Yoshihisa Kitamura, Jun-ichi Kakimura and Takashi Taniguchi
Department of Neurobiology, Kyoto Pharmaceutical University, Misasagi,
Yamashina-ku, Kyoto 607-8412, Japan
Abstract: The planarian, a flatworm, has a high potential for
regeneration, and dopamine plays a key role in its behavior. Planarians
treated with MPTP underwent autolysis and individual death in a concentration-dependent
manner. When the planarian body was cut into anterior, middle and posterior
pieces, each piece subsequently regenerated and reorganized to form a new
individual within approximately 10 days. The anterior piece was significantly
more sensitive than the middle and posterior pieces to MPTP cytotoxicity.
Concomitant treatment with talipexole, an anti-parkinsonian drug, inhibited
MPTP-induced autolysis and individual death in a concentration-dependent
manner. Pramipexole showed a similar protective effect. In addition, post-treatment
with talipexole at 1 hr after MPTP completely inhibited MPTP-induced individual
death. Although MPTP treatment caused 30% of the planarians to undergo autolysis
and individual death within 12 hr, post-treatment with talipexole even at
12 hr completely rescued the remaining 70% of the planarians from death.
These results suggest that the MPTP-treated planarian may be useful as a
novel parkinsonian model in which talipexole has a protective effect even
in the case of post-treatment.
Keywords: Talipexole, Pramipexole, MPTP, Planarian, Parkinsonian worm
model