Striatal dopamine release in vitro from immature male rats shows enhanced responsiveness to pulsatile, but not continuous, infusions of L-dopa.
In the present experiment we compared the effects of continuous versus pulsed infusions of L-beta-3,4,dihydroxyphenylalanine (L-DOPA) upon dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) release in vitro from superfused corpus striatal tissue fragments of immature (25-32 day) and adult (90-120 day) male rats. In response to two pulse infusions of L-DOPA (5 microM) a significantly greater amount of dopamine and DOPAC was released from the striatal fragments of immature vs adult males. In contrast, when L-DOPA was infused continuously throughout the superfusion virtually identical amounts of dopamine and DOPAC were obtained for immature and adult male rats. No differences in postsuperfusion dopamine tissue content were obtained between adult and immature rats following the two pulses or continuous infusion of L-DOPA. These results suggest that the corpus striatum of the immature rat has an enhanced capacity to convert and release dopamine in response to a submaximal pulsatile infusion of L-DOPA.
Dluzen
D
D
Department of Anatomy, Northeastern Ohio Universities, College of Medicine Rootstown 44272-9989.
McDermott
J
J
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D007980:Levodopa / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D011673:Pulsatile Flow; D051381:Rats; D011919:Rats, Inbred Strains
D015102:3,4-Dihydroxyphenylacetic Acid; D007980:Levodopa; D004298:Dopamine