Specific binding of 3H-nicergoline in rat brain: comparison with the selective alpha 1-antagonist 3H-prazosin.

In rat cerebral cortex, the 3H-Nicergoline (an ergot alkaloid derivative) binding was rapid, reversible, saturable and of high affinity. In various structures of the central nervous system except midbrain and cerebellum, the maximum binding capacity (B max) for 3H-Nicergoline is greater that for 3H-Prazosin. The specificity studies of 3H-Nicergoline binding show interactions with alpha 1-adrenergic and serotoninergic receptors. These results are confirmed after irreversible blockade with phenoxybenzamine. In conclusion, as nicergoline is known to cross the blood-brain barrier, this study shows that it exerts its central action on alpha 1-adrenoceptors as well as serotoninergic receptors.