Catecholamines in a macrophage cell line.

This study provides the first evidence for catecholamine synthesis and release in the RAW264.7 cell line, an important macrophage model. Although catecholamines were low in unstimulated cells, activation with lipopolysaccharide (LPS) induced tyrosine hydroxylase (TH) mRNA and increased extracellular norepinephrine and intracellular dopamine within 48 h.

Catecholamines in murine bone marrow derived mast cells.

Cultured murine bone marrow derived mast cells (BMMC) were found to store high levels of dopamine (3753+/-844 pg/10(7) cells) and occasionally produce norepinephrine and epinephrine. The catecholamine synthesis inhibitor, alpha-methyl-para-tyrosine, decreased intracellular catecholamine concentrations, and activation with ionomycin stimulated dopamine release. Neither dopaminergic receptor antagonists nor exogenous dopamine < or =10 microM affected IL-3-induced cell proliferation.

A study of the potential confounding effects of diet, caffeine, nicotine and lorazepam on the stability of plasma and urinary homovanillic acid levels in patients with schizophrenia.

Ten men inpatients who met DSM-III-R criteria for schizophrenia participated. On five occasions at least one week apart, each subject had an intravenous line placed at 0730 after an overnight fast. On each occasion blood samples were drawn at 0800 and hourly thereafter through 1200 noon for measurement of plasma homovanillic acid (HVA).

Impaired distribution of alpha-methyl-L-p-tyrosine in diabetic rats.

Although alpha-methyl-L-p-tyrosine (alpha-MPT), an inhibitor of catecholamine synthesis, has been used to study catecholamine turnover in diabetic animals, effects of diabetes on metabolism of the drug have not been investigated. In this study, administration of a standard dose of alpha-MPT (250 mg/kg initially and 125 mg/kg at 2 h intervals) resulted in lower plasma and tissue levels of alpha-MPT and its metabolites in streptozocin-diabetic rats than in controls. Two to six hours after the initial dose of alpha-MPT, concentrations of alpha-MPT were 2-8-fold lower in the hypothalamus, medulla/pons, and plasma of diabetic animals than in controls.

Cardiovascular responses and central catecholamines in streptozocin-diabetic rats.

Brain catecholamine levels, spinal cord levels of the norepinephrine metabolite methoxy-hydroxy-phenylglycol (MHPG), and heart rate were measured in nondiabetic and streptozocin-diabetic rats after sham surgery or bilateral carotid ligation. Although carotid ligation increased heart rate in both diabetic and nondiabetic rats, in diabetic animals the response did not differ from the response to sham surgery. Carotid ligation increased epinephrine concentrations in the medulla/pons of diabetic animals but was not associated with alterations in other central catecholamines.