TY - JOUR AU - DONG Zhao-jun AU - JIN Guo-zhang AU - HUANG Hua-yu PY - 2016 TI - Augmentation of dopamine release by (-)-stepholidine from rabbit and rat caudate slices JF - Acta Pharmacologica Sinica; Vol 16, No 6 (November 1995): Acta Pharmacologica Sinica Y2 - 2016 KW - N2 - AIM: To study the effect of (-)-stepholidine (SPD) on dopamine (DA) release evoked by electric stimulation on slices of rabbit caudate nucleus. METHODS: Slices of rabbit caudate nucleus were preincubated with [3H]DA and then perfused and stimulated electrically. RESULTS: Quinpirole (Qui), a selective DA D2 receptor agonist, reduced [3H]DA overflow elicited by 24 mA electric stimulation (IC50 = 0.12, 95% confidence limits 0.09-0.17 mumol . L-1). SPD markedly increased the potential of the stimulation-evoked [3H]DA overflow in a dose-dependent manner and reversed Qui (1 mumol . L-1)-induced attenuation of [3H]DA release. The pA2 value calculated from the data of [3H]DA overflow for SPD was 7.495. In the experiments with rat caudate nucleus slices, SPD (0.1 mmol . L-1) increased the [3H]DA outflow from 3.3 +/- 0.2% to 6.5 +/- 0.5% of the tissue [3H]DA content, which was further enhanced by the protein kinase C (PKC) activator phorbol 12,13-dibutyrate (PDB, 1 mumol . L-1) to 10.1 +/- 1.0% of the total [3H]DA in the tissue. CONCLUSION: SPD is a presynaptic D2 autoreceptor antagonist and induces a synergic effect on [3H]DA release process with PKC. UR - http://www.chinaphar.com/article/view/7083