Dog salivating, Pavlov starts with bell (8)
I believe the answer is:
springer
'dog' is the definition.
(I've seen this before)
'salivating pavlov starts with bell' is the wordplay.
'starts with' indicates taking the first letters (I've seen 'start with' mean this).
'bell' becomes 'ringer' (I've seen this before).
The first letters of 'salivating pavlov' is 'sp'.
'sp'+'ringer'='SPRINGER'
(Other definitions for springer that I've seen before include "Kind of spaniel" , "A spaniel; stone in arch" , "Game dog" , "Shown [AT CRUFTS]" , "A bounder" .)