Tried asparagine once, didn't really help. That was about all I could find on the subject. I think for extreme cases of vasoconstriction like BrDfly poisoning they'd pump you full of sedatives... also headaches indeed tend to be caused by blood vessel dilation, constriction not so much. Blood pressure and general tension and also dehydration can all cause headaches as well. For blood vessel dilation induced headaches, small doses of caffeine are apparently a common cure.
I'll close this as requested. Deletion will not be necessary, also then nobody will see your invitation to contact you about vasoconstriction. There must be loads of discussion on that in PD though, google through it... I'd suggest.
