (PH). A band of null sites for CDP was located in the region of the ventral border of PH and dorsal border of mSuM. Using 0.5 and 1 microl CDP, and slow infusions (experiment 3), it was found that effective PH sites were also separate from mSuM in the rostrocaudal direction. In experiment 4, the DMH/PH region was mapped with unilateral and bilateral slow infusions of 0.5 microl CDP. CDP significantly reduced frequency in medial (periventricular) and dorsal PH, but not DMH. Bilateral injections appeared to generally sum the usual effects of unilateral injection, producing effects of intermediate size. However, the absolute frequency change in any given site, or with any pair of sites, did not exceed 1 Hz, which is similar to what is seen with single injections in mSuM. Overall, it appears that at, any one time, theta frequency may be determined by a complex interplay between distinct but interacting modulatory regions in the medial hypothalamus.

Action Potentials↗

PubMed2007

Possible predictors of response to clonazepam augmentation therapy in patients with protracted depression.

INTRODUCTION: Clonazepam has been shown to be an effective supplementary treatment for depression. Thus, it would be useful to determine which patient characteristics are associated with response to clonazepam. AIMS: The purpose of this study was to examine the possible predictors of response to clonazepam in the treatment of depression. METHOD: A retrospective cohort analysis was carried out in 120 patients with protracted depression who were being treated with clonazepam. RESULTS: A variety of clinical factors, including age, gender, type of depression, frequency of episodes, family history; and daily dose of clonazepam, were analyzed as possible predictors of response to clonazepam. A Weibull regression analysis showed that the factors that best predicted improvement with clonazepam augmentation were negative family history of psychiatric illness (e(coef) = 0.378), daily clonazepam dose of 2.5-4.0 mg (e(coef) = 0.160), and unipolar depression (e(coef) = 0.147). CONCLUSIONS: These factors should be considered when clonazepam augmentation therapy is selected for protracted depression.

Adult↗

PubMed2002

Extended action of MKC-242, a selective 5-HT(1A) receptor agonist, on light-induced Per gene expression in the suprachiasmatic nucleus in mice.

We reported previously that (S)-5-[3-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3-benzodioxole hydrochloride (MKC-242) (3 mg kg(-1), i.p.), a selective 5-HT(1A) receptor agonist, accelerated the re-entrainment of hamster wheel-running rhythms to a new 8 hr delayed or advanced light-dark cycle, and also potentiated the phase advance of the wheel-running rhythm produced by light pulses. The molecular mechanism underlying MKC-242-induced potentiation of this phase shift, however, has not yet been elucidated. We examined the effects of MKC-242 on light-induced mPer1 and mPer2 mRNA expression in the suprachiasmatic nucleus (SCN) of mice. MKC-242 (5 mg kg(-1), i.p.) potentiated light-induced mPer1 and mPer2 expression in the SCN of mice housed in constant darkness for 2 days, when mRNA levels were observed 3 hr after light-exposure. More potentiating action of MKC-242 on mPer2 expression in the SCN was observed in mice housed in constant darkness for 9-10 days. This facilitatory action of MKC-242 on mPer1 expression was antagonized by WAY100635, a selective 5-HT(1A) receptor blocker, indicating that MKC-242 activated 5-HT(1A) receptors. Other drugs such as 8-hydroxy-dipropylaminotetralin (10 mg kg(-1), i.p.), paroxetine (10 mg kg(-1), i.p.), buspirone (10 mg kg(-1), i.p.), and diazepam (10 mg kg(-1), i.p.) did not display a potentiating action on light-induced mPer1 and mPer2 expression in the SCN. In the behavioral experiments, we found that MKC-242 (5 mg kg(-1), i.p.) potentiated light-induced phase delays of free-running rhythm in mice. The present results suggest that prolonged increase of mPer1 or mPer2 expression in the SCN by MKC-242 may be involved in the potentiation of photic entrainment by MKC-242 in mice.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed2006

Ultra-fast absorption of amorphous pure drug aerosols via deep lung inhalation.

A deficiency of most current drug products for treatment of acute conditions is slow onset of action. A promising means of accelerating drug action is through rapid systemic drug administration via deep lung inhalation. The speed of pulmonary drug absorption depends on the site of aerosol deposition within the lung and the dissolution rate and drug content of the deposited particles. Alveolar delivery of fast-dissolving, pure drug particles should in theory enable very rapid absorption. We have previously shown that heating of thin drug films generates vapor-phase drug that subsequently cools and condenses into pure drug particles of optimal size for alveolar delivery. Here we present a hand held, disposable, breath-actuated device incorporating this thermal aerosol technology, and its application to the delivery of alprazolam, an anti-panic agent, and prochlorperazine, an anti-emetic with recently discovered anti-migraine properties. Thermal aerosol particles of these drugs exist in an amorphous state, which results in remarkably rapid drug absorption from the lung into the systemic circulation, with peak left ventricular concentrations achieved within 20 s, even quicker than following rapid (5 s) intravenous infusion. Absorption of the thermal aerosol is nearly complete, with >80% absolute bioavailability found in both dogs and human normal volunteers.

Absorption↗

PubMed2004

Dystonia in the Mohr-Tranebjaerg syndrome responds to GABAergic substances.

Mutations in the X-linked deafness-dystonia peptide 1 (DDP1) gene cause Mohr-Tranebjaerg syndrome (MTS), a rare form of deafness associated with dystonia. In the patient presented here, improvement of dystonic symptoms upon treatment with alcohol and GABAergic substances is demonstrated for the first time.

Adult↗

PubMed1997

Action palatal tremor in a patient with primary intestinal lymphoma.

We report the case of a 59-year-old man with primary intestinal T-cell non-Hodgkin's lymphoma who developed abnormal facial twitching synchronous with small palatal movements induced by attempts at speaking or swallowing. At rest, the electromyogram (EMG) showed no spontaneous muscular activity. Phonation triggered trains of synchronous, rhythmic EMG bursts at a frequency of 3-4 Hz lasting 10-20 s, with an average burst of 150 ms, which simultaneously involved palatal, facial, and neck muscles bilaterally with left-sided predominance. An enhanced blink reflex recovery curve was observed after stimulation of either side. Backaveraging electroencephalographic study revealed no activity that was time locked with the jerks. Axial T2-weighted magnetic resonance imaging showed an increased signal intensity and bilateral enlargement of the inferior olives. No antineuronal-specific antibodies were found in the blood or in the cerebrospinal fluid. All of these clinical findings were consistent with a symptomatic palatal tremor (PT). Because it was triggered by activation of cranial muscles, we termed this movement disorder action PT. To our knowledge, this is the first report of symptomatic PT displaying these features.

Blinking↗

PubMed1998

Is speech arrest during wada testing a valid method for determining hemispheric representation of language?

BACKGROUND AND OBJECTIVE: The intracarotid amobarbital procedure, or Wada test, is the method of choice to determine hemispheric representation of language, and is routinely used in the presurgical evaluation for intractable epilepsy. Some investigators perform comprehensive language assessments, but others base language lateralization solely on speech arrest. This study sought to determine whether speech arrest alone during Wada testing provides valid data regarding language lateralization. METHODS: The subjects (previously reported) were 21 patients evaluated for intractable epilepsy, who underwent language lateralization by Wada testing and functional MRI (FMRI). For each patient, language representation was determined by calculating: (1) a Wada laterality index based exclusively on speech arrest; (2) a Wada laterality index based on comprehensive language assessment; and (3) an FMRI laterality quotient. Correlation coefficients and categorical classifications were analyzed. RESULTS: There was no significant correlation between the Wada laterality quotient derived from duration of speech arrest and either the comprehensive Wada language laterality score (r =.35, p =.12) or FMRI language laterality score (r =.32, p =.16). Categorical classification as left, right or bilateral language also showed marked discordance between speech arrest and the other two methods. CONCLUSION: Duration of speech arrest during Wada testing is not a valid measure of language dominance.

Amobarbital↗

PubMed2002

The Mallory body as an aggresome: in vitro studies.

Prior in vivo studies supported the concept that Mallory bodies (MBs) are aggresomes of cytokeratins 8 and 18. However, to test this hypothesis an in vitro model is needed to study the dynamics of MB formation. Such a study is difficult because MBs have never been induced in tissue culture. Therefore, MBs were first induced in vivo in drug-primed mice and then primary cultures of hepatocytes from these mice were studied. Two approaches were utilized: 1. Primary cultures were transfected with plasmids containing the sequence for cytokeratin 18 (CK 18) tagged with green fluorescent protein (GFP). 2. Immunofluorescent staining was used to localize the ubiquitin-proteasome pathway components involved in MB-aggresome complex formation in primary hepatocyte cultures. The cells were double stained with a ubiquitin antibody and one of the following antibodies: CK 8, CK 18, tubulin, mutant ubiquitin (UBB+1), transglutaminase, phosphothreonine, and the 20S and 26S proteasome subunits P25 and Tbp7, respectively. In the first approach, fluorescence was observed in keratin filaments and MBs 48 h after the cells were transfected with the CK 18 GFP plasmid. Nascent cytokeratin 18 was preferentially concentrated in MBs. Less fluorescence was observed in the normal keratin filaments. This indicated that MBs continued to form in vitro. The immunofluorescent staining of the hepatocytes showed that CK 8 and 18, ubiquitin, mutant ubiquitin (UBB+1), P25, Tbp7, phosphothreonine, tubulin, and transglutaminase were all located at the border or the interior of the MB. These results support the concept that MBs are aggresomes of CK 8 and CK18 and are a result of inhibition of the ubiquitin-proteasome pathway of protein degradation possibly caused by UBB+1.

Animals↗

PubMed1997

Effect of piperonyl butoxide on cell replication and xenobiotic metabolism in the livers of CD-1 mice and F344 rats.

Male CD- 1 mice were fed diets containing 0 (control), 10, 30, 100, and 300 mg/kg/day piperonyl butoxide (PBO) and 0.05% sodium phenobarbital (NaPB) and male F344 rats were fed diets containing 0 (control), 100, 550, 1050, and 1850 mg/kg/day PBO and 0.5% NaPB for periods of 7 and 42 days. In both species PBO and NaPB increased relative liver weight and whereas PBO produced a midzonal (mouse) or periportal/midzonal (rat) hypertrophy, NaPB produced a centrilobular hypertrophy. In the rat, individual cell necrosis was also observed at 42 days after high doses of PBO. Replicative DNA synthesis, assessed as the hepatocyte labeling index following implantation of 7-day osmotic pumps containing 5-bromo-2'-deoxyuridine during Study Days 0-7 and 35-42, was increased in mice given 300 mg/kg/day PBO and NaPB for 7 days and in rats given 550 and 1050 mg/kg/day PBO and NaPB for 7 days and 1050 mg/kg/day PBO for 42 days. While PBO had no effect on body weights in mice, the body weights of rats given 550, 1050, and 1850 mg/kg/day PBO for 42 days were reduced to 92, 89, and 70% of control, respectively. PBO induced microsomal cytochrome P450 content and mixed function oxidase activities in the mouse and rat, although the effects were less marked than those produced by NaPB. In summary, this data demonstrates that PBO can produce liver enlargement in the mouse and the rat which is associated with induction of xenobiotic metabolism, hypertrophy, and hyperplasia. The hepatic effects of PBO in the mouse were similar to but less marked than those produced by NaPB. In the rat high doses of PBO were hepatotoxic and resulted in a marked reduction in body weight. Thus while the reported formation of eosinophilic nodules in mouse liver by PBO may occur by a mechanism(s) similar to that of NaPB and other nongenotoxic enzyme inducers, the reported tumor formation in rats at greater than the maximum tolerated dose is most likely associated with marked enzyme induction in conjunction with a regenerative hyperplasia resulting from PBO-induced hepatotoxicity.

Administration, Oral↗

PubMed1995

Distinct profile of working memory errors following acute or chronic disruption of the cholinergic septohippocampal pathway.

The behavioral effects of two amnestic treatments (intraseptal chlordiazepoxide (CDP) and intraventricular AF64A) were examined in a delayed-nonmatch-to-sample radial-arm maze (DNMTS) paradigm. The types of errors induced by these treatments in this working memory task were assessed to determine how acute and chronic disruptions of the medial septum affect different phases of working memory (encoding, maintenance, retrieval). Rats were initially trained to perform the DNMTS task with a 1-h delay imposed between the training and the testing sessions. The first experiment demonstrated that intraseptal injection of 30 nmoles of CDP did not produce state-dependent learning. Rats were injected immediately following training with CDP or artificial cerobrospinal fluid (CSF; drug vehicle) and then prior to testing with CDP or CSF. Injection of CDP immediately following training (CDP-CSF) impaired performance of the task regardless of whether CDP was also administered before the postdelay test (CDP-CDP). Rats infused with CDP only before the postdelay test (CSF-CDP) exhibited a proactive deficit characterized by intact retention of the predelay information (i.e., arms entered prior to the delay) but impaired performance on the postdelay component (arms entered only after the delay). These data indicate: (i) that state dependency does not explain the working memory deficits induced by intraseptal CDP; (ii) that pretest CDP disrupts the storage and utilization of working memory for current arm selections. The second experiment examined the behavioral effects induced by a permanent disruption of the cholinergic septohippocampal pathway produced by icv injection of the cholinotoxin AF64A. Rats were initially trained on the DNMTS task and then bilaterally injected icv with either AF64A (2.5 nmoles/side) or CSF. AF64A-treated rats exhibited a significant impairment of performance compared to CSF-treated controls. In contrast to the impairment exhibited by CDP-treated rats in Experiment 1, the performance of AF64A-treated rats displayed a deficit in the maintenance/retrieval of information acquired during RAM training and an impairment in ability to store current spatial information in working memory to guide postdelay testing performance. These studies demonstrate that acute and chronic disruptions of the septohippocampal pathway produce distinct profiles of cognitive impairment that should help to reveal the behavioral and neurobiological characteristics of spatial memory.

Animals↗