Tl. Horvath et al., HETEROGENEITY IN THE NEUROPEPTIDE Y-CONTAINING NEURONS OF THE RAT ARCUATE NUCLEUS - GABAERGIC AND NON-GABAERGIC SUBPOPULATIONS, Brain research, 756(1-2), 1997, pp. 283-286
Neuropeptide Y, produced in the arcuate nucleus of the hypothalamus, p
lays a key role in the central regulation of anterior pituitary and ap
petitive functions. The pleiotropic nature of neuropeptide Y in these
mechanisms indicates the existence of heterogeneity in the hypothalami
c neuronal population producing neuropeptide Y. In this study, we repo
rt the coexistence of neuropeptide Y and the amino acid transmitter, g
amma-aminobutyric acid (GABA), in neuronal perikarya of the arcuate nu
cleus. Fluorescent double immunolabeling for neuropeptide Y and glutam
ic acid decarboxylase was carried out on vibratome sections collected
through the hypothalamic arcuate nuclei of animals that were pretreate
d with colchicine. It was found that about one third of the neuropepti
de Y-producing arcuate nucleus perikarya co-expressed glutamic acid de
carboxylase. This population of neuropeptide Y-containing GABAergic ne
urons were distributed longitudinally within the arcuate nucleus locat
ed predominantly in its dorsomedial aspects. These results show that t
here are at least two distinct populations of neuropeptide Y-producing
neurons in the arcuate nucleus: a subset of neuropeptide Y and GABA-c
o-producing neurons located in the dorsomedial arcuate nucleus and a s
ubset of non-GABAergic neuropeptide Y cells located in the ventral arc
uate nucleus. This heterogeneity in the neuropeptide Y-producing perik
arya of the hypothalamus may help explain adverse neuroendocrine and b
ehavioral effects of arcuate nucleus neuropeptide Y.