Less sensitive issue of periodical (6)
I believe the answer is:
number
This clue is a triple definition!
'less sensitive' is the first definition.
(numb means insensitive or unfeeling)
'issue' is the second definition.
(synonyms)
'of' acts as a link.
'periodical' is the third definition.
(I know that number is a type of periodical)
(Other definitions for number that I've seen before include "27, say" , "Count; amount" , "Part of musical" , "1,2,3, for instance" , "less sensitive" .)