Behavioral Neurobiology Commons^™

Regaining Effort-Based Food Motivation: The Drug Methylphenidate Reverses The Depressive Effects Of Tetrabenazine In Female Rats, Deanna Pietrorazio

Honors Scholar Theses

Tetrabenazine (TBZ), a vesicular monoamine transporter type 2 (VMAT-2) inhibitor, depletes dopamine and induces motivational deficits and other depressive symptoms in humans. Methylphenidate (MPH) is a dopamine transport blocker that is used to enhance motivational function. Previous studies have shown that in male rats, TBZ induces a shift in effort-related choice such that a low-effort bias is induced. In male rats this occurs at a dose range of 0.75-1.0 mg/kg TBZ, and this effect is reversible with co-administration of MPH. Recent studies have shown that females need a higher dose of TBZ (2.0 mg/kg) to show the low-effort bias. The …

Long-Term Impacts Of Acute Stressor Exposure On Locus Coeruleus Function And Anxiety-Like Behavior In Rats, Olga Borodovitsyna

Graduate School of Biomedical Sciences Theses and Dissertations

Stress is a physiological state characterized by behavioral arousal that occurs during exposure to harmful or threatening stimuli, and usually facilitates an adaptive behavioral response. The persistence of stress sometimes causes it to become maladaptive, potentially contributing to disease development, including physiological complications with altered neuroendocrine signaling and impaired function of organ systems, and psychological conditions including depression and anxiety. Anxiety disorders in particular are associated with a history of stress and are the most common class of mental disorders, with a lifetime prevalence of 33.7% in the general population. The locus coeruleus (LC) is a major node in the …

Effects Of Repeated Intermittent Episodes Of Social Stress On The Acquisition And Extinction Of A Reward-Seeking Task, Nikki Sullivan

Honors Theses

Repeated exposure to stress is known to have a myriad of effects on the brain, contributing to the development of psychiatric disorders, such as anxiety, depression, and drug addiction. For example, rats undergoing repeated social stress develop increased cocaine self-administration. These effects of stress are not well-understood and are related to changes in the brain reward system. This study investigated the effects of repeated social stress on reward-seeking behavior via the acquisition and extinction of a discriminative stimulus (DS) task and on anxiety-like behavior in the elevated plus maze (EPM). Male rats underwent intermittent social defeat (4 sessions in 10 …

Influences Of Salvinorin A And Sex Differences On Depressive- And Anxiety-Like Behaviors In A Chronic Mild Stress Paradigm, Sarah Mitchell

Theses

Kappa opioid receptors are colocalized with dopamine receptors and are frequently associated with depression, anxiety, stress, and drug use and abuse. KOR antagonism has widely been considered anti-depressive and anxiolytic in animal models while agonism is pro-depressive and anxiogenic. However, recent findings suggest that SalvA, a natural kappa agonist derived from a plant in the mint family, can reduce depressive- and anxiety-like behavior in rats. The current study investigated the effects of chronic mild stress on behavior, attenuation by SalvA, and sex differences. 52 Long-Evans rats, 26 males and 26 females, were exposed to six weeks of CMS. Animals received …

No Evidence That Portion Size Influences Food Consumption In Male Sprague Dawley Rats, Fabien Naniex, Sophie C. Pinder, Megan Y. Summers, Renee M. Rouleau, Eric Robinson, Kevin P. Myers, James E. Mccutcheon

Faculty Journal Articles

In studies of eating behavior that have been conducted in humans, the tendency to consume more when given larger portions of food, known as the portion size effect (PSE), is one of the most robust and widely replicated findings. Despite this, the mechanisms that underpin it are still unknown. In particular, it is unclear whether the PSE arises from higher-order social and cognitive processes that are unique to humans or, instead, reflects more fundamental processes that drive feeding, such as conditioned food-seeking. Importantly, studies in rodents and other animals have yet to show convincing evidence of a PSE. In this …

Disruption Of Hippocampal Multisynaptic Networks By General Anesthetics., Min-Ching Kuo, L Stan Leung

Physiology and Pharmacology Publications

BACKGROUND: Previous studies showed that synaptic transmission is affected by general anesthetics, but an anesthetic dose response in freely moving animals has not been done. The hippocampus provides a neural network for the evaluation of isoflurane and pentobarbital on multisynaptic transmission that is relevant to memory function.

METHODS: Male Long-Evans rats were implanted with multichannel and single electrodes in the hippocampus. Spontaneous local field potentials and evoked field potentials were recorded in freely behaving rats before (baseline) and after various doses of isoflurane (0.25 to 1.5%) and sodium pentobarbital (10 mg/kg intraperitoneal).

RESULTS: Monosynaptic population excitatory postsynaptic potentials at the …

Examination Of Methamphetamine Reinstatement In Female And Male Rats: A Pre-Clinical Model Of Relapse, Steven T. Pittenger

Department of Psychology: Dissertations, Theses, and Student Research

Methamphetamine (meth) dependence is often characterized by persistent and chronic relapse (i.e., return to drug use). There is growing pre-clinical and human evidence suggesting females are at greater risk to relapse. The set of studies presented in this dissertation extended this limited evidence by identifying sex-dependent neural substrates correlated with meth-triggered reinstatement (Experiment 1) and by examining sex-differences in reinstatement triggered by drugs of abuse that are commonly co-abused with meth (Experiment 2). Female and male rats were trained to self-administer meth, received subsequent extinction sessions, and then tested for reinstatement. In Experiment 1, rats were perfused following reinstatement testing …

An Exploration Of The Wheel-Induced Feeding-Suppression, Stephen Benjamin Peckham

Theses and Dissertations (Comprehensive)

Anorexia nervosa is an enigmatic human condition typified by food-restriction that is often accompanied by extensive exercise. This has been modeled in rats in the wheel-induced feeding-suppression (WIFS) model. In this model, animals are given access to a running-wheel, which induces a volitional drop in food-consumption. Short periods of wheel access have induced a feeding-suppression which is effectively reversed by chlorpromazine administration (Adams et al., 2009). Recent attempts at replicating Adams et al.’s (2009) feeding-suppression have, however, been unsuccessful (Peckham et al., 2013). These attempts raised questions as to whether or not the existing methodology is most effective at suppressing …

Rats Acquire Stronger Preference For Flavors Consumed Towards The End Of A High-Fat Meal, Kevin P. Myers

Faculty Journal Articles

Rats learn to prefer flavors associated with postingestive effects of nutrients. The physiological signals underlying this postingestive reward are unknown. We have previously shown that rats readily learn to prefer a flavor that was consumed early in a multi-flavored meal when glucose is infused intragastrically (IG), suggesting rapid postingestive reward onset. The present experiments investigate the timing of postingestive fat reward, by providing distinctive flavors in the first and second halves of meals accompanied by IG fat infusion. Learning stronger preference for the earlier or later flavor would indicate when the rewarding postingestive effects are sensed. Rats consumed sweetened, calorically-dilute …

Rats Acquire Stronger Preference For Flavors Consumed Towards The End Of A High-Fat Meal, Kevin P. Myers

Faculty Journal Articles

Rats learn to prefer flavors associated with postingestive effects of nutrients. The physiological signals underlying this postingestive reward are unknown. We have previously shown that rats readily learn to prefer a flavor that was consumed early in a multi-flavored meal when glucose is infused intragastrically (IG), suggesting rapid postingestive reward onset. The present experiments investigate the timing of postingestive fat reward, by providing distinctive flavors in the first and second halves of meals accompanied by IG fat infusion. Learning stronger preference for the earlier or later flavor would indicate when the rewarding postingestive effects are sensed. Rats consumed sweetened, calorically-dilute …

Loss Of Dendritic Inhibition In The Hippocampus After Repeated Early-Life Hyperthermic Seizures In Rats., Richard Boyce, L Stan Leung

Physiology and Pharmacology Publications

Seizures are relatively common in children and are a risk factor for subsequent temporal lobe epilepsy. To investigate whether early-life seizures themselves are detrimental to the proper function of the adult brain, we studied whether dendritic excitation and inhibition in the hippocampus of adult rats were altered after hyperthermia-induced seizures in immature rats. In particular, we hypothesized that apical dendritic inhibition in hippocampal CA1 pyramidal cells would be disrupted following hyperthermia-induced seizures in early life. Seizure rats were given three hyperthermia-induced seizures per day for three days from postnatal day (PND) 13 to 15; control rats were handled similarly but …

Septohippocampal Gabaergic Neurons Mediate The Altered Behaviors Induced By N-Methyl-D-Aspartate Receptor Antagonists., Jingyi Ma, Siew Kian Tai, L Stan Leung

Physiology and Pharmacology Publications

We hypothesize that selective lesion of the septohippocampal GABAergic neurons suppresses the altered behaviors induced by an N-methyl-D-aspartate (NMDA) receptor antagonist, ketamine or MK-801. In addition, we hypothesize that septohippocampal GABAergic neurons generate an atropine-resistant theta rhythm that coexists with an atropine-sensitive theta rhythm in the hippocampus. Infusion of orexin-saporin (ore-SAP) into the medial septal area decreased parvalbumin-immunoreactive (GABAergic) neurons by ~80%, without significantly affecting choline-acetyltransferase-immunoreactive (cholinergic) neurons. The theta rhythm during walking, or the immobility-associated theta induced by pilocarpine, was not different between ore-SAP and sham-lesion rats. Walking theta was, however, more disrupted by atropine sulfate in ore-SAP than …

The Inadequacy Of Intracranial Stimulation To The Posterior Hypothalamus To Serve As A Reinforcer For Maze Learning In The Rat, John A. Bull

All Master's Theses

Eighteen, 23 hour food deprived, self-stimulating rats were divided into two groups. One group received 20 ICS pulses as a reward for a correct response in a T-maze while the second group received a food reward. The subjects learned for food over 5 days of 10 massed trials per day, but failed to show learning for ICS either within sessions or over days. There was no difference in learning between rats with high bar press rates and those with low rates in either group.