Enhancement of (-)-stepholidine on protein phosphorylation of a dopamine- and cAMP-regulated phosphoprotein in denervated striatum of oxidopamine-lesioned rats.
OBJECTIVE
To study effects of (-)-stepholidine (SPD) on the phosphorylation of a dopamine- and cAMP-regulated phosphoprotein (DARPP-32) in the striatum of oxidopamine-lesioned rats.


METHODS
The amount of dephospho-DARPP-32 was measured by a back-phosphorylation assay.


RESULTS
In the striatum of control rats, SPD per se had no effect on the phosphorylation of DARPP-32, but it antagonized the decrease by 28% of dephospho-DARPP-32 induced by the D1 agonist SK&F-38393. In the denervated striatum of oxidopamine-lesioned rats, SPD decreased the amount of dephospho-DARPP-32 by 44%. The effect of SPD was completely counteracted by the concomitant administration of the D1 antagonist Sch-23390.


CONCLUSIONS
SPD exhibits D1 agonistic action on DARPP-32 phosphorylation in the denervated striatum of oxidopamine-lesioned rats, but it acts as a D1 antagonist in normal striatum.
Guo
X
X
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China.
Liu
J
J
Zou
L L
LL
Jin
J
J
Wang
B C
BC
Jin
G Z
GZ
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000037:antagonists & inhibitors; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D001599:Berberine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003342:Corpus Striatum / Q000378:metabolism*; D018491:Dopamine Agonists; D018492:Dopamine Antagonists / Q000494:pharmacology*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D004791:Enzyme Inhibitors / Q000378:metabolism; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D016627:Oxidopamine; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley
D001552:Benzazepines; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D004791:Enzyme Inhibitors; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D001599:Berberine; C010513:stepholidine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D016627:Oxidopamine