Propentofylline treatment on open field behavior in rats with focal ethidium bromide-induced demyelination in the ventral surface of the brainstem

• Rats were submitted (EB) or not (NBE) to ethidium bromide-induced focal demyelination.
• The long-term effects of propentofylline (PPF) were examined on open field behavior and motor coordination.
• In rats of EB group, PPF restored both the open field behavior and motor coordination.
• In rats of NBE group, PPF decreased both the open field behavior and motor coordination.
• These contradictory data were explained by the PPF-induced decrease in dopaminergic function.

Propentofylline (PPF) is a xanthine derivative with pharmacological effects that are distinct from those of classic methylxanthines. It depresses the activation of microglial cells and astrocytes, which is associated with neuronal damage during neural inflammation and hypoxia. Our previous studies showed that PPF improved remyelination following gliotoxic lesions that were induced by ethidium bromide (EB). In the present study, the long-term effects of PPF on open field behavior in rats with EB-induced focal demyelination were examined. The effects of PPF were first evaluated in naive rats that were not subjected to EB lesions. Behavior in the beam walking test was also evaluated during chronic PPF treatment because impairments in motor coordination can interfere with behavior in the open field. The results showed that PPF treatment in unlesioned rats decreased general activity and caused motor impairment in the beam walking test. Gliotoxic EB injections increased general activity in rats that were treated with PPF compared with rats that received saline solution. Motor incoordination was also attenuated in PPF-treated rats. These results indicate that PPF reversed the effects of EB lesions on behavior in the open field and beam walking test.

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