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A Review Of Rat Lungworm Infection And Recent Data On Its Definitive Hosts In Hawaii, Chris Niebuhr, Susan I. Jarvi, Shane R. Siers Oct 2019

A Review Of Rat Lungworm Infection And Recent Data On Its Definitive Hosts In Hawaii, Chris Niebuhr, Susan I. Jarvi, Shane R. Siers

USDA Wildlife Services: Staff Publications

Rat lungworm (Angiostrongylus cantonensis) is a zoonotic nematode that causes rat lungworm disease (angiostrongyliasis), a potentially debilitating form of meningitis, in humans worldwide. The definitive hosts for rat lungworm are primarily members of the genus Rattus, with gastropods as intermediate hosts. This parasite has emerged as an important public health concern in the United States, especially in Hawaii, where the number of human cases has increased in the last decade. Here we discuss the current knowledge of the rat lungworm, including information on the life cycle and host species, as well as updates on known infection levels. Three species of …


Neuroanatomical Substrates Of The Disruptive Effect Of Olanzapine On Rat Maternal Behavior As Revealed By C-Fos Immunoreactivity, Changjiu Zhao, Ming Li Dec 2012

Neuroanatomical Substrates Of The Disruptive Effect Of Olanzapine On Rat Maternal Behavior As Revealed By C-Fos Immunoreactivity, Changjiu Zhao, Ming Li

Department of Psychology: Faculty Publications

Olanzapine is one of the most widely prescribed atypical antipsychotic drugs in the treatment of schizophrenia. Besides its well-known side effect on weight gain, it may also impair human parental behavior. In this study, we took a preclinical approach to examine the behavioral effects of olanzapine on rat maternal behavior and investigated the associated neural basis using the c-Fos immunohistochemistry. On postpartum Days 6–8, Sprague-Dawley mother rats were given a single injection of sterile water or olanzapine (1.0, 3.0 or 5.0 mg/kg, sc). Maternal behavior was tested 2 h later, after which rats were sacrificed and brain tissues were collected. …


Drug–Drug Conditioning Between Citalopram And Haloperidol Or Olanzapine In A Conditioned Avoidance Response Model: Implications For Polypharmacy In Schizophrenia, Nathan L. Sparkman, Ming Li Oct 2012

Drug–Drug Conditioning Between Citalopram And Haloperidol Or Olanzapine In A Conditioned Avoidance Response Model: Implications For Polypharmacy In Schizophrenia, Nathan L. Sparkman, Ming Li

Department of Psychology: Faculty Publications

Patients with schizophrenia often have anxiety and depression, and thus are treated with multiple psychotherapeutic medications. This practice of polypharmacy increases the possibility for drug–drug interactions. However, the pharmacological and behavioral mechanisms underlying drug–drug interactions in schizophrenia remain poorly understood. In the present study, we adopted a preclinical approach and examined a less known behavioral mechanism, drug–drug conditioning (DDC) between haloperidol (a typical antipsychotic) or olanzapine (atypical antipsychotic) and citalopram (a selective serotonin reuptake inhibitor). A rat two-way conditioned avoidance response paradigm was used to measure antipsychotic activity and determine how DDC may alter the antipsychotic efficacy in this model. …


Parametric Studies Of Antipsychotic-Induced Sensitization In The Conditioned Avoidance Response Model: Roles Of Number Of Drug Exposure, Drug Dose, And Test–Retest Interval, Natashia Swalve, Ming Li Aug 2012

Parametric Studies Of Antipsychotic-Induced Sensitization In The Conditioned Avoidance Response Model: Roles Of Number Of Drug Exposure, Drug Dose, And Test–Retest Interval, Natashia Swalve, Ming Li

Department of Psychology: Faculty Publications

Repeated haloperidol and olanzapine treatment produces an enhanced disruption of avoidance responding, a validated measure of antipsychotic activity. Experimental parameters affecting this sensitization-like effect have not been thoroughly examined. The present study investigated the role of three parameters (number of injections, dose, and interval between initial exposure and challenge) in antipsychotic sensitization in the conditioned avoidance response paradigm. Well-trained Sprague–Dawley rats received different numbers of drug treatment (1–5 days) or different doses of haloperidol (0.025–0.10 mg/kg, subcutaneously) or olanzapine (0.5–2.0 mg/kg, subcutaneously). After certain time intervals (4, 10 or 17 days), they were tested for the expression of haloperidol or …


Differential Effects Of Acute Amphetamine And Phencyclidine Treatment And Withdrawal From Repeated Amphetamine Or Phencyclidine Treatment On Social Interaction And Social Memory In Rats, Ming Li, Wei He, Rebecca Munro Jan 2012

Differential Effects Of Acute Amphetamine And Phencyclidine Treatment And Withdrawal From Repeated Amphetamine Or Phencyclidine Treatment On Social Interaction And Social Memory In Rats, Ming Li, Wei He, Rebecca Munro

Department of Psychology: Faculty Publications

Although animal models based on amphetamine (AMPH) or phencyclidine (PCP) treatment have been used extensively to study the neurobiological and behavioral characteristics of schizophrenia, there are conflicting reports regarding their validity in modeling the negative symptoms and cognitive deficits of schizophrenia. The present study examined how acute AMPH or PCP treatment (Experiment 1) and withdrawal from repeated AMPH treatment (Experiment 2) or PCP treatment (Experiment 3) affects social behavior and social recognition memory in male Sprague-Dawley rats. Each subject was tested on two consecutive days. On the first day, the rats were tested four times (5 min/each) at 10-min intervals …


Contextual And Behavioral Control Of Antipsychotic Sensitization Induced By Haloperidol And Olanzapine, Chen Zhang, Ming Li Jan 2012

Contextual And Behavioral Control Of Antipsychotic Sensitization Induced By Haloperidol And Olanzapine, Chen Zhang, Ming Li

Department of Psychology: Faculty Publications

Repeated administration of haloperidol (HAL) and olanzapine (OLZ) causes a progressively enhanced disruption of the conditioned avoidance response (CAR) and a progressively enhanced inhibition of phencyclidine (PCP)-induced hyperlocomotion in rats (termed antipsychotic sensitization). Both actions are thought to reflect intrinsic antipsychotic activity. The present study examined the extent to which antipsychotic- induced sensitization in one model (e.g. CAR) can be transferred or maintained in another (e.g. PCP hyperlocomotion) as a means of investigating the contextual and behavioral controls of antipsychotic sensitization. Well-trained male Sprague-Dawley rats were first repeatedly tested in the CAR or the PCP (3.2 mg/kg, subcutaneously) hyperlocomotion model …


Olanzapine And Risperidone Disrupt Conditioned Avoidance Responding In Phencyclidine-Pretreated Or Amphetamine-Pretreated Rats By Selectively Weakening Motivational Salience Of Conditioned Stimulus, Ming Li, Wei He, Alexa Mead Feb 2009

Olanzapine And Risperidone Disrupt Conditioned Avoidance Responding In Phencyclidine-Pretreated Or Amphetamine-Pretreated Rats By Selectively Weakening Motivational Salience Of Conditioned Stimulus, Ming Li, Wei He, Alexa Mead

Department of Psychology: Faculty Publications

The rat conditioned avoidance response model is a well-established preclinical behavioral model predictive of antipsychotic efficacy. All clinically approved antipsychotic drugs disrupt conditioned avoidance responding – a feature that distinguishes them from other psychotherapeutics. We previously showed that the typical antipsychotic drug haloperidol disrupts avoidance responding by progressively attenuating the motivational salience of the conditioned stimulus (CS) in normal rats. In this study, using two pharmacological rat models of schizophrenia [e.g. phencyclidine (PCP) or amphetamine sensitization], we examined whether atypicals such as olanzapine or risperidone disrupt avoidance responding through the same behavioral mechanism. Rats were first pretreated with PCP, amphetamine, …


An Investigation Of The Behavioral Mechanisms Of Antipsychotic Action Using A Drug-Drug Conditioning Paradigm, Ming Li, Wei He, Alexa Mead Jan 2009

An Investigation Of The Behavioral Mechanisms Of Antipsychotic Action Using A Drug-Drug Conditioning Paradigm, Ming Li, Wei He, Alexa Mead

Department of Psychology: Faculty Publications

Antipsychotic drugs at noncataleptic doses selectively suppress conditioned avoidance response in rats. In our previous study, we had used a two-way active avoidance response paradigm to show that the antipsychotic-induced interoceptive state is one of the mechanisms underlying the avoidance-disruptive effect of antipsychotics. In this study, we sought to further examine this mechanism using a novel drug-drug conditioning procedure. We made use of the fact that both the typical neuroleptic haloperidol and the atypical neuroleptic olanzapine disrupt conditioned avoidance responding, whereas chlordiazepoxide (an anxiolytic) does not. We reasoned that if the antipsychotic interoceptive state is important in causing a disruption …


Amphetamine Selectively Enhances Avoidance Responding To A Less Salient Stimulus In Rats, Ming Li, Wei He, Rebecca Munro Jan 2008

Amphetamine Selectively Enhances Avoidance Responding To A Less Salient Stimulus In Rats, Ming Li, Wei He, Rebecca Munro

Department of Psychology: Faculty Publications

This preclinical study examined the psychological processes affected by amphetamine that contribute to human psychosis. Using a novel avoidance conditioning paradigm involving two conditioned stimuli (CS) with varied salience, we found that acute amphetamine (1.5 mg/ kg, i.p.) selectively enhanced avoidance responding to a less salient stimulus, but not to a salient one. These findings suggest that elevated dopaminergic activity selectively enhances the attributions of motivational salience to a less salient stimulus, a process that may bear relevance to the development of human delusional thoughts.


Nicotine Serves As A Feature-Positive Modulator Of Pavlovian Appetitive Conditioning In Rats, M. I. Palmatier, J. L. Peterson, J. L. Wilkinson, Rick A. Bevins Sep 2004

Nicotine Serves As A Feature-Positive Modulator Of Pavlovian Appetitive Conditioning In Rats, M. I. Palmatier, J. L. Peterson, J. L. Wilkinson, Rick A. Bevins

Department of Psychology: Faculty Publications

The present experiments examined whether a nicotine state could set the occasion for a pairing between visual cues and a rewarding outcome in rats. Following nicotine administration, presentation of a conditional stimulus (CS; light-on) was followed by brief access to a sucrose solution. When saline was administered, the same CS was presented but was not followed by any consequence. In Experiment 1, two groups assessed whether rats could acquire this Pavlovian feature-positive discrimination via different training procedures. An anticipatory food-seeking conditioned response (CR) developed during the CS on nicotine sessions but not on saline sessions in both groups. In Experiment …


Individual Differences In Behavioral Responses To Novelty And Amphetamine Self-Administration In Male And Female Rats, J. E. Klebaur, Rick A. Bevins, T. M. Segar, M. T. Bardo Dec 2001

Individual Differences In Behavioral Responses To Novelty And Amphetamine Self-Administration In Male And Female Rats, J. E. Klebaur, Rick A. Bevins, T. M. Segar, M. T. Bardo

Department of Psychology: Faculty Publications

Previous work has shown that individual differences in locomotor activity in an inescapable novel environment can predict acquisition of amphetamine self-administration. The current study examined whether individual differences in approach to novelty in a free choice test could also predict amphetamine self-administration. Further, the current study examined whether individual differences in either free choice or inescapable novelty tests could predict responding for a nondrug reinforcer (sucrose) in the presence and absence of amphetamine. Male and female rats were first tested for their response to free choice novelty (playground maze and novelty-induced place preference tests) and inescapable novelty. They were then …


Nicotine Enhances Acquisition Of A T-Maze Visual Discrimination: Assessment Of Individual Differences, J. Besheer, Rick A. Bevins Nov 2000

Nicotine Enhances Acquisition Of A T-Maze Visual Discrimination: Assessment Of Individual Differences, J. Besheer, Rick A. Bevins

Department of Psychology: Faculty Publications

In the present report, rats' performance was assessed in five tasks designed to measure behavioral response to different novel stimuli under different experimental situations. Daily nicotine treatment (0, 0.3 or l.0 mg/kg) began after the conclusion of the behavioral tasks and continued throughout the experiment. Training of a T-maze visual discrimination task commenced after 11 days of nicotine pretreatment. As a group, rats treated with the higher dose of nicotine (l.0 mg/kg) made fewer errors to acquire the initial T-maze discrimination than saline-treated controls. Activity induced by an inescapable novel environment (i.e. first behavioral screen) was positively correlated with the …


Individual Differences In Response To Novelty, Amphetamine-Induced Activity And Drug Discrimination In Rats, Rick A. Bevins, J. E. Klebaur, M. T. Bardo Mar 1997

Individual Differences In Response To Novelty, Amphetamine-Induced Activity And Drug Discrimination In Rats, Rick A. Bevins, J. E. Klebaur, M. T. Bardo

Department of Psychology: Faculty Publications

Rats mere pre-tested in several individual difference screens - novelty-induced activity, novelty-induced place preference, novel-object interaction, and amphetamine-induced activity. Rats that were more sensitive to the locomotor effects of amphetamine were more active in an inescapable novel environment and displayed a greater preference for a novel environment. All animals were then trained to discriminate amphetamine (1 mg/kg) from saline in a two-bar discrimination procedure using food-maintained responding. After acquisition of the discrimination (mean =37 trials), two amphetamine generalization tests (0.0625,0.125,0.25,0.5, 1.0 and 2.0 mg/kg) were conducted. In the second generalization test, rats that were more sensitive to the activating effect …