the invention relates to a family of hexapeptide compounds exhibiting activity with regard to the orl - 1 receptor . the compounds share a general formula of arg - tyr - tyr - arg - trp - arg , and may be constructed having modifications or substitutions at any position , and may include modifications of the amino - and carboxy - termini of the hexapeptide . these compounds include agents exhibiting agonist activity and antagonist activity when exposed to the human orl - 1 receptor . as such , the hexapeptides may be useful as analgesics , anxiolytics , diuretics , and anti - cancer agents .