An increase in in vivo release of LHRH and precocious puberty by posterior hypothalamic lesions in female rhesus monkeys (<i>Macaca mulatta</i>)

Windsor-Engnell, Bret M.; Kasuya, Etsuko; Mizuno, Masaharu; Keen, Kim L.; Terasawa, Ei

doi:10.1152/ajpendo.00493.2006

Cited by 7 publications

(5 citation statements)

References 51 publications

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“…With respect to GABA effects on GnRH release, GABA containing terminals synapse directly with GnRH neurons in the rat (Leranth et al, 1985), whereas synaptic contact between GABAergic neurons and GnRH neurons has not been detected in the rhesus macaque (Thind and Goldsmith, 1995). In the macaque, it is possible that other mechanisms may intercede between GABA and GnRH (Windsor-Engnell et al, 2007). Estrogen regulation of regional GABA concentrations has long been implicated in the feedback action of estrogen on gonadotropin release (Mansky et al, 1982).…”

Section: Discussionmentioning

confidence: 99%

Influence of 17β-estradiol and progesterone on GABAergic gene expression in the arcuate nucleus, amygdala and hippocampus of the rhesus macaque

Noriega¹,

Eghlidi²,

Garyfallou³

et al. 2010

Brain Research

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Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the brain, and the responsiveness of neurons to GABA can be modulated by sex steroids. To better understand how ovarian steroids influence GABAergic system in the primate brain, we evaluated the expression of genes encoding GABA receptor subunits, glutamic acid decarboxylase (GAD) and a GABA transporter in the brains of female rhesus macaques. Ovariectomized adults were subjected to a hormone replacement paradigm involving either 17β-estradiol (E), or E plus progesterone (E+P). Untreated animals served as controls. Using GeneChip® microarray analysis and real-time RT-PCR (qPCR), we examined gene expression differences within and between the amygdala (AMD), hippocampus (HPC) and arcuate nuclei of the medial basal hypothalamus (MBH). The results from PCR corresponded with results from representative GeneChip® probesets, and showed similar effects of sex steroids on GABA receptor subunit gene expression in the AMD and HPC, and a more pronounced expression than in the MBH. Exposure to E+P attenuated GAD1, GAD2 and SLC32A1 gene expression in the AMD and HPC, but not in the MBH. GABA receptor subunit gene expression was generally higher in the AMD and HPC than in the MBH, with the exception of receptor subunits ε and γ2. Taken together, the data demonstrate differential regulation of GABA receptor subunits and GABAergic system components in the MBH compared to the AMD and HPC of rhesus macaques. Elevated ε and reduced δ subunit expression in the MBH supports the hypothesis that the hypothalamic GABAergic system is resistant to the modulatory effects of sex steroids.

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Section: Discussionmentioning

confidence: 99%

Influence of 17β-estradiol and progesterone on GABAergic gene expression in the arcuate nucleus, amygdala and hippocampus of the rhesus macaque

Noriega¹,

Eghlidi²,

Garyfallou³

et al. 2010

Brain Research

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“…Glutamate receptors are present in the median eminence, as shown by immunohistochemistry [ 4 , 15 , 16 ]. Perifusion and push-pull perfusion studies of this region also show that glutamate is released [ 45 , 46 ]. Recent morphological and functional study of GnRH identified that the GnRH “dendron”, which has a mixed phenotype of dendrites and axons, is responsive to glutamate stimulation within and near the median eminence [ 47 ].…”

Section: Discussionmentioning

confidence: 99%

Expression of Vesicular Glutamate Transporter 2 (vGluT2) on Large Dense-Core Vesicles within GnRH Neuroterminals of Aging Female Rats

et al. 2015

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The pulsatile release of GnRH is crucial for normal reproductive physiology across the life cycle, a process that is regulated by hypothalamic neurotransmitters. GnRH terminals co-express the vesicular glutamate transporter 2 (vGluT2) as a marker of a glutamatergic phenotype. The current study sought to elucidate the relationship between glutamate and GnRH nerve terminals in the median eminence—the site of GnRH release into the portal capillary vasculature. We also determined whether this co-expression may change during reproductive senescence, and if steroid hormones, which affect responsiveness of GnRH neurons to glutamate, may alter the co-expression pattern. Female Sprague-Dawley rats were ovariectomized at young adult, middle-aged and old ages (~4, 11, and 22 months, respectively) and treated four weeks later with sequential vehicle + vehicle (VEH + VEH), estradiol + vehicle (E2 + VEH), or estradiol + progesterone (E2+P4). Rats were perfused 24 hours after the second hormone treatment. Confocal microscopy was used to determine colocalization of GnRH and vGluT2 immunofluorescence in the median eminence. Post-embedding immunogold labeling of GnRH and vGluT2, and a serial electron microscopy (EM) technique were used to determine the cellular interaction between GnRH terminals and glutamate signaling. Confocal analysis showed that GnRH and vGluT2 immunofluorescent puncta were extensively colocalized in the median eminence and that their density declined with age but was unaffected by short-term hormone treatment. EM results showed that vGluT2 immunoreactivity was extensively associated with large dense-core vesicles, suggesting a unique glutamatergic signaling pathway in GnRH terminals. Our results provide novel subcellular information about the intimate relationship between GnRH terminals and glutamate in the median eminence.

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“…In fact, very similar to maternal behaviors, lesions of the entire mammillary region and surrounding tissue do not eliminate copulation in male rats, but rather, disinhibit it (Lisk, 1966, 1969). Lastly, female rhesus monkeys with posterior hypothalamic lesions extending into the mammillary bodies show advanced puberty (Terasawa et al, 1984; Windsor-Engnell et al, 2007), the onset of which involves DAergic influence in the mPOA (Wuttke et al, 1980; Docke et al, 1987). Thus, DAergic projections from the PHv and mammillary region to the mPOA may be an important contributor to the balance of inhibitory and excitatory inputs influencing a range of reproductive processes.…”

Section: Discussionmentioning

confidence: 99%

Dopaminergic projections to the medial preoptic area of postpartum rats

Miller

Lonstein

2009

Neuroscience

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Dopamine receptor activity in the rodent medial preoptic area (mPOA) is crucial for the display of maternal behaviors, as well as numerous other physiological and behavioral functions. However, the origin of dopaminergic input to the mPOA has not been identified through neuroanatomical tracing. To accomplish this, the retrograde tracer Fluorogold was iontophoretically applied to the mPOA of postpartum laboratory rats, and dual-label immunocytochemistry for Fluorogold and tyrosine hydroxylase later performed to identify dopaminergic cells of the forebrain and midbrain projecting to the mPOA. Results indicate that the number of dopaminergic cells projecting to the mPOA is moderate (~90 cells to one hemisphere), and that these cells have an unexpectedly wide distribution. Even so, more than half of the dual-labeled cells were found in what has been considered extensions of the A10 dopamine group (particularly the ventrocaudal posterior hypothalamus and adjacent medial supramammillary nucleus), or in the A10 cells of the ventral tegmental area. The rostral hypothalamus and surrounding region also contained numerous dual-labeled cells, with the greatest number found within the mPOA itself (including in the AVPV and PVpo). Notably, dual-labeled cells were rare in the zona incerta (A13), a site previously suggested to provide dopaminergic input to the mPOA. This study is the first to use anatomical tracing to detail the dopaminergic projections to the mPOA in the laboratory rat, and indicates that much of this projection originates more caudally than previously suggested. Keywordscatecholamine; dopamine; female; maternal behavior; postpartumThe medial preoptic area (mPOA) of the basal forebrain is necessary for a wide range of physiological and behavioral functions in mammals, including thermoregulation (Bicego et al., 2007;Kumar et al., 2007), arousal (Kumar et al., 2007;Szymusiak et al., 2007), sodium and fluid balance (Bourque et al., 1994), gonadotropin release (Funibashi et al., 2002;Mahesh and Brann, 2005), feeding (Patterson et al., 2006;Leibowitz et al., 2007), and sexual responses (Xiao et al., 2005;Hull and Dominguez, 2006;Balthazart and Ball, 2007). The mPOA has also long been implicated in the control of maternal motivation and behavior in mammals (Numan, 1974;Numan and Insel, 2003;Lonstein and Morrell, 2006). With its high concentration of ovarian steroid receptors (Pfaff and Keiner, 1973;Parsons et al., 1982), receipt of multisensory inputs (Kevetter and Winans, 1981;Rizvi et al., 1992;Chadha and Hubscher, 2008), and connections with regions mediating motor activity and reward Sinnamon, 1992), the mPOA is well-equipped to organize parental responses toward offspring.* To whom correspondence should be addressed, lonstein@msu.edu, Phone: 517-353-8675, FAX: 517-432-2744. NIH Public Access Indeed, postpartum rats with lesions of the mPOA display impaired retrieval and licking of pups, and poor nest construction (Numan and Insel, 2003). Conversely, hormonal or electrical stimulation of the mPOA acti...

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An increase in in vivo release of LHRH and precocious puberty by posterior hypothalamic lesions in female rhesus monkeys (Macaca mulatta)

Cited by 7 publications

References 51 publications

Influence of 17β-estradiol and progesterone on GABAergic gene expression in the arcuate nucleus, amygdala and hippocampus of the rhesus macaque

Influence of 17β-estradiol and progesterone on GABAergic gene expression in the arcuate nucleus, amygdala and hippocampus of the rhesus macaque

Expression of Vesicular Glutamate Transporter 2 (vGluT2) on Large Dense-Core Vesicles within GnRH Neuroterminals of Aging Female Rats

Dopaminergic projections to the medial preoptic area of postpartum rats

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