Tetrahydroberberine suppresses dopamine-induced potassium current in acutely dissociated CA1 pyramidal neurons from rat hippocampus

• Published in: Neuroscience letters Vol. 207; no. 3; pp. 155 - 158
• Main Authors: Wu, Jie, Jin, Guo-Zhang
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 05.04.1996; Elsevier
• Subjects: Animals; Berberine - analogs & derivatives; Berberine - pharmacology; Biological and medical sciences; Calcium Channel Blockers - pharmacology; Dissociated neurons; Dopamine; Dopamine - pharmacology; Dose-Response Relationship, Drug; Hippocampus - drug effects; K + current; Medical sciences; Miscellaneous; Neuropharmacology; Patch-clamp; Pharmacology. Drug treatments; Potassium Channels - drug effects; Pyramidal Cells - drug effects; Rat hippocampus; Rats; Rats, Wistar; Tetrahydroberberine; Tetrahydroberberine; K + current; Dissociated neurons; Dopamine; Rat hippocampus; Patch-clamp; Rat; Rodentia; Central nervous system; Ionic current; Central depressant; Catecholamine; Vertebrata; Alkaloid; Mammalia; Animal; Neurotransmitter; Mechanism of action; Pyramidal neuron; Potassium; Hippocampus; Brain (vertebrata)
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/0304-3940(96)12522-2

Effects of tetrahydroberberine (THB) on dopamine (DA)-induced response have been investigated in single pyramidal neurons freshly dissociated from CA1 area of the hippocampus using the nystatin perforated patch-clamp, whole-cell recording technique under voltage-clamp configuration. At a holding potential ( V H) of −20 mV, DA-induced responses included a transient outward current, a slow inward current and a combination of the two. The outward current had a reversal potential of −83.5±8.0 mV which was close to K + equilibrium potential and was sensitive to TEA, suggesting that this outward current was carried by K +. Application of THB reversibly suppressed three type responses induced by DA with different degrees of inhibitory ratio. THB inhibited the DA-induced outward current in a concentration-dependent manner with an IC 50 of 13 μM. The maximal value of the concentration-response curve for DA-induced outward current was suppressed by THB, sugegsting a non-competitive inhibition. The results support the hypothesis that THB acts as a novel dopaminergic system antagonist. Furthermore, THB inhibits the DA-induced K + current non-competitively in single dissociated cells, implying that THB may exhibit other pharmacological action on the central nervous system.