The role of neurotransmitters and neuromodulators in the pathogenesis of cluster headache: a review.

The pathogenesis underlying cluster headache remains an unresolved issue. Although both the autonomic system and the hypothalamus play a central role, the modality of their involvement remains largely unknown. It is, also, unknown why the duration of the pain attacks is so brief and why their onset and termination are abrupt and extremely painful. This review summarizes the evidence to date accumulated in favor of a possible role of anomalies in the metabolism of tyrosine, tryptophan, and arginine in these unresolved issues.