The increase in cyclic-AMP levels elicited by vasoactive intestinal peptide (VIP) in mouse cerebral cortical slices is potentiated by ergot alkaloids.

We have recently observed that noradrenaline potentiates, via the activation of specific ?-receptors, the stimulatory effects of vasoactive intestinal peptide on cyclic-AMP levels. We report here that certain ergot derivatives of the ergopeptine class, such as bromocriptine, ergotamine and codergocrine known to interact with alpha-adrenergic receptors, will also potentiate the effects of VIP on cyclic-AMP levels, without increasing directly the levels of the cyclic nucleotide. To our knowledge, these results demonstrate for the first time the existence of an interaction between a neuropeptide and ergot alkaloids within the cerebral cortex.