The responsiveness of individual hypothalamic neurons to microelectrophoretically administered endogenous amines

Bloom, Floyd E.; Oliver, A; Salmoiraghi, G. C.

doi:10.1016/0028-3908(63)90019-4

Cited by 89 publications

(19 citation statements)

References 25 publications

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“…This percentage compares favorably with the percentage of hypothalamic neurons in situ whose activity is altered by the iontophoretic application of norepinephrine (11). Moreover, Geller (12) (4,12).…”

Section: Resultsmentioning

confidence: 62%

Localization of beta-adrenergic receptors on differentiated cells of the central nervous system in culture.

Ventimiglia¹,

Greene²,

Geller³

1987

Proc. Natl. Acad. Sci. U.S.A.

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Hypothalamic neurons and cortical protoplasmic (type 1) astrocytes in dissociated cultures of rat brain express binding sites for antibodies specific for epitopes related to the fi-adrenergic receptor. Undifferentiated glial progenitor cells of the rat optic nerve do not detectably bind these antibodies, but both of the progeny [oligodendroglia and process-bearing (type 2) astrocytes] express immunologically identified fi-adrenergic receptors. Levels of receptor expression are variable: not all cells of each type express receptors nor is expression uniform on a given cell. The data suggest that cells of the central nervous system express .8-adrenergic receptors but that levels of expression may be determined by the differentiated state of the cells.The actions of catecholamines relate to occupancy of one of two types of receptors, a and ,B, that are distributed on the surfaces of cells in the central nervous system (CNS). Biochemical and autoradiographic techniques have localized these receptor types to various regions ofthe CNS. Recently, autoradiographic techniques have been used to detect expression of f8-adrenergic receptors by measuring binding of radioactive ligands to cells in culture; these studies showed that astrocytes show significant levels of /3-adrenergic ligand binding but binding was not discernible on neurons and oligodendrocytes (1). Additionally, these studies suggested the level of receptor expression by astrocytes is highly variable, with a general trend toward an increase in receptor expression with time in culture (2). Thus, one might hypothesize that the selective expression of l3-adrenergic receptors, in common with that of other gene products, may be influenced by diverse and undefined environmental factors.To investigate the developmental expression of adrenergic receptors, we have employed a reliable, simple method for demonstrating the presence of receptors on single cells in dissociated cultures of mammalian CNS. We now report that antibodies directed against epitopes related to the 83-adrenergic receptor can be used to identify neural cells that express these receptors in culture. Used in combination with other cell-type-specific antibodies, we found that each of the differentiated cell types of the CNS (neurons, astrocytes, oligodendrocytes) displays ,3-adrenergic receptors on the surface of a portion of the cells of that type. Moreover, we have determined that the expression of 8-adrenergic receptors by two glial cells, the process-bearing (type 2) astrocyte and the oligodendrocyte, appears as these cells undergo differentiation. The progenitor cell that gives rise to these cell types does not express ,3-adrenergic receptors. We conclude that the expression of 8-adrenergic receptors may characterize certain sets of differentiated cells of the central nervous system. MATERIALS AND METHODSTissue Culture of Embryonic Hypothalamus. Hypothalami were dissected from the brains of rat embryos at day 17 of gestation. The tissue was minced and incubated in Eagle's basal medium/0.02...

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Section: Resultsmentioning

confidence: 62%

Localization of beta-adrenergic receptors on differentiated cells of the central nervous system in culture.

Ventimiglia¹,

Greene²,

Geller³

1987

Proc. Natl. Acad. Sci. U.S.A.

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“…It is possible that these relatively weak actions were produced by a mechanism which differed from that of NA on the more sensitive cells. These small effects on some spinal neurones could be analogous to those seen with relatively large amounts of NA elsewhere in the central nervous system (see Krnjevic & Phillis, 1963;Bloom, Oliver & Salmoiraghi, 1963;Krnjevid, 1964;Bradley & Wolstencroft, 1965).…”

Section: Discussionmentioning

confidence: 84%

The inhibitory action of noradrenaline and other monoamines on spinal neurones

Engberg¹,

Ryall²

1966

The Journal of Physiology

258

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SUMMARY1. L-Noradrenaline (NA), 5-hydroxytryptamine (5-HT) and acetylcholine (ACh) were administered micro-electrophoretically to feline lumbar neurones while recording their spike potentials extracellularly.2. There was no evidence to suggest that NA acts as an excitatory transmitter in the spinal cord.3. NA had potent inhibitory effects on some interneurones as revealed by a depression of spontaneous and synaptic firing and on the firing to a local application of an excitant amino acid. The effects on Renshaw cells and motoneurones were less marked.4. The depressant actions of 5-HT were less marked than those of NA. ACh and carbamylcholine had depressant effects on some NA-sensitive interneurones but were invariably far less potent and on other NA-sensitive cells were completely inactive.5. NA had no detectable effect on the normal spike amplitude but when the action potentials were reduced by excessive depolarization then both NA and synaptic inhibition increased the spike amplitude; this effect could be due to a hyperpolarization of the cell membrane.6. There was a correlation between the distribution of NA-sensitive cells and the relative densities of NA-containing terminals in various layers of the grey matter.7. It was postulated that NA acts as an inhibitory transmitter released from the terminals of descending pathways in the spinal cord. Other possible mechanisms were discussed but lacked experimental support.

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“…40 % of brain stem neurones were excited and 49 % were depressed by 5-HT (Bradley & Wolstencroft, 1965); while in anaesthetized brain, the characteristic effect of 5-HT has previously been described as depression, e.g. hippocampal cortex (Biscoe & Straughan, 1966) and hypothalamus (Bloom, Oliver & Salmoiraghi, 1963). Thus it is ofthe utmost importance that the effect of anaesthetics be taken into consideration when deciding whether a substance affects neurones at all, and in deciding what its characteristic effect is.…”

Section: Discussionmentioning

confidence: 99%

Excitation and depression of cortical neurones by 5‐hydroxytryptamine

Roberts¹,

Straughan²

1967

The Journal of Physiology

256

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SUMMARY1. 5-Hydroxytryptamine (5-HT) and various 5-HT antagonists have been applied micro-electrophoretically from multibarrelled micropipettes into the environment of single neurones in the post-sigmoid and suprasylvian gyri of the cat cerebral cortex.2. In unanaesthetized animals (encephale isole) a high proportion of neurones (30 %) were excited by 5-HT. This excitation usually had a rapid onset and was seen both in spontaneously active neurones and in otherwise quiescent neurones in which firing was induced by L-glutamate. Some neurones were so sensitive that the uncontrolled diffusion from micropipettes was sufficient to excite them. More cells were excited by 5-HT applied as a cation from solutions of the bimaleate salt than when solutions of the creatinine sulphate salt were used.3. In a high proportion of cells (33 %) spontaneous firing or amino acid excitation was depressed by 5-HT. 4. A mixed effect was seen in a small proportion (6 %) of the cells tested; usually 5-HT caused an excitation initially which was followed by a depression. In other cells, desensitization occurred, and the excitatory effect of 5-HT was diminished or lost. In two cells, however, the depression was reversibly prevented by these antagonists.8. Some cells tested with 5-HT were also tested with ACh or (-noradrenaline. The response of a cell to ACh was not significantly related to its response to 5-HT. The degree of correlation between the responses to noradrenaline and 5-HT was large, but not statistically significant with the small number of cells studied. 9. The effects of 5-HT on cells in animals anaesthetized with oc-chloralose did not differ significantly from its effects in unanaesthetized preparations. It is suggested that the use of this anaesthetic may prove a useful alternative to unanaesthetized preparations.10. The systemic injection of small quantities of thiopentone sodium selectively and reversibly reduced the sensitivity of some units to excitation by 5-HT at a time when the response to glutamate was unaffected. On other occasions, the 5-HT excitation was unaffected, though the response to glutamate was reduced.11. These results are discussed in relation to the possible nature of the 5-HT receptors in the cerebral cortex, and the interfering effects of anaesthesia on the response of brain cells to potential transmitter substances.

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The responsiveness of individual hypothalamic neurons to microelectrophoretically administered endogenous amines

Cited by 89 publications

References 25 publications

Localization of beta-adrenergic receptors on differentiated cells of the central nervous system in culture.

Localization of beta-adrenergic receptors on differentiated cells of the central nervous system in culture.

The inhibitory action of noradrenaline and other monoamines on spinal neurones

Excitation and depression of cortical neurones by 5‐hydroxytryptamine

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