Brain Research 882 2000 95–102 www.elsevier.com locate bres
Research report
Intracerebroventricular injection of senktide-induced Fos expression in vasopressin-containing hypothalamic neurons in the rat
a , b
c b
a a
Yu-Qiang Ding , Juan Shi , Ling-Yun Su , Jun-Qing Xu , Chang-Jun Su , Xiu-E. Guo ,
a
Gong Ju
a
Institute of Neurosciences , Fourth Military Medical University, Xi’an 710032, PR China
b
Department of Anatomy , Fourth Military Medical University, Xi’an 710032, PR China
c
Stomatological College , Fourth Military Medical University, Xi’an 710032, PR China
Accepted 8 August 2000
Abstract
Intracerebroventricular injection of senktide, a selective agonist for neurokinin B receptor NK3, induced Fos expression in many neurons of the rat hypothalamus. Fos-positive neurons were predominantly present in the supraoptic and paraventricular hypothalamic
nuclei, and some of them were seen in the lateral preoptic area, lateral hypothalamic area, arcuate nucleus, perifornical region, posterior hypothalamic area, circular nucleus, and along relatively large blood vessels lateral hypothalamic perivascular nucleus in the anterior
hypothalamus. A double labeling study was performed to examine if vasopressin-containing neurons in the hypothalamus could be activated by the treatment. Neurons with both Fos-like immunoreactivity -LI and vasopressin-LI were found in the paraventricular
nucleus, supraoptic nucleus, circular nucleus and lateral hypothalamic perivascular nucleus. In the supraoptic nucleus, about 87 of vasopressin-containing neurons exhibited Fos-LI, which corresponded to about 64 of Fos-positive neurons in the nucleus. In the
paraventricular nucleus, about 80 of vasopressin-like immunoreactive neurons exhibited Fos-LI, which constituted about 51 of the total population of Fos-positive neurons in the region. The results suggest that NK3 receptor may be involved in the modulation of release
of vasopressin from the hypothalamus in the rat.
2000 Elsevier Science B.V. All rights reserved.
Theme : Endocrine and autonomic regulation
Topic : Osmotic and thermal regulation
Keywords : Neurokinin B receptor; Senktide; Vasopressin; c-fos; Hypothalamus; Rat
1. Introduction NK1, NKA receptor NK2, and NKB receptor NK3
[20,23]. There have been numerous morphological, physio- The mammalian tachykinin family, which includes
logical, and pharmacological studies on functions of SP substance P SP and neurokinin A substance K; NKA
and its receptor, and a significant participation of SP NK1 and neurokinin B neuromedin K; NKB, mediates diverse
receptor in pain mechanisms is now well established biological responses, from a participation in sensory and
[5,17]. However, much less is known about NK2 and NK3 motor functions to a role in the cardiovascular, respiratory,
receptors, especially the latter, as specific antagonists have gastrointestinal, and immune systems and inflammation
been developed for it only recently. [25]. Their actions as neurotransmitters neuromodulators
Previous studies have suggested that NK3 receptor may are mediated by three distinct receptors termed SP receptor
participate in some autonomic functions, such as osmotic regulation, ingestive behavior, and cardiovascular activity
[3,4,7,12,22,25,27,28,31,36]. For example, intracerebro-
Corresponding author. Present address: Department of Cell Biology
ventricular injection of senktide, a selective agonist for
and Anatomy, University of North Carolina at Chapel Hill, CB[ 7090,
NK3 receptor, produced a potent, dose-dependent inhibi-
Chapel Hill, NC 27599, USA. Tel.: 11-919-966-1277; fax: 11-919-966-
tion of salt appetite and an increase in blood pressure and
1856. E-mail address
: yu-qiang dingmed.unc.edu Y.-Q. Ding.
heart rate [21,22]. The increase in blood pressure could be
] 0006-8993 00 – see front matter
2000 Elsevier Science B.V. All rights reserved.
P I I : S 0 0 0 6 - 8 9 9 3 0 0 0 2 8 3 6 - 5
96 Y
inhibited by intravenous injection of vasopressin antago- Cruz Biotechnology, Santa Cruz, CA, USA in PBS
nist, suggesting that senktide-induced pressor response was containing 1 normal donkey serum NDS, 0.3 Triton
mediated by release of vasopressin [12,28]. Moreover, X-100 and 0.03 NaN
overnight at room temperature.
3
immunohistochemical and in situ hybridization studies The sections were then washed in PBS and incubated with
have revealed that NK3 receptor is widely distributed in biotinylated goat anti-rabbit IgG 1:200; Vector Laborator-
the central nervous system of the rat especially in the ies, Burlingame, CA, USA in the NDS incubation medium
hypothalamus [9,15], and that a large proportion of NK3 for 3–4 h, washed again, and reacted with an Elite ABC
receptor-expressing neurons in the paraventricular and Kit 1:200; Vector in PBS for 2–3 h. The sections were
supraoptic nuclei of the hypothalamus contain vasopressin finally reacted with 0.02 diaminobenzidine and 0.003
[10]. However, the role of NK3 receptor in the modulation hydrogen peroxide in 0.05 M Tris–HCl buffer pH 7.6
of release of vasopressin from the hypothalamus is not with nickel intensification.
fully understood. Therefore, in the present study, experi- ments were designed to examine the effects of intracere-
2.3. Double labeling for Fos and vasopressin broventricular administration of senktide on Fos expression
in immunohistologically identified vasopressin-containing Since injection of 0.5 mg of senktide-induced maximal
neurons in the rat hypothalamus. Fos expression in the hypothalamus see Section 3, one
series of sections from the rats with injection of 0.5 mg senktide was subjected to double immunohistochemical
2. Materials and methods staining with anti-Fos and anti-vasopressin antibodies; this
