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Biomedical subjects

V Glover

Publications and source records attributed to V Glover.

13 recordsLinked to original sources

Abnormal platelet 5-hydroxytryptamine uptake and imipramine binding in postnatal dysphoria.

Platelet 14C-5-hydroxytryptamine (14C-5-HT) uptake, 3H-imipramine binding and monoamine oxidase (MAO) activity were measured in women 5 days postpartum and compared with depression scores (Edinburgh Postnatal Depression Scale) at that time and 6 weeks later. Mean Km of 14C-5-HT uptake was significantly reduced in the group showing dysphoria at 5 days (p less than 0.01). Mean Kd of 3H-imipramine binding was significantly increased in the group who later went on to become depressed at 6 weeks postpartum (p less than 0.03). Vmax for 14C-5-HT uptake, Bmax for 3H-imipramine binding and MAO activity did not differ between depressed and non-depressed patients on either occasion. Although the observed changes manifested in a system known to be disturbed in other forms of depression, they were in affinity rather than Bmax or Vmax. Even though probably not of direct physiological significance, such results, if confirmed, together with other pointers in the literature, suggest biochemical abnormalities specific to the puerperal period.

Adult

A coupled peroxidatic oxidation technique for the histochemical localization of monoamine oxidase A and B and benzylamine oxidase.

A coupled peroxidatic oxidation technique is presented which employs benzylamine and tyramine as substrates and clorgyline, deprenyl, phenelzine and pargyline as specific inhibitors. Using this technique with frozen sections of human term placenta and rat liver, the histochemical localization of monocamine oxidase A and B and bnezylamine oxidase has been demonstrated.

Animals

Monoamine mechanisms in chronic schizophrenia: post-mortem neurochemical findings.

Dopamine and its metabolites homovanillic acid and dihydroxyphenylacetic acid, noradrenaline, serotonin and its metabolite 5-hydroxyindoleacetic acid, and tryptophan and its metabolite kynurenine have been assayed in 9 schizophrenic and 10 control brains, together with the monoamine-related enzymes tyrosine hydroxylase monoamine oxidase, dopamine-beta-hydroxylase, and catechol-o-methyl-transferase. In schizophrenic brains dopamine, noradrenaline and serotonin were significantly increased in some areas of corpus striatum, but there were no significant changes in enzyme activity or monoamine metabolite concentrations in any of the brain areas examined. The findings are not consistent with theories that serotonin or noradrenaline stores are grossly depleted or noradrenaline neurones have degenerated, or that monoamine oxidase activity is abnormal, in schizophrenia, and provide no direct support for the hypothesis that dopamine neurones are overactive.

Aged

Deprenyl administration in man: a selective monoamine oxidase B inhibitor without the 'cheese effect'.

After pretreatment with the selective monoamine oxidase B inhibitor, (-)-deprenyl, in doses sufficient for complete inhibition of the platelet enzyme, 4 normal and 6 parkinsoniam volunteers (2 receiving levodopa and 2 levodopa plus carbidopa) suffered no adverse pressor reaction ('cheese effect') after challenge with oral tyramine in amounts considerably greater than those likely to be encountered in a normal diet. Nor did the levodopa-deprenyl combination itself result in a pressor response. Normal human intestinal mucosa was shown predominantly to contain the deprenyl-insensitive A form of the enzyme, which presumably degraded administered tyramine in the deprenyl-treated volunteers; even those receiving the drug for prolonged periods manifested no 'cheese effect', suggesting that the A form remained uninhibited. Intestinal monoamine oxidase A was able to oxidise dopamine, whereas in human platelet or striatum the amine is a monoamine oxidase B substrate. Like tyramine, oral phenylethylamine challenge with amounts greater than those known to be present in a normal diet similarly gave rise to no adverse reaction in (-)-deprenyl-treated subjects; the reasons for this remain to be determined.

Adult

Absence of "cheese effect" during deprenyl therapy: some recent studies.

Although the selective monoamine oxidase (MAO) B inhibitor, (-)deprenyl, has been shown to be free from the "cheese effect" in man after tyramine challenge, the reason for this is far from clear: it may well be independent of the selective inhibitory action of the drug, for during chronic administration there is some evidence to suggest that both A and B forms of the enzyme are equally inhibited. By-passing the putative MAO A gut barrier in the pig (chosen because it possesses MAO B alone in all other tissues) by intravenous tyramine administration into the deprenyl-pretreated animal failed to provoke a pressor response, despite substantial MAO inhibition. Conversely, clorgyline (MAO A inhibitor) pretreatment, which resulted in minimal MAO inhibition, produced a profound hypertensive response, resembling that observed with the non-MAO-inhibiting drug, isoniazid. The most parsimonious explanation for these findings may be that two separate but closely associated pharmacological effects are normally found with "orthodox" MAO inhibitors, enzyme inhibition proper and facilitation of noradrenaline release from its binding sites during tyramine challenge.

Amphetamines