Expression of beta‐adrenergic receptors by astrocytes isolated from adult rat cortex

Salm, A.K.; McCarthy, Ken D.

doi:10.1002/glia.440020507

Cited by 70 publications

(27 citation statements)

References 29 publications

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“…One-way analysis of variance showed no differences among astrocytes from the various brain regions, including reactive astrocytes from the ricin-treated MoV (F,,,,,,, = 1.2, P > 0.05). Salm and McCarthy (1989) demonstrated that astrocytes isolated from adult rat cerebral cortex express p-ARs. We confirmed their observations and also found p-ARs in astrocytes isolated from the striatum, trigeminal motor nucleus (MoV), and cerebellar cortex.…”

Section: Cw-ars On Astrocytesmentioning

confidence: 96%

Expression of adrenergic receptors in individual astrocytes and motor neurons isolated from the adult rat brain

Shao

Sutin

1992

Glia

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Attempts to show the distribution of adrenergic receptors (ARs) in autoradiographs of a brainstem motor nucleus following elimination of motor neurons yielded the unexpected result of an increase in beta-AR density. This increase was related to the gliosis accompanying the motor neuron degeneration. To determine the cells on which the AR subtypes were located, we dissociated cells from various regions of the adult rat brain and subsequently identified astrocytes by glial fibrillary acidic protein (GFAP) immunofluorescence. Slides containing the astrocytes were prepared for autoradiography using the nonselective beta ligand 125I-iodocyanopindolol (125ICYP) or the alpha 1 ligand 125IBE 2254 (125I-HEAT). The addition of the selective beta 1 blocker betaxolol or the beta 2 blocker ICI 118.551 to the incubation medium to displace 125ICYP binding was used to determine the binding of beta-AR subtypes. The great majority (greater than 88%) of isolated astrocytes sampled from the trigeminal motor nucleus, cerebral cortex, striatum, and cerebellum showed beta-AR binding. Astrocytes from the first three regions had similar average densities of beta-ARs, whereas the density in cerebellar astrocytes was 2- to 3-fold greater. The beta 2-AR subtype was proportionally greater than the beta 1 subtype in each region. Reactive astrocytes isolated from the trigeminal motor nucleus after degeneration of motor neurons showed a beta-AR density nearly 2-fold greater than resting astrocytes from the same region, with the beta 1 subtype showing the greater proportional increase. There was no beta-AR binding on trigeminal motor neurons. Astrocytes also showed a significant level of alpha 1-AR binding. No differences in alpha 1-AR binding were found in normal astrocytes isolated from the different regions, nor was there an increase in reactive astrocytes. In contrast, trigeminal motor neurons had an alpha 1-AR density nearly 10 times greater than astrocytes. In terms of the NE modulation of synaptic responses in motor neurons, the distribution of ARs would permit NE to act indirectly through alpha 1 and beta receptors on astrocytes and directly through alpha 1 receptors on motor neurons.

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Section: Cw-ars On Astrocytesmentioning

confidence: 96%

Expression of adrenergic receptors in individual astrocytes and motor neurons isolated from the adult rat brain

Shao

Sutin

1992

Glia

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“…Glial cells may also be targets for noradrenergic innervation within the PVH as both alpha-and beta-adrenergic receptors have been localized in vitro to astrocytes in cultures derived from rat cortical and pituitary tissue (Bicknell et al, 1989;Lerea and McCarthy, 1989;Salm and McCarthy, 1989;Hatton et al, 1991). Another possible target for noradrenergic innervation are blood vessels within the PVH, which have been shown to receive monoaminergic innervation (Swanson et al, 1977).…”

Section: Dph-immunoreactive Innervation Of Vasopressin-and Oxytocin-imentioning

confidence: 99%

Noradrenergic innervation of vasopressin‐and oxytocin‐containing neurons in the hypothalamic paraventricular nucleus of the macaque monkey: Quantitative analysis using double‐label immunohistochemistry and confocal laser microscopy

Ginsberg

Hof

Young

et al. 1994

J of Comparative Neurology

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Previous reports on the rat and monkey hypothalamus have revealed a dense noradrenergic innervation within the hypothalamic paraventricular nucleus as assessed by dopamine-beta-hydroxylase immunohistochemistry. These single-label analyses were unable to delineate the cellular structures which receive this catecholaminergic innervation. Double-label preparations in the rat hypothalamic paraventricular nucleus have demonstrated synaptic interactions between noradrenergic varicosities and magnocellular neurons. However, the density and distribution of varicosities contacting chemically identified magnocellular neurons have not been assessed at the light or electron microscopic level. In this report, single-label immunohistochemistry was used to assess the morphology and distribution of vasopressin- and oxytocin-immunoreactive neurons within the macaque hypothalamic paraventricular nucleus. In addition, double-label immunohistochemistry was combined with confocal laser scanning microscopy to quantify the number of dopamine-beta-hydroxylase-immunoreactive varicosities in apposition to magnocellular neurons expressing vasopressin or oxytocin immunoreactivity. The morphology of chemically identified neurons was also compared to magnocellular neurons in the monkey hypothalamic paraventricular nucleus which were filled with Lucifer Yellow in order to assess the somatodendritic labeling of the immunohistochemical preparation. Qualitative assessment of immunohistochemically identified magnocellular cells indicated that vasopressin- and oxytocin-containing neurons are observed throughout the rostrocaudal extent of the monkey hypothalamic paraventricular nucleus, demarcating this structure from the surrounding anterior hypothalamus. The distribution of the two nonapeptides is complementary, with vasopressin-immunoreactive neurons having a greater somal volume and located in a more medial aspect of the mid and caudal hypothalamic paraventricular nucleus relative to oxytocin-immunoreactive perikarya. For the double-label preparations, a series of confocal optical sections was assessed through the total somal volume of vasopressin- and oxytocin-immunoreactive neurons along with the corresponding dopamine-beta-hydroxylase-immunoreactive varicosities in the same volume of tissue, generating a varicosity-to-neuron ratio which was further characterized morphologically to assess afferent input to the soma and proximal dendrites. Quantitative analysis revealed that vasopressin-immunoreactive neurons received approximately two thirds of their dopamine-beta-hydroxylase-immunoreactive varicosities in apposition to the proximal dendrites and one third in apposition to the somata. Furthermore, vasopressin-immunoreactive neurons received a greater innervation density than oxytocin-immunoreactive neurons, which did not have a differential distribution of varicosities on the proximal dendrites and somata. The distribution of dopamine-beta-hydroxylase-immunoreactive afferents on magnocellular neurons in the hypothalamic paraventricular nucleus...

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“…Hatton et al (1984) demonstrated that norepinephrine (NE) can alter astrocytic morphology in the hypothalamus and pituitary gland. Salm and McCarthy (1989) and Sutin (1991,1992) reported that most astrocytes isolated from various regions of adult rat brain exhibit p-adrenergic receptor binding sites and that the number of p receptor binding sites increase during astroglial hypertrophy. Likewise, glutamate uptake mechanisms were found predominantly in astrocytes in the brain (Martinez-Hernandez et al, 1977;Hertz, 1979;Danbolt et al, 1992).…”

Section: Mechanism Of the Glutamate Inhibition Of Glial Stellationmentioning

confidence: 99%

Glutamate blocks astroglial stellation: Effect of glutamate uptake and volume changes

Shao

Enkvist

McCarthy

1994

Glia

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Neurotransmitters which increase intracellular cAMP levels can cause cultured astroglia to change from a flat, polygonal shape to a stellate morphology. Little is known about how glial stellation can be regulated by other transmitters. In the present study, we demonstrated that L-glutamate blocked isoproterenol (ISO) or dibutyryl-cAMP induced stellation in astroglia. The glutamate inhibition was concentration dependent, with its maximal effect on > 90% of cells at 500 microM. Glutamate also reversed glial stellation within a short period (< 30 min). Glutamate uptake analogues, D-glutamate and D-aspartate, rather than receptor agonists, kainate and quisqualate, mimicked the glutamate effect. Likewise, the glutamate uptake blocker, D-thero-beta-hydroxyaspartate, blocked the glutamate effect. The glutamate inhibition was not a result of inhibition of cAMP formation, since norepinephrine, which inhibited 80% of ISO-stimulated cAMP, also caused glial stellation. Increases in extracellular K+ to 50 mM also reduced glial stellation, whereas 25 mM K+ had little effect. Since 25 mM K+ caused much greater depolarization than 400 microM glutamate, it was unlikely that the effects of both glutamate and high [K+] on glial stellation were due to membrane depolarization. Hypotonic treatment (120 mOsm) enhanced, whereas hypertonic treatment (520 mOsm) prevented, the glutamate reversal of glial stellation. Thus, glial swelling appeared to be a primary mechanism for the inhibitory effect of glutamate and high [K+] on glial stellation. This mechanism could also explain the observation that glutamate inhibited stellation induced by PMA, a PKC activator. Our data suggest that glutamate released from neurons during neuronal activity or pathology can be taken up by astrocytes and alter their morphology. Changes in glial morphology may in turn affect the volume and composition of the extracellular space and, as a result, neuronal activity.

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Expression of beta‐adrenergic receptors by astrocytes isolated from adult rat cortex

Cited by 70 publications

References 29 publications

Expression of adrenergic receptors in individual astrocytes and motor neurons isolated from the adult rat brain

Expression of adrenergic receptors in individual astrocytes and motor neurons isolated from the adult rat brain

Noradrenergic innervation of vasopressin‐and oxytocin‐containing neurons in the hypothalamic paraventricular nucleus of the macaque monkey: Quantitative analysis using double‐label immunohistochemistry and confocal laser microscopy

Glutamate blocks astroglial stellation: Effect of glutamate uptake and volume changes

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