l-tetrahydropalmatine increases leucine enkephalin levels in corpus striatum of rats.
The effect of chronic l-tetrahydropalmatine (l-THP) administration on the level of leucine enkephalin (Leu-Enk) in rat corpus striatum was studied. After l-THP sc injection once daily for 2 wk, the striatal Leu-Enk level was elevated dose-dependently. However, a single injection of l-THP failed to change the Leu-Enk level. When rats received sc Sch-23390, a selective D1 antagonist, 15 nmol.kg-1 tid for 2 wk, striatal content of Leu-Enk increased from 0.17 +/- SD 0.03 ng.mg-1 tissue in control group to 0.23 +/- SD 0.05 ng.mg-1 tissue in Sch-23390 group (n = 8, P less than 0.05). Sulpiride (Sul), a selective D2 antagonist, 140 mumol.kg-1 sc given bid for 2 wk had no significant effect on the striatal Leu-Enk content. The results suggested that the blockade of D1 receptors by l-THP might be responsible for the increase of the striatal Leu-Enk content in rat.
Zhu
X Z
XZ
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai.
Zhou
Z
Z
Ji
X Q
XQ
Gu
J
J
Luo
L G
LG
Wang
F S
FS
D000470:Alkaloids / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D014150:Antipsychotic Agents; D001552:Benzazepines / Q000494:pharmacology; D001600:Berberine Alkaloids / Q000008:administration & dosage / Q000494:pharmacology*; D003342:Corpus Striatum / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000378:metabolism*; D051381:Rats; D013237:Stereoisomerism; D013469:Sulpiride / Q000494:pharmacology
D000470:Alkaloids; D014150:Antipsychotic Agents; D001552:Benzazepines; D001600:Berberine Alkaloids; C014215:tetrahydropalmatine; D004743:Enkephalin, Leucine; D013469:Sulpiride