Life Sciences Commons^™

Whole Egg Consumption Impairs Insulin Sensitivity In Rat Model Of Obesity And Type 2 Diabetes, Cassondra J. Saande, Megan A. Steffes, Joseph L. Webb, Rudy J. Valentine, Matthew J. Rowling, Kevin Schalinske

Rudy Valentine

Background: The literature regarding the relation between egg consumption and type 2 diabetes (T2D) is inconsistent and there is limited evidence pertaining to the impact of egg consumption on measures of insulin sensitivity. Objective: The objective of this study was to investigate the effect of dietary whole egg on metabolic biomarkers of insulin resistance in T2D rats. Downloaded from https://academic.oup.com/cdn/advance-article-abstract/doi/10.1093/cdn/nzz015/5374517 by Iowa State University user on 28 March 2019 Methods: Male Zucker diabetic fatty rats (n=12; 6 wk of age) and their lean controls (n=12; 6 wk of age) were randomly assigned to a casein- or whole egg-based diet. At …

Computer Vision Evidence Supporting Craniometric Alignment Of Rat Brain Atlases To Streamline Expert-Guided, First-Order Migration Of Hypothalamic Spatial Datasets Related To Behavioral Control, Arshad M. Khan, Jose G. Perez, Claire E. Wells, Olac Fuentes

Arshad M. Khan, Ph.D.

Predicting Human Drug Toxicity And Safety Via Animal Tests: Can Any One Species Predict Drug Toxicity In Any Other, And Do Monkeys Help?, Jarrod Bailey, Michelle Thew, Michael Balls

Jarrod Bailey, PhD

Animals are still widely used in drug development and safety tests, despite evidence for their lack of predictive value. In this regard, we recently showed, by producing Likelihood Ratios (LRs) for an extensive data set of over 3,000 drugs with both animal and human data, that the absence of toxicity in animals provides little or virtually no evidential weight that adverse drug reactions will also be absent in humans. While our analyses suggest that the presence of toxicity in one species may sometimes add evidential weight for risk of toxicity in another, the LRs are extremely inconsistent, varying substantially for …

An Analysis Of The Use Of Animal Models In Predicting Human Toxicology And Drug Safety, Jarrod Bailey, Michelle Thew, Michael Balls

Jarrod Bailey, PhD

Animal use continues to be central to preclinical drug development, in spite of a lack of its demonstrable validity. The current nadir of new drug approvals and the drying-up of pipelines may be a direct consequence of this. To estimate the evidential weight given by animal data to the probability that a new drug may be toxic to humans, we have calculated Likelihood Ratios (LRs) for an extensive data set of 2,366 drugs, for which both animal and human data are available, including tissue-level effects and MedDRA Level 1–4 biomedical observations. This was done for three preclinical species (rat, mouse …

Insular Cortex Lesions And Morphine-Induced Suppression Of Conditioned Stimulus Intake In The Rat, Christopher T. Roman, Steve Reilly

Christopher Roman

The present experiment examined the influence of insular cortex (IC) lesions on the intake of a taste stimulus in a consummatory procedure that used morphine as the unconditioned stimulus. In normal rats, morphine caused a rapid reduction in saccharin intake when the taste was novel but not when it was familiar. Irrespective of stimulus novelty, morphine had little influence on the saccharin consumption of IC-lesioned rats. The results are discussed in terms of a lesion-induced disruption of (i) a reward comparison mechanism and (ii) the perception of taste novelty.

Taste, Olfactory And Trigeminal Neophobia In Rats With Forebrain Lesions, Jian-You Lin, Christopher T. Roman, Justin St. Andre, Steve Reilly

Christopher Roman

The present study was designed to examine whether lesions of the insular cortex (IC; Experiment 1), the basolateral amygdala (BLA) or medial amygdala (MeA; Experiment 2) influence the neophobic reactions to orally consumed liquid stimuli. Three different types of stimuli were used: taste (0.5% saccharin), olfactory (0.1% amyl acetate), and trigeminal (0.01 mM capsaicin). Rats with IC, BLA and MeA lesions showed normal responses to the olfactory and trigeminal stimuli. Each type of lesion, however, disrupted the initial occurrence of neophobia to the taste stimulus. The significance of these findings to conditioned taste aversion is discussed.

Taste-Potentiated Odor Aversion Learning In Rats With Lesions Of The Insular Cortex, Jian-You Lin, Christopher T. Roman, Steve Reilly

Christopher Roman

The current study assessed the influence of excitotoxic lesions of the insular cortex (IC) on tastepotentiated odor aversion (TPOA) learning. Water-deprived rats initially received a single odortoxicosis or odor/taste-toxicosis pairing and were subsequently tested, in separate trials, with the odor and the taste stimulus. Indicating TPOA, neurologically intact rats conditioned with the odor/taste compound stimulus acquired significantly stronger odor aversions than normal rats conditioned with the odor stimulus. IC lesions disrupted TPOA, conditioned taste aversion and taste neophobia. The finding that taste did not potentiate odor aversion learning in the IC lesioned rats provides support for the “within-compound association” analysis …

Taste Neophobia And C-Fos Expression In The Rat Brain, Jian-You Lin, Christopher T. Roman, Joe Arthurs, Steve Reilly

Christopher Roman

Taste neophobia refers to a reduction in consumption of a novel taste relative to when it is familiar. To gain more understanding of the neural basis of this phenomenon, the current study examined whether a novel taste (0.5% saccharin) supports a different pattern of c-Fos expression than the same taste when it is familiar. Results revealed that the taste of the novel saccharin solution evoked more Fos immunoreactivity than the familiar taste of saccharin in the basolateral region of the amygdala, central nucleus of the amygdala, gustatory portion of the thalamus, and the gustatory insular cortex. No such differential expression …

Effects Of Insular Cortex Lesions On Conditioned Taste Aversion And Latent Inhibition In The Rat, Christopher T. Roman, Steve Reilly

Christopher Roman

The present study tested the hypothesis that lesions of the insular cortex of the rat retard the acquisition of conditioned taste aversions (CTAs) because of an impairment in the detection of the novelty of taste stimuli. Demonstrating the expected latent inhibition effect, nonlesioned control subjects acquired CTAs more rapidly when the conditioned stimulus (0.15% sodium saccharin) was novel rather than familiar (achieved by pre-exposure to the to-be-conditioned taste cue). However, rats with insular cortex lesions acquired taste aversions at the same slow rate regardless of whether the saccharin was novel or familiar. The pattern of behavioural deficits obtained cannot be …

Morphine-Induced Suppression Of Conditioned Stimulus Intake: Effects Of Stimulus Type And Insular Cortex Lesions, Jian-You Lin, Christopher T. Roman, Steve Reilly

Christopher Roman

Intake of an unconditionally preferred taste stimulus (e.g., saccharin) is reduced by contingent administration of a drug of abuse (e.g., morphine). We examined the influence of insular cortex (IC) lesions on morphine-induced suppression of an olfactory cue and two taste stimuli with different levels of perceived innate reward value. Two major findings emerged from this study. First, morphine suppressed intake of an aqueous odor as well as each taste stimulus in neurologically intact rats. Second, IC lesions disrupted morphine-induced suppression of the taste stimuli but not the aqueous odor cue. These results indicate that the perceived innate reward value of …

Basolateral Amygdala And Morphine-Induced Taste Avoidance In The Rat, Jamie Lovaglio, Jian-You Lin, Christopher T. Roman, Steve Reilly

Christopher Roman

The present experiment examined the influence of excitotoxic lesions of the basolateral amygdala (BLA) on morphine-induced saccharin avoidance. Neurologically intact subjects rapidly learned to avoid drinking the taste conditioned stimulus (CS), an effect that was sustained throughout the experiment. Although the BLA-lesioned (BLAX) rats showed CS avoidance over the first few trials, the effect was not sustained. That is, by the end of the experiment, the BLAX rats were drinking the same amount of saccharin after seven saccharin-morphine trials as they did on the first trial (i.e., prior to the morphine injections). Potential interpretations of the results are discussed including …

Conditioned Taste Aversion And Latent Inhibition Following Extensive Taste Preexposure In Rats With Insular Cortex Lesions, Christopher T. Roman, Jian-You Lin, Steve Reilly

Christopher Roman

Lesions of the insular cortex (IC) attenuate acquisition of conditioned taste aversions (CTAs). We have suggested that this impairment is the expected consequence of a failure of IC-lesioned (ICX) rats to recognize unfamiliar taste stimuli as novel. That is, ICX rats treat novel taste stimuli as if they are familiar and as a result show a latent inhibition-like retardation of learning. This account anticipates that ICX rats should acquire CTAs at the same slow rate as normal rats that are familiar with the taste stimulus. The present experiment confirmed this hypothesis in a design that compared CTA acquisition in normal …

Can Acute Dermal Systemic Toxicity Tests Be Replaced With Oral Tests? A Comparison Of Route-Specific Systemic Toxicity And Hazard Classifications Under The Globally Harmonized System Of Classification And Labelling Of Chemicals (Ghs), Nigel P. Moore, David J. Andrew, Donald L. Bjerke, Stuart Creton, David Dreher, Thomas Holmes, Pilar Prieto, Troy Seidle, Tim G. Rowan

Troy Seidle, PhD

Acute systemic toxicity data (LD50 values) and hazard classifications derived in the rat following oral administration and dermal application have been analysed to examine whether or not orally-derived hazard classification or LD50 values can be used to determine dermal hazard classification. Comparing the oral and dermal classifications for 335 substances derived from oral and dermal LD50 values respectively revealed 17% concordance, and indicated that 7% of substances would be classified less severely while 76% would be classified more severely if oral classifications were applied directly to the dermal route. In contrast, applying the oral LD50 values within the dermal classification …

Variations In Radial Maze Performance Under Different Levels Of Food And Water Deprivation, Robert H.I. Dale, William A. Roberts

Robert H. I. Dale

Four groups of rats were tested on an eight-arm radial maze under a free-choice procedure. The subjects were maintained at either 80% or 100% of their preexperimental free-feeding weights through restricted access to either food or water. Water-deprived subjects received water in the maze; food-deprived subjects received food. Water-deprived subjects learned the task faster than food-deprived subjects. The four groups developed different response patterns. These were measured by the mean transition size, the average angular distance (in 45° units) between consecutively chosen arms. Rats foraging for food and water developed different search strategies, with water-deprived subjects exhibiting lower mean transition …

Radial-Maze Performance In The Rat Following Lesions Of Posterior Neocortex, Melvyn A. Goodale, Robert H.I. Dale

Robert H. I. Dale

The present experiment was designed to investigate the role of posterior neocortex (areas 17, 18 and 18a) in the maintenance of performance on the radial maze. Following training to criterion on the 8-arm radial maze, rats received either sham operations, bilateral eye enucleations, lesions of posterior neocortex, or combined enucleations and lesions of posterior neocortex. While the enucleated animals with intact brains showed a slight, but significant performance decrement relative to the sham-operated group, the other two groups, with lesions of areas 17, 18 and 18a, each showed a massive deficit. This large deficit was observed even in the group …

Parallel-Arm Maze Performance Of Sighted And Blind Rats: Spatial Memory And Maze Structure, Robert H.I. Dale

Robert H. I. Dale

Sighted and peripherally blinded groups of rats learned to obtain a small reward from each arm of an eight-arm parallel maze, and a sighted group was similarly trained on a radial maze. The parallel-sighted and parallel-blind groups were equally slow, and much slower than the radial-sighted group, to attain criterion performance. The three groups shared several response characteristics: selectively avoiding the most recently entered arms, frequently choosing adjacent arms, and an absence of 'spatial generalization' among the arms. The findings support a simple model proposing how subjects identify and choose among the maze-arms.

Interactions Between Response Stereotypy And Memory Strategies On The Eight-Arm Radial Maze, Robert H.I. Dale, Nancy K. Innis

Robert H. I. Dale

Three groups of water-deprived rats collected water from the ends of the 8 arms of an 8-arm radial maze. Sighted subjects, and subjects blinded either with or without pre-enucleation experience on the radial maze, all retrieved the water efficiently. Most of the subjects exhibited the same response stereotypy, regularly choosing 8 adjacent arms of the maze, then stopping in the center of the maze. The strategies underlying this performance were analyzed by interrupting trials and rotating the maze 180° after the subject had made 3 choices. Sighted subjects depended on extramaze stimuli, naive-blind subjects depended on intramaze stimuli and experienced-blind …

Effects Of Simvastatin And 6-Hydroxydopamine Lesion On Histaminergic H1 Receptor Binding In Rat Brains, C H. Hu, C Deng, Xu-Feng Huang, J Chen, Q Wang

Xu-Feng Huang

No abstract provided.

Perinatal Exposure To Polychlorinated Biphenyls Alters Social Behaviors In Rats, Howard C. Cromwell

Howard Casey Cromwell

Perinatal exposure to polychlorinated biphenyls (PCBs) leads to significant alterations of neural and hormonal systems. These alterations have been shown to impair motor and sensory development. Less is known about the influence of PCB exposure on developing emotional and motivational systems involved in social interactions and social learning. The present study examined the impact of perinatal PCB exposure (mixture of congeners 47 and 77) on social recognition in juvenile animals, conspecific-directed investigation in adults and on neural and hormonal systems involved in social functions. We used a standard habituation–dishabituation paradigm to evaluate juvenile recognition and a social port paradigm to …

Pathological Alterations In Gabaergic Interneurons And Reduced Tonic Inhibition In The Basolateral Amygdala During Epileptogenesis, Michael A. Rogawski, Brita Fritsch, Felicia Qashu, T. H. Figueiredo, Vicki Aroniadou-Anderjaska, Maria F.M. Braga

Michael A. Rogawski

An acute brain insult such as traumatic head/brain injury, stroke, or an episode of status epilepticus can trigger epileptogenesis, which, after a latent, seizure-free period, leads to epilepsy. The discovery of effective pharmacological interventions that can prevent the development of epilepsy requires knowledge of the alterations that occur during epileptogenesis in brain regions that play a central role in the induction and expression of epilepsy. In the present study, we investigated pathological alterations in GABAergic interneurons in the rat basolateral amygdala (BLA), and the functional impact of these alterations on inhibitory synaptic transmission, on days 7 to 10 after status …