Life Sciences Commons^™

Possible Breakdown Of Dopamine Receptor Synergism In A Mouse Model Of Huntington's Disease, Samantha F. Kennedy

University of New Orleans Theses and Dissertations

The model of basal ganglia function proposed by Albin, Young and Penney (1989) describes two anatomically independent motor pathways, the direct and indirect. However, under normal conditions striatal dopamine (DA) is required for the expression of motor behavior, and DAergic control of the two pathways (via D1 and D2 receptors, respectively) is dependent on co-activation. We tested for a possible breakdown of D1/D2 synergism using transgenic R6/1 mice bearing the human huntingtin allele (Htt). Motor stereotypy, observed prior to the onset of HD-related symptoms, was rated on a 5-point scale following activation of: A) D1 receptors alone, B) D2 receptors …

The Nucleus Accumbens Core Dopamine D1 And Glutamate Ampa/Nmda Receptors Play A Transient Role In The Performance Of Pavlovian Approach Behavior, Veronica Dobrovitsky

Dissertations, Theses, and Capstone Projects

The role of the nucleus accumbens core (NAc core) continues to be redefined with newly acquired data on neurochemical mechanisms mediating the learning and performance of behavior. Previous empirical data showed that dopamine transmission at the D1 receptor (D1R) plays a transient role in the expression of learned Pavlovian approach behavior. Here we show that, prior to overtraining, dopamine activity at D1Rs specifically within the NAc core is critical for the performance of approach behavior elicited by the recently-acquired reward-paired cue. Blockade of D1Rs in the NAc core, but not the dorsomedial striatum or NAc shell, disrupted approach responses during …

Distribution And Activation Of Catecholaminergic Neurons In The Brain Of Male Plainfin Midshipman Fish: Divergence In Behavior And Reproductive Phenotype, Zachary Ghahramani

Dissertations, Theses, and Capstone Projects

The plainfin midshipman fish, Porichthys notatus, provides an excellent opportunity for delimiting the influence of neurochemical content on vertebrate vocal behavior, in part because the production and recognition of social-acoustic signals is vital to their reproductive behavior. There are two distinct reproductive male morphs that follow divergent developmental trajectories with corresponding alternative reproductive tactics: type I males are the territorial/nesting morph that vocally court females during the summer breeding season while type II males do not court females, but instead sneak spawn in competition with type I males. Catecholaminergic neurons, which synthesize and release the neurotransmitters dopamine or noradrenaline, …

Mechanisms Underlying Executive Function Deficits, Sagar Jayawantrao Desai

Electronic Thesis and Dissertation Repository

In our daily life, we come across situations where we meet unanticipated challenges, we must take certain decisions, pay attention, be flexible and inhibit impulsive actions to achieve goal directed behaviour. During these processes, we unknowingly use sets of interdependent cognitive processes collectively called ‘executive function’. Executive function is mainly regulated by the frontal lobe. Impaired executive function is associated with disorders such as schizophrenia, Alzheimer’s disease, autism and attention deficit hyperactivity disorder (ADHD).

In this thesis, we investigated neurotransmitters and interactions among them regulating executive function. Further, we investigated mechanisms underlying those interactions mediating executive function in rats using …

Prefrontal Cortex Dopamine Transmission Regulates Emotional Memory Processing And Morphine Reward Salience: Implications For Post-Traumatic Stress Disorder And Addiction Comorbidity, Jing Jing Li

Electronic Thesis and Dissertation Repository

Post-Traumatic Stress Disorder (PTSD) and addiction are strongly comorbid. However, the underlying neural mechanisms by which traumatic memory recall may increase addiction liability are poorly understood. The inability to suppress memory recall related to either stressful or rewarding, drug-related experiences may be an underlying neuropsychological feature capable of triggering both PTSD or addiction-related behaviours. Our previous research has shown that transmission through dopamine (DA) D₄ and D₁ receptor subtypes (D₄R, D₁R) within the prefrontal cortex (PFC) strongly modulates emotional memory acquisition and recall (Lauzon et al., 2009). Using olfactory fear conditioning and morphine conditioned …

Examining The Neuronal Dopaminergic Pathway Underlying Sleep Behavior And Related Dopamine Sleep Disorders, Mary Beth Putz

Undergraduate Honors Theses

The human brain is an extremely complex organ with approximately 100 billion different neurons that are constantly sending and receiving messages. These messages are sent using the chemical messengers of the brain: neurotransmitters and neuromodulators. Mechanisms of neural control of sleep are substantially conserved across species. Evidence from multiple animal models including flies, zebrafish, and mice shows that the arousal, or wake phase, is regulated by conserved neuromodulators such as dopamine, norepinephrine, and serotonin. Since these neurotransmitter systems are distributed throughout the brain and sub-serve many functions in addition to sleep, the precise circuit mechanisms by which these neurotransmitters regulate …