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Biomedical subjects

N H Neff

Publications and source records attributed to N H Neff.

At least 199 records · Page 11Linked to original sources
PubMed1972

Fluorometric estimation of 4-hydroxy-3-methoxyphenylethyleneglycol sulphate in brain.

1. A simple, sensitive, and selective method was developed for the fluorimetric estimation of 4-hydroxy-3-methoxyphenylethyleneglycol sulphate (MOPEG-SO(4)) in rat brain.2. MOPEG-SO(4) was isolated on a DEAE Sephadex column. Fluorescence was measured at 465 nm (excitation at 320 nm) after heating the column eluate with acid and reheating after adding ethylene diamine.3. The concentration in brain of MOPEG-SO(4) increased after blockade of its transport from brain by treatment with probenecid and decreased after inhibiting its synthesis by treatment with alpha-methyltyrosine or pargyline.4. Our studies suggest that measurement in changes in the rate of formation of MOPEG-SO(4) may be a useful index of noradrenaline turnover.

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PubMed1971

Monoamine oxidase in sympathetic nerves: a transmitter specific enzyme type.

1. When rat brain or superior cervical ganglion monoamine oxidase was incubated with increasing concentrations of clorgyline, using tyramine as substrate, the inhibition of the enzyme could be represented by a pair of sigmoidal curves joined by a horizontal region where inhibition was constant. Tyramine appeared to be metabolized by two enzymes, one of which was highly sensitive to clorgyline, designated A, whereas the other enzyme, designated B, was less sensitive to clorgyline.2. The ratio of A/B activity for brain was 6/4 while in the ganglion it was 9/1.3. When the experiments were repeated using noradrenaline as the substrate, the inhibition of the enzyme followed a simple sigmoidal curve where deamination was inhibited by low concentrations of clorgyline as observed with enzyme A.4. We conclude that tyramine is deaminated by both A and B enzymes whereas noradrenaline is deaminated only by enzyme A, the enzyme which is most active in the ganglion. Our observations are consistent with the hypothesis that a specific intraneuronal monoamine oxidase plays an important role in the catabolism of noradrenaline in sympathetic nerves.

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