Biomedical subjects

Matthew P Galloway

Publications and source records attributed to Matthew P Galloway.

3 recordsLinked to original sources

PubMed2003

Extracellular glutamate decrease in accumbens following cued food delivery.

This study examined the effects of cued vs non-cued food delivery/consumption on extracellular glutamate and dopamine in the nucleus accumbens of food-deprived rats. Animals that always received a food pellet following a series of auditory tones showed a significant decrease in extracellular glutamate following food consumption, whereas animals that had not been previously exposed to tone-food pairing did not (p<0.05). In contrast, extracellular dopamine was significantly increased in the nucleus accumbens during the first time period after food consumption (p<0.05) regardless of whether animals had been exposed to prior tone-food pairing. Results suggest that food delivery/consumption is associated with a decrease in accumbal glutamate if food delivery has been previously paired with predictive environmental cues.

Acoustic Stimulation↗

PubMed2002

Regulation of striatal dopamine neurotransmission by nitric oxide: effector pathways and signaling mechanisms.

An important role for the reactive gas nitric oxide (NO) in regulating striatal dopaminergic neurotransmission was identified shortly after initial observations indicated that this unorthodox neurotransmitter mediates many of the influences of glutamatergic neurotransmission in the cerebellum, cortex, and hippocampus. While the precise actions of NO on striatal presynaptic and postsynaptic elements remain to be fully characterized, the recent application of sophisticated anatomical, neurochemical, and electrophysiological approaches to the study of nitrergic signaling has revealed that NO exerts a powerful influence both on tonic extracellular dopamine (DA) levels and phasic DA neuron spike activity via the modulation of intrinsic striatal mechanisms and striatonigral feedback loops. Although the nature of the NO-mediated modulatory influence on DA neurotransmission was initially clouded by seemingly conflicting neurochemical observations, a growing body of literature and understanding of the diverse signaling mechanisms and effector pathways utilized by NO indicates that NO exerts a primary facilitatory influence over tonic and phasic dopaminergic neurotransmission under physiological conditions. A review of neurochemical and electrophysiological studies examining the influence of endogenous and exogenous NO on DA neurotransmission indicates that NO signaling exerts multiple effects on local striatal circuits and projection neurons involved in regulating basal ganglia output and nigrostriatal DA neuron activity. In addition to summarizing these influences, the current review focuses on the mechanisms utilized by striatal NO signaling pathways involved in modulating DA transmission at the level of the terminal and cell body and attempts to integrate these observations into a functional model of NO-dependent regulation of basal ganglia systems.

Animals↗

PubMed2002

Magnetic resonance spectroscopy: neurochemistry and treatment effects in affective disorders.

Recent developments in the clinical capabilities of magnetic resonance spectroscopy (MRS) have provided researchers with considerable insight into potential neurochemical alterations associated with the pathology and treatment of affective disorders. This review focuses on the clinical application of MRS to the study of affective disorders, discusses the major MRS visible neurochemicals, and addresses some essential principles of MRS methodology, such as pulse sequences and neurochemical quantitation. Additionally, some of the more recent key findings in the area of mood disorders and their treatment are highlighted, including pharmacological effects and mechanisms. For example, several independent groups have reported alterations in levels of choline, myoinositol, N-acetylaspartate, and gamma-aminobutyric acid in the central nervous systems of patients with major depression, bipolar disorder, panic disorder, or obsessive-compulsive disorder. Finally, the current direction of advances and areas of further investigation are discussed. This review will afford the reader a fundamental foundation in the applications of MRS in mood disorders and an update on some of the current findings in this rapidly developing discipline.

Animals↗