PLASTICITY IN EXPRESSION OF IMMUNOREACTIVITY FOR NEUROPEPTIDE-Y, ENKEPHALINS AND NEUROTENSIN IN THE HYPOTHALAMIC TUBEROINFUNDIBULAR DOPAMINERGIC SYSTEM DURING LACTATION IN MICE
P. Ciofi et al., PLASTICITY IN EXPRESSION OF IMMUNOREACTIVITY FOR NEUROPEPTIDE-Y, ENKEPHALINS AND NEUROTENSIN IN THE HYPOTHALAMIC TUBEROINFUNDIBULAR DOPAMINERGIC SYSTEM DURING LACTATION IN MICE, Journal of neuroendocrinology, 5(6), 1993, pp. 599-602
In lactating nursing vs lactating pup-deprived mice, single or multipl
e immunolabeling was performed to compare immunoreactivities (ir) for
neuropeptide Y (NPY), enkephalins (ENK) and neurotensin (NT) in the ty
rosine hydroxylase (TH)-ir hypothalamic tubero-infundibular dopaminerg
ic (TIDA) system. NPY-, ENK- and NT-irs were intensely expressed and c
o-existed in virtually all TH-ir endings in the median eminence (ME) o
f nursing mice. Removal of the pups induced a marked depletion of the
peptide-irs from the ME TH-ir endings. In the arcuate nucleus (ARC) of
colchicine-treated nursing mice which received peripheral injections
of Fluoro-Gold (FG) to retrogradely label neuroendocrine cells, virtua
lly all dorsal A12 TH-ir perikarya simultaneously expressed, with indi
vidual variations, NPY-, ENK- and NT-irs, and all contained FG. These
results suggest that the synthesis of NPY, ENK and NT is enhanced in T
IDA neurons during lactation and that these neuromessengers may be co-
released together with DA from the ME to regulate the suckling-induced
prolactin secretion at the hypothalamic and/or pituitary levels.