striatal met- and leu-enkephalin contents were determined after 1 , 3 , 6 , 9 and 12 months of treatment , and one week after the drug withdrawal following a 12-month treatment , enkephalin levels were significantly increased with slight fluctuations in some months and returned to normal one week after the last neuroleptic dose following a 12-month administration .
C0014294
leu-enkephalin
C0014298
enkephalin