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Regional modulation of the level of cortical neurotrans-mitters in the brain would serve as a new functional brain mapping technique to interrogate the neurochemical actions of the brain. We investigated the utility of the application of low-intensity, pulsed soni-cation of focused ultrasound (FUS) to the brain to modulate the extracellular level of(More)
The ventilatory response to acute hypoxia in mammalian species is biphasic, an initial hyperventilatory response is followed by a reduction in ventilation within 2-3 min below the peak level (roll-off). Brain amino acid neurotransmitters also change during hypoxia. This study explores the role of neurotransmitters in anesthetized adult Sprague Dawley rats(More)
Tyrosine (TYR) is the precursor of the catecholamine (CA) neurotransmitters, dopamine (DA) and norepinephrine (NE). Catecholamines, especially NE, participate in the response of the brain to acute stress. When animals are acutely stressed, NE neurons become more active and tyrosine availability may be rate-limiting. Tyrosine administration, before exposure(More)
Manganese (Mn) and lead (Pb) exposures during developmental period can impair development by direct neurotoxicity or through interaction with iron metabolism. Therefore, we examined the effects of maternal ingestion of Mn or Pb in drinking water during gestation and lactation on iron metabolism as well as behavior in their offspring. Pregnant dams were(More)
Phentermine was shown in the 1970s to inhibit the metabolism of serotonin by monoamine oxidase (MAO), but never was labeled as an MAO inhibitor; hence, it was widely used in combination with fenfluramine, and continues to be used, in violation of their labels, with other serotonin uptake blockers. We examined the effects of phentermine and several other(More)
The effects of dietary protein content on diurnal variations in plasma concentrations of neutral and basic amino acids, and on red blood cell levels of acidic amino acids, were studied in seven normal humans. The subjects consumed, on three consecutive 3-day periods, diets containing 0, 75, or 150 g of egg protein per day; blood was collected at 4-h(More)
Administration of tyrosine, the amino acid precursor of catecholamines, increased blood pressure 38 to 49 percent in rats made acutely hypotensive by hemorrhage; other large neutral amino acids were ineffective. Tyrosine's effect was abolished by adrenalectomy, suggesting that, in hypotensive animals, it acts by accelerating the peripheral synthesis and(More)
Nitric oxide synthase (NOS), necessary for the production of nitric oxide from l-arginine, exists in three isoforms: neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). We have previously demonstrated that blockade of nNOS within the rostral (RVLM) and caudal ventrolateral medulla (CVLM) differentially modulated cardiovascular responses(More)
The enzyme nitric oxide synthase (NOS) which is necessary for the production of nitric oxide from L-arginine exists in three isoforms: neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). Our previous studies have demonstrated the roles of nNOS and eNOS within the rostral (RVLM) and caudal ventrolateral medulla (CVLM) in modulating(More)
We have demonstrated the usefulness of a novel hemoglobin-trapping technique to quantify nitric oxide (NO) concentrations in vivo. Concentric microdialysis probes were implanted into the hippocampus of rats under urethane anesthesia and perfused with 1 microM oxyhemoglobin in artificial CSF to sequester NO in extracellular fluid. The concentration of(More)