L. D'Este et al., Distribution of amylin-immunoreactive neurons in the monkey hypothalamus and their relationships with the histaminergic system, ARCH HIST C, 64(3), 2001, pp. 295-303
Amylin (AMY) is a 37 amino acid peptide of pancreatic origin that has been
localized in peripheral and central nervous structures. Both peripheral and
central injection of the peptide causes various effects, including anorect
ic behavior in rats. Prompted by previous reports showing that the anorecti
c effect of AMY is mediated by histamine release, we immunohistochemically
investigated possible relationships between these two systems at the light
microscopical level. Monkey (Macaca fuscata japonica) hypothalamus specimen
s were submitted to immunohistochemical double staining procedures using AM
Y and histidine decarboxylase (HDC) antisera. AMY-immunoreactive neurons we
re found widely distributed in several nuclei of the monkey hypothalamus in
cluding the supraoptic, paraventricular, perifornical, periventricular, ven
tromedial, arcuate, and tuberomammillary nuclei. We detected AMY-immunoreac
tive nerve fibers throughout the hypothalamus, the median eminence and hypo
thalamus-neurohypophysial tract. Although AMY- and HDC-immunoreactive neuro
nal cell bodies occupied distinct hypothalamic zones, many HDC-immunoreacti
ve cell bodies and dendrites, particularly those in the periventricular, ar
cuate, and rostral tuberomammillary regions, were surrounded by numerous AM
Y-immunoreactive nerve fiber varicosities. These findings demonstrate for t
he first time the presence of a discrete number of AMY- immuno reactive neu
rons in the monkey hypothalamus and add morphological support to the experi
mental data demonstrating that AMY probably exerts its influence on food in
take via the histaminergic system.