Activation by stress of the habenulo-interpeduncular substance P neurons in the rat.

Substance P levels were significantly decreased in the ventro-tegmental area and the interpeduncular nucleus of rats submitted for 20 min to electric foot-shocks. Substance P levels in the substantia nigra and in the prefrontal cortex were not affected. These results are discussed in light of the selective activation of the mesocortico-prefrontal dopaminergic neurons induced by this stress situation.