A new neoplastic mast cell grown in culture

Measurement of tele-methylhistamine and histamine in human cerebrospinal fluid, urine, and plasma

A gas chromatographic-mass spectrometric method described by us to measure tele-methylhistamine (t-MH) in brain was used to measure t-MH in human cerebrospinal fluid (CSF), urine and plasma. The presence of t-MH in these body fluids was rigorously established. No pros-methyl-histamine could be detected, and it was used as internal standard to quantify t-MH in the fluids. The mean levels of t-MH were: urine, 943 pmol/mg creatinine; plasma, 12.3 pmol/ml; and CSF, 2.2 pmol/ml. Parallel measurements of histamine by a radioenzymatic method showed, respectively, 182 pmol/mg creatinine; 19.5 pmol/ml; and 388 pmol/ml. The levels of HA in CSF, much higher than those of its metabolite, t-MH, are high enough to stimulate HA receptors in the central nervous system.

Histamine and some of its metabolites in human body fluids

The concentrations of histamine, t-methylhistamine and t-methylimidazoleacetic acid were measured in human cerebrospinal fluid, plasma and urine, Especially noteworthy are the levels of histamine in cerebrospinal fluid which are far higher than those of t-methylhistamine and of t-methylimidazoleacetic acid, and high enough to stimulate histamine receptors in the central nervous system. It is suggested that mast cells, which surround the subarachnoid space, may contribute histamine to the cerebrospinal fluid and may offer a target for drugs and for immunologic actions. The t-methylhistamine and t-methylimidazoleacetic acid levels in cerebrospinal fluid may reflect central histaminergic activity, although a source of these metabolites in addition to histamine needs to be considered.

Ontogeny of subcellular distribution of rat brain tele-methylhistamine

The whole brain content and subcellular distribution of histamine and its metabolite, tele-methylhistamine, were studied during postnatal development of the rat. Brain methylhistamine levels were similar to or greater than histamine levels, indicating that histamine methylation is a major metabolic pathway in neonatal brain, as it is in adults. When calculated per brain, histamine, methylhistamine, and histamine methyltransferase were all maximal 10 days after birth. In neonates, brain histamine was found almost entirely in nuclear fractions, whereas methylhistamine was found almost exclusively in supernatant fractions. By day 20, however, a greater proportion of both amines was localized in subcellular fractions containing synaptosomes, a finding consistent with histamine's suggested transmitter role. The ontogenic pattern of brain methylhistamine questions the mast cell origin of neonatal histamine, but may be consistent with a role for histamine in brain development.