Similar properties of fetal and adult amine transporters in the rat brain.
A variety of drug classes, including psychomotor stimulants and antidepressants, interact with monoamine transporters in order to exert their effects. Although these transporters have been extensively characterized in the adult brain, little is known about uptake mechanisms in the fetal system. High affinity dopamine (DA) and serotonin (5-HT) uptake in the striatum and frontal cortex, respectively, were examined in rat fetuses (embryonic day 20; E-20). These results were then compared to uptake in adult rat synaptosomal preparations of the same regions. The data indicate that the fetal (E-20) uptake mechanism is sodium-dependent. Furthermore, the potency of various agents to inhibit transporter function was assessed. These drugs produced a concentration-dependent inhibition of uptake, and the resulting IC50 values were not significantly different from those obtained in the adult preparations. Our results provide evidence that the affinity of monoamine uptake inhibitors for fetal (E-20) DA and 5-HT transporters is similar to that observed with adult transporters. This observation has broad implications when considering neuronal development and in utero exposure to drugs that exert their effects through these transporters.
Hyde
C E
CE
Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157-1083.
Bennett
B A
BA
D000375:Aging / Q000378:metabolism*; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D005333:Fetus / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism
D015306:Biogenic Monoamines; D002352:Carrier Proteins; D012701:Serotonin; D004298:Dopamine