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.
D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000201:enzymology; D002611:Cheese / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000139:chemically induced*; D007413:Intestinal Mucosa / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D008996:Monoamine Oxidase Inhibitors / Q000009:adverse effects*; D010300:Parkinson Disease / Q000201:enzymology; D010627:Phenethylamines / Q000009:adverse effects* / Q000652:urine; D013997:Time Factors; D014439:Tyramine / Q000494:pharmacology
D008996:Monoamine Oxidase Inhibitors; D010627:Phenethylamines; D014439:Tyramine