Functional activation of punch-cultured magnocellular neuroendocrine cells by glutamate receptor subtypes

Meeker, Rick B.; Currás, Margarita C.; Stewart, Jay M.; Serje, Adriana; Al-Ghoul, Walid M.

doi:10.1016/s0165-0270(99)00042-4

Cited by 14 publications

(16 citation statements)

References 42 publications

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“…These results, as well as those demonstrating that NMDA-R activation triggers VP release in SON magnocellular cells Swenson et al, 1998;Meeker et al, 1999), support the idea that NR2B-containing NMDA-Rs are involved in osmoregulation. NR2B subunits may also be involved in developmental processes within the SON (Currá s and Dao, 1998).…”

Section: Nr2b Expression In the Hypothalamussupporting

confidence: 82%

“…D-aspartate, a putative neurotransmitter candidate that can also activate NMDA-Rs, has also been found in some of these nuclei (Schell et al, 1997). Experiments employing radioligand binding (see, e.g., Meeker et al, 1994), Ca 2ϩ imaging (see, e.g., van den Pol et al, 1990;Dayanithi et al, 1995, Meeker et al, 1999, and electrophysiological recordings (see, e.g., Gribkoff, 1991;Hu and Bourque, 1992;Dudek et al, 1993;Ding et al, 1994;Yang et al, , 1995Yang and Hatton, 1997;Meeker et al, 1999;Spergel et al, 1999) all provide evidence for NMDA-R involvement in hypothalamic function.…”

Section: Nr2b Expression In the Hypothalamusmentioning

confidence: 99%

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N-methyl-D-aspartate receptor subunit NR2B is widely expressed throughout the rat diencephalon: An immunohistochemical study

et al. 2000

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Glutamate (Glu), a major excitatory neurotransmitter within the hypothalamus and thalamus, acts upon many receptors, including the N-methyl-D-aspartate (NMDA) subtype. Abundant evidence suggests that variations in the subunit composition of NMDA receptors (NMDA-Rs) contribute to differences in Glu's immediate electrophysiological effects as well as to the patterns of signal transduction cascades it triggers to mediate long-term changes in neuronal function. We have previously shown that hypothalamic NMDA-Rs containing the NR2B subunit may be involved in the control of eating as well as in the mediation of physiological responses to osmotic stimuli. To broaden our understanding of diencephalic NMDA-R participation in other functions, we localized the NR2B subunit in the diencephalon of the adult male rat using immunoperoxidase, immunogold, and immunofluorescence techniques and an affinity-purified polyclonal antibody specific for the NR2B subunit of the NMDA-R. In addition, we used a monoclonal NR2B antibody with immunoperoxidase detection to confirm the NR2B distribution seen with the polyclonal antibody. In the hypothalamus, the highest levels of NR2B immunoreactivity (-ir) were found in the magnocellular neurosecretory system, including the paraventricular and supraoptic nuclei. A new finding was that intense NR2B-ir was present within perivascular "accessory" magnocellular groups of this system, including the nucleus circularis, anterior fornical nucleus, and scattered clusters of lateral hypothalamic cells apposed to blood vessels. Robust NR2B-ir was also present within the arcuate nucleus, the median eminence, and the tuberal nucleus, and light immunostaining was found in all other hypothalamic nuclei examined. In the thalamus, the highest NR2B-ir was observed in the medial habenula and the anterodorsal, paraventricular, rhomboid, reticular, and dorsal lateral geniculate nuclei. As in the hypothalamus, all thalamic nuclei examined displayed at least light immunostaining for this subunit. Control sections, including those incubated with the polyclonal NR2B antibody preadsorbed with its fusion protein, were virtually devoid of immunostaining. This demonstration that the NR2B subunit of the NMDA-R is widely distributed in the diencephalon, implicates it in a wide variety of functions, and provides a useful anatomical framework for establishing a comprehensive map of Glu receptor populations within this major subdivision of the brain.

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Section: Nr2b Expression In the Hypothalamussupporting

confidence: 82%

Section: Nr2b Expression In the Hypothalamusmentioning

confidence: 99%

N-methyl-D-aspartate receptor subunit NR2B is widely expressed throughout the rat diencephalon: An immunohistochemical study

et al. 2000

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“…The major excitatory transmitter driving the activation of MNCs is thought to be glutamate [10, 11]. Abundant glutamatergic synaptic inputs into the SON [12, 13]provide the opportunity for stimulation of each of the major subtypes of glutamate receptors [14, 15, 16, 17], including the induction of bursting patterns of activity associated with hormone release by NMDA glutamate receptor stimulation [18]. In vitro, the broad-spectrum glutamate receptor antagonist kynurenate blocks osmotically stimulated VP release [19].…”

Section: Introductionmentioning

confidence: 99%

Sustained Increases in Activating Transcription Factor-2 and Activator Protein-2 in the Rat Supraoptic Nucleus during Water Deprivation

Meeker¹,

Fernandes²

2002

Neuroendocrinology

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During increases in plasma osmolality, extrinsic and intrinsic stimuli converge on the neuroendocrine cells within the supraoptic nucleus (SON) and paraventricular nucleus and evoke the release of vasopressin (VP). This release is accompanied by an increase in VP synthesis, but the signal transduction pathways that coordinate these two processes are still poorly understood. Several transcription factors have been suggested to be intermediates in this process, but their expression is often transient in spite of continued VP synthesis. Transcription factor expression during chronic neuroendocrine cell stimulation has rarely been examined. In an effort to identify sustained increases, we examined the expression of several transcription factors in the SON of normal rats and rats deprived of water for 44 h. Alpha and beta isoforms of activator protein-2 (AP-2α; AP-β), activating transcription factor-2 (ATF-2), the phosphorylated form of cyclic AMP response element binding protein and phospho-cJun were all expressed in the rat SON under basal conditions. Increases in AP-2α and ATF-2 were sustained throughout the SON during water deprivation, suggesting that these transcription factors could play a role in the maintenance of VP and oxytocin gene transcription in response to dehydration.

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“…Previous studies have shown that whole cell (42) or intracellular (43) recordings can be obtained from dispersed hypothalamic cultures, or from cultured punches of tissue derived from fetal rat brain (11,33). However, because of the dispersed nature of the cell culture, identification of putative MNCs requires the difficult procedure of postfixation immunohistochemistry (e.g., 43).…”

mentioning

confidence: 99%

Visually guided whole cell patch clamp of mouse supraoptic nucleus neurons in cultured and acute conditions

Stachniak¹,

Bourque²

2006

American Journal of Physiology-Regulatory, Integrative and Comp

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Recent advances in neuronal culturing techniques have supplied a new set of tools for studying neural tissue, providing effective means to study molecular aspects of regulatory elements in the supraoptic nucleus of the hypothalamus (SON). To combine molecular biology techniques with electrophysiological recording, we modified an organotypic culture protocol to permit transfection and whole cell patch-clamp recordings from SON cells. Neonatal mouse brain coronal sections containing the SON were dissected out, placed on a filter insert in culture medium, and incubated for at least 4 days to allow attachment to the insert. The SON was identifiable using gross anatomical landmarks, which remained intact throughout the culturing period. Immunohistochemical staining identified both vasopressinergic and oxytocinergic cells present in the cultures, typically appearing in well-defined clusters. Whole cell recordings from these cultures demonstrated that certain properties of the neonatal mouse SON were comparable to adult mouse magnocellular neurons. SON neurons in both neonatal cultures and acute adult slices showed similar sustained outward rectification above -60 mV and action potential broadening during evoked activity. Membrane potential, input resistance, and rapidly inactivating potassium current density (IA) were reduced in the cultures, whereas whole cell capacitance and spontaneous synaptic excitation were increased, perhaps reflecting developmental changes in cell physiology that warrant further study. The use of the outlined organotypic culturing procedures will allow the study of such electrophysiological properties of mouse SON using whole cell patch-clamp, in addition to various molecular, techniques that require longer incubation times.

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Functional activation of punch-cultured magnocellular neuroendocrine cells by glutamate receptor subtypes

Cited by 14 publications

References 42 publications

N-methyl-D-aspartate receptor subunit NR2B is widely expressed throughout the rat diencephalon: An immunohistochemical study

N-methyl-D-aspartate receptor subunit NR2B is widely expressed throughout the rat diencephalon: An immunohistochemical study

Sustained Increases in Activating Transcription Factor-2 and Activator Protein-2 in the Rat Supraoptic Nucleus during Water Deprivation

Visually guided whole cell patch clamp of mouse supraoptic nucleus neurons in cultured and acute conditions

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