Expression of Fos-Related Antigens, Oxytocin, Dynorphin and Galanin in the Paraventricular and Supraoptic Nuclei of Lactating Rats

Eriksson, Maud; Ceccatelli, Sandra; Uvnäs‐Moberg, Kerstin; Iadarola, Michael J.; Hökfelt, Tomas

doi:10.1159/000126976

Cited by 50 publications

(27 citation statements)

References 57 publications

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“…GAL inhibits action potentials in hypothalamic magnocellular neurosecretory cells (Papas and Bourque, 1997), consistent with evidence that GAL reduces OXY and AVP release (Gundlach and Burazin, 1998) and that expression of GAL in neurosecretory cells changes reciprocally with OXY in lactating rats (Eriksson et al, 1996;Landry et al, 1997). GAL also appears to regulate the secretion of gonadotrophin-releasing hormone (GnRH) and prolactin (Lopez and Negro-Vilar, 1990;Lopez et al, 1993;Horvath et al, 1996;Xu et al, 1996).…”

Section: Discussionsupporting

confidence: 71%

Strain and sex differences in the morphology of the medial preoptic nucleus of mice

et al. 2000

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The medial preoptic nucleus (MPO), which is involved in sexual and maternal behaviors, contains neuronal clusters that have been described as being sexually dimorphic in size and neuropeptide content in a variety of species. A subnucleus in DBA/2J (D2) inbred mice, called the pars compacta of the MPO (MPOpc), is absent in C57BL/6J (B6) inbred mice (Robinson et al. [1985] J. Neurogenet. 2:381-388). We report here on experiments that further characterize strain and sex differences in medial preoptic morphology in D2 and B6 inbred mice. A prominent MPOpc, located within the caudal part of the MPO and dorsal to the suprachiasmatic nucleus, was present in both male and female D2 animals but was absent from B6 animals. MPOpc neurons were darkly stained for Nissl substance and larger than neurons in the surrounding MPO. In D2 brains, galanin-immunoreactive (-ir), oxytocin-ir, vasopressin-ir, and NADPH diaphorase-positive neurons were concentrated within the MPOpc. Fewer similar neurons in the comparable region of the MPO of B6 mice suggests that the absence of the MPOpc is due to absence of these neurons rather than a less compact organization. In D2 animals, the density of galanin-ir neurons in the MPOpc was sexually dimorphic, with higher numbers of galanin-ir neurons in females. Strain differences in galanin-ir, oxytocin-ir, vasopressin-ir, and NADPH diaphorase staining appeared to be limited to the MPOpc. Cholecystokinin-immunoreactive neurons, which have been reported to be numerous in the sexually dimorphic central subdivision of the MPO of rats, were sparse in the MPO of D2 and B6 mice. Confirmation of the MPOpc as an accessory magnocellular neurosecretory nucleus was obtained by finding labeling of MPOpc neurons after injection of DiI into the posterior pituitary.

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Section: Discussionsupporting

confidence: 71%

Strain and sex differences in the morphology of the medial preoptic nucleus of mice

et al. 2000

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“…Or, relaxin transported into the cerebro spinal fluid from the SFO may reach the SON and PVN. Relaxin mRNA has been found in discrete regions of the rat brain, however, such as the anterior olfactory nucleus, taenia tecta, and the hippocampus [10], which supports the idea that relaxin is synthesized within the brain and 44 Neuroendocrinology 1997:66: [38][39][40][41][42][43][44][45][46] Heinc/Di/Ross/Anderson/Jaeobson from there transported to its areas of action in other regions of the brain. Previous studies have shown that estrogen priming is necessary to obtain the optimal action of relaxin in relax ing the pubic symphysis in guinea pigs and mice [1].…”

Section: Rclaxin-induccd Fos In Hypothalamic Nucleimentioning

confidence: 66%

“…It has been previously used to locate OTer gic neurons activated in response to suckling pups [44,45], Other neurons have shown Fos-IR following stimuli such as osmotic stress [24,25], sexual activity [26], and peptide administration [27,28,45]. Our unpublished data indicate that intracerebroventricular injection of re laxin in rats activates c-fos, resulting in the expression of Fos in nuclear regions, including the SON and PVN.…”

Section: Rclaxin-induccd Fos In Hypothalamic Nucleimentioning

confidence: 81%

Relaxin-lnduced Expression of Fos in the Forebrain of the Late Pregnant Rat

Heine

Shi

Ross³

et al. 1997

Neuroendocrinology

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Relaxin, administered parenterally, has been shown to increase the release of oxytocin (OT) into the circulation and increase the firing rate of OTergic neurons. The objective of the present study was to determine if relaxin administration can result in the expression of a transcription factor, suggesting that it alters transcriptional activity within OTergic neurons at the level of the hypothalamus. Primigravid rats were ovariectomized and a jugular cannula was inserted on day 11 of gestation (g11). Pregnancy was maintained by implanting 17β-estradiol and progesterone caplets subcutaneously at the time of ovariectomy. At g19, rats were challenged with intravenous relaxin or isotonic saline and the brains were removed for study. Immunohistochemistry was performed on coronal brain sections, utilizing Fos as a marker of cellular activation. In the group receiving relaxin, Fos-like immunoreactivity (Fos-IR) was abundant only in the supraoptic (SON) and paraventricular nuclei (PVN) of the hypothalamus, as well as in the subfornical organ (SFO). In contrast, Fos-IR in the group given isotonic saline was lacking in these three brain regions. A double label study using antibodies against Fos and OT demonstrated that a majority of the Fos-labeled cells in the hypothalamus were OTergic. Because Fos can act as a transcription factor, we interpret these data to indicate that transcription within OTergic cells is altered following relaxin administration, with abundant Fos-IR being limited to the SON and PVN of the hypothalamus and the SFO during late pregnancy in the rat.

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“…During lactation, levels of pro-dynorphin mRNA were higher in the paraventricular nucleus [55]and terminals of dynorphin neurons make direct contact with TIDA neurons in male rats [56]. Furthermore, Manzanares et al [57]reported increased TIDA neuronal activity after dynor…”

Section: Discussionmentioning

confidence: 99%

Immunoneutralization of Endogenous Opioid Peptides Prevents the Suckling-Induced Prolactin Increase and the Inhibition of Tuberoinfundibular Dopaminergic Neurons

Callahan

Klosterman²,

Prunty³

et al. 2000

Neuroendocrinology

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Previous studies have shown that the endogenous opioid peptides, acting at specific opiate receptor subtypes, are involved in the suckling-induced prolactin secretory response. The prolactin increase elicited by suckling is due, at least in part, to an inhibition of tuberoinfundibular dopaminergic (TIDA) neurons in the hypothalamus. We investigated the effects of immunoneutralization of dynorphin, leu-enkephalin and met-enkephalin on the suckling-induced prolactin increase and on the activity of the TIDA neurons in lactating female rats between days 7 and 12 postpartum. Rats were injected into the right lateral ventricle with antiserum specific for one of these three peptides. Control rats were administered equal amounts of immunoglobulin proteins. Suckling produced a profound and significant increase in prolactin levels, as well as a decrease in DOPA accumulation in the median eminence of lactating rats. Administration of immunoglobulin concentrations of up to 3.6 µg did not inhibit the prolactin secretory response to the suckling stimulus and did not prevent the suckling-induced inhibition of TIDA neurons. Antisera to all three endogenous opioid peptides abolished the suckling-induced prolactin increase and prevented the inhibition in DOPA accumulation in the median eminence. Thus, the endogenous opioid peptides, dynorphin, leu-enkephalin and met-enkephalin, are essential for the prolactin secretory response to suckling and inhibition of TIDA neuronal activity is at least one of the mechanisms of action utilized by these peptides.

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Expression of Fos-Related Antigens, Oxytocin, Dynorphin and Galanin in the Paraventricular and Supraoptic Nuclei of Lactating Rats

Cited by 50 publications

References 57 publications

Strain and sex differences in the morphology of the medial preoptic nucleus of mice

Strain and sex differences in the morphology of the medial preoptic nucleus of mice

Relaxin-lnduced Expression of Fos in the Forebrain of the Late Pregnant Rat

Immunoneutralization of Endogenous Opioid Peptides Prevents the Suckling-Induced Prolactin Increase and the Inhibition of Tuberoinfundibular Dopaminergic Neurons

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