Is the dopaminergic system involved in the central effects of nicotine in mice?

Pretreatment with ineffective doses of the D1 antagonist SCH23390 but not the D2 antagonist sulpiride reduced hyperactivity induced by nicotine in mice habituated to the test cage. On the other hand, the D1 and D2 antagonists were ineffective in blocking nicotine-induced hypoactivity in naive mice. Finally, SCH23390 and sulpiride did not block the antinociception induced by nicotine. Our data indicate that the dopamine receptors D1 and D2 are not involved in all the central effects of nicotine in mice, but seems to be a substrate for locomotor activation induced by nicotine under specific experimental conditions.