Effects of L-threo- and erythro-3,4-dihydroxyphenylserine on learning performance and concentrations of brain noradrenaline and its metabolites in rats.
Effects of L-threo and L-erythro-3,4-dihydroxyphenylserine [DOPS, precursor amino acids for noradrenaline (NA)] on the learning performance in a maze paradigm designed to model on the water maze paradigm using a multicomputerized behavioral analysis system were studied. A marked facilitation of learning performance was observed in rats after an intraventricular injection of 5 micrograms L-threo-DOPS (the s-NA precursor), and this effect was inhibited by a simultaneous administration of 1 or 2 micrograms propranolol (a beta-adrenergic antagonist). As concentrations of brain NA, 3-methoxy-4-hydroxyphenylglycol, and normethanephrine were increased by the injection of 5 micrograms L-threo-DOPS, the effect seemed to be derived from activation of beta-adrenoceptors in the CNS by the formed s-NA. On the other hand, an intraventricular injection of 5 micrograms L-erythro-DOPS (the r-NA precursor) attenuated the learning performance, and this effect was probably caused by the formed r-NA from L-erythro-DOPS.
Harada
H
H
Department of Neuropsychiatry, Kyoto Prefectural University of Medicine, Japan.
Noto
T
T
Tsuji
M
M
Taga
C
C
Hashimoto
H
H
Nakajima
T
T
D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism; D001923:Brain Chemistry / Q000187:drug effects*; D015103:Droxidopa / Q000494:pharmacology*; D007276:Injections, Intraventricular; D007858:Learning / Q000187:drug effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism
D015306:Biogenic Monoamines; D011433:Propranolol; D015103:Droxidopa; D009638:Norepinephrine