THE FORMATION OF NORADRENALINE FROM DIHYDROXYPHENYLSERINE

Differential effect of L-threo-3,4-dihydroxyphenylserine in pure autonomic failure and multiple system atrophy with autonomic failure

“…The basis for the pressor response to L-threo-dops in MSA and the lack of such in PAF may relate to the site of drug action. L-threo-dops can exert a pressor effect by decarboxylation to norepinephrine, outside the CNS either intra or extra-neuronally (Blaschko et al, 1950) which will then directly stimulate adrenergic vascular receptors leading to vasoconstriction. However, despite the marked sensitivity to the vasoconstrictor effect of catecholamines in PAF (Robertson et al,, 1984), the increase in plasma norepinephrine was not sufficient to increase upright blood pressure in our patient.…”

The decarboxylation of amino acids related to tyrosine and their awakening action in reserpine‐treated mice

“…The decarboxylation of 3:4-dihydroxyphenylserine by the mouse-liver enzyme was not tested, but it is known that the acid is slowly decarboxylated by the mammalian decarboxylase (Blaschko et al 1950;Holtz, 1959).…”

“…This enzyme acts not only on 3:4-DOPA, presumably its natural substrate, but also on a number of other amino acids, mostly hydroxylated derivatives of phenylalanine. These observations, summarized elsewhere (Blaschko, 1950;Sourkes, 1955), have shown that the 2:5-and the 2:3-isomers of DOPA are readily decarboxylated by preparations of rat and guinea-pig tissues. L-Tyrosine is not decarboxylated, but its meta-hydroxy analogue (hereafter called metatyrosine) is a substrate of the mammalian enzyme, and it has recently been shown that in normal mice, rats, rabbits and dogs metatyrosine has excitatory actions, which are also thought to be due to the amine formed by the decarboxylation of the amino acid (Mitoma, Posner, Bogdanski & Udenfriend, 1957).…”

“…by reserpine, including g-3:4-dihydroxyphenylserine, since this amino acid is slowly decarboxylated by the mammalian enzyme (Blaschko, Burn & Langemann, 1950 (Blaschko, Holton & Sloane Stanley, 1949); 2:5-dihydroxy-DL-phenylalanine was kindly given to us by Messrs Merck, Sharp and Dohme; 2:3-dihydroxy-DL-phenylalanine was a specimen prepared and previously used by Blaschko & Langemann (1951). The threo-3:4-dihydroxyphenyl-DL-serine, from Farbwerke Hochst, was a gift from Professor H. J. Schumann, Frankfurt a.M.…”

The Actions of Dihydroxyphenylalanine and Dihydroxyphenylserine on the Sleep‐wakefulness Cycle of the Rat After Peripheral Decarboxylase Inhibition

“…It was our aim to study the actions of two catecholamine precursors upon the EEG and the sleep-wakefulness cycle of the rat, of which one, DOPA, was found to produce a marked increase in brain dopamine (Bartholini, Da Prada & Pletscher, 1968), while the other, DOPS, selectively increased noradrenaline (NA) in animal brain (Blaschko, Burn & Langemann, 1950).…”