Referenced in: none

Automatically associated channels: Kir2.3

Title: Inhibition of ion channels by hirsutine in rat pheochromocytoma cells.

Authors: K Nakazawa, T Watano, M Ohara-Imaizumi, K Inoue, K Fujimori, Y Ozaki, M Harada, A Takanaka

Journal, date & volume: Jpn. J. Pharmacol., 1991 Dec , 57, 507-15

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1724991

Abstract
Effects of hirsutine, an alkaloid that produces a potent ganglion blocking effect, were investigated using rat pheochromocytoma PC12 cells. Hirsutine (1 to 10 microM) suppressed dopamine-release evoked by 100 microM nicotine. In voltage-clamped cells, hirsutine (1 to 10 microM) inhibited the inward current activated by 100 microM nicotine. Hirsutine was equipotent to hexamethonium in blocking the nicotine-activated current. The voltage-dependency of the nicotine activated current was not modified by hirsutine. Effects of hirustine on other ion channels were tested to determine its selectivity. Inward currents mediated through ATP-activated channels were scarcely affected by hirsutine (up to 100 microM). However, hirustine (10 microM) inhibited Ba currents passing through Ca channels and K currents activated by depolarizing voltage steps. The results suggest that hirsutine potently blocks nicotinic receptor-channels, but hirsutine also inhibits voltage-gated Ca and K channels. Roles of the inhibition of these channels in the pharmacological effects of hirsutine were discussed.