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Evidence-Based Complementary and Alternative Medicine
Volume 2012 (2012), Article ID 636091, 7 pages
http://dx.doi.org/10.1155/2012/636091
Research Article

Rhynchophylline Protects Cultured Rat Neurons against Methamphetamine Cytotoxicity

1Faculty of Science, The Chinese University of Hong Kong, Hong Kong
2Jiujianpeng Technology R&D Center, Linyi, China
3Faculty of Science, Katholieke Universiteit, Leuven, Belgium
4School of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, China
5Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong

Received 19 November 2011; Accepted 7 February 2012

Academic Editor: Ilkay Erdogan Orhan

Copyright © 2012 Dan Dan Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Rhynchophylline (Rhy) is an active component isolated from species of the genus Uncaria which has been used for the treatment of ailments to the central nervous system in traditional Chinese medicine. Besides acting as a calcium channel blocker, Rhy was also reported to be able to protect against glutamate-induced neuronal death. We thus hypothesize that Rhy may have neuroprotective activity against methamphetamine (MA). The primary neurons were cultured directly from the cerebral cortex of neonatal rats, acting as in vitro model in the present study. The neurotoxicity of MA and the protective effect of Rhy were evaluated by MTT assay. The effects of MA, Rhy or their combination on intracellular free calcium concentration ([Ca2+]i) were determined in individual neocortical neurons by the Fluo-3/AM tracing method. The MTT assay demonstrated that MA has a dose-dependent neurotoxicity in neuronal cultures. The addition of Rhy prior to the exposure to MA prevented neuronal death. Time course studies with the Fluo-3/AM probe showed that Rhy significantly decreased neuronal [Ca2+]i which was elevated by the exposure to MA. Our results suggested that Rhy can protect the neuronal cultures against MA exposure and promptly attenuate intracellular calcium overload triggered by MA challenge. This is the first report demonstrating an inhibitory effect of Rhy against MA impairment in cultured neurons in vitro.