Concomitant variation in immunoreactivity for enkephalins and neutral endopeptidase in the median eminence of the lactating rat.
In the brain, neutral endopeptidase (NEP) is implicated in the biological inactivation of enkephalins and substance P. NEP, enkephalins and neurokinins were detected by immunocytochemistry in the median eminence (ME) of lactating female rats either freely nursing or separated from their pups for 48 h. A significant decrease in enkephalin and NEP immunoreactivity was observed in the external zone of the ME after pup removal. In both animal groups, neurokinin immunoreactivity was absent from this region. These results indicate that: (1) a concomitant variation in immunoreactivity for enkephalins and NEP occur in the ME of the lactating rat; (2) in the ME during lactation, NEP may essentially be implicated in the biological degradation of enkephalins.
INSERM U156, Lille, France.
F
F
Vandenbulcke
P
P
Ciofi
J C
JC
Beauvillain
D000818:Animals; D004745:Enkephalins / Q000032:analysis / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D007774:Lactation / Q000378:metabolism*; D008473:Median Eminence / Q000166:cytology / Q000378:metabolism*; D015260:Neprilysin / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012934:Social Isolation
D004745:Enkephalins; D015260:Neprilysin