Glucocorticoids are modulators of GABAA receptors in brain

Majewska, Maria Dorota; Bisserbe, J.C.; Eskay, Robert L.

doi:10.1016/0006-8993(85)90641-9

Cited by 184 publications

(51 citation statements)

References 12 publications

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“…In whole hypothalamus preparations several groups showed increased agonist binding to the benzodiazepine receptor complex after ADX. This effect could be reversed by corticosteroid substitution Goeders et al 1986;Majewska et al 1985). Recently, Miklos and Kovacs (2002) found that 7 days after ADX the number of GABAergic terminals specifically on CRH-positive neurons was significantly increased, as established with electron microscopy.…”

Section: Effect Of Adxmentioning

confidence: 92%

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Effect of Adrenalectomy on Miniature Inhibitory Postsynaptic Currents in the Paraventricular Nucleus of the Hypothalamus

Verkuyl

Joëls

2003

Journal of Neurophysiology

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Verkuyl, J. M. and M. Joëls. Effect of adrenalectomy on miniature inhibitory postsynaptic currents in the paraventricular nucleus of the hypothalamus. J Neurophysiol 89: 237-245, 2003; 10.1152/jn.00401.2002. Within the rat paraventricular nucleus of the hypothalamus two types of neurons have been distinguished based on morphological appearance, i.e., parvocellular and magnocellular neurons. The parvocellular neurons play a key role in regulating the activity of the hypothalamo-pituitary-adrenal axis, which is activated, e.g., after stress exposure. These neurons receive humoral negative feedback via the adrenal hormone corticosterone but also neuronal inhibitory input, either directly or transsynaptically relayed via GABAergic interneurons. In the present study we examined to what extent the neuronal GABAergic input is influenced by the humoral signal. To this end, miniature inhibitory postsynaptic currents (mIPSCs) were recorded in parvo-and magnocellular neurons of adrenalectomized rats, which lack corticosterone, and in sham-operated controls. Under visual control neurons in coronal slices containing the paraventricular nucleus were designated as putative parvocellular or magnocellular neurons: the former were located in the medial part of the nucleus and displayed a small fusiform soma; the latter were mostly located in the lateral part and were recognized by their large round soma. Compared with putative magnocellular neurons, parvocellular neurons generally exhibited a lower membrane capacitance, lower mIPSC frequency, and smaller mIPSC amplitude. Following adrenalectomy, the mIPSC frequency was significantly enhanced in parvo-but not magnocellular neurons. Other properties of the cells were not affected. In a second series of experiments we examined whether the increase in mIPSC frequency was due to the absence of corticosterone or caused by other effects related to adrenalectomy. The data support the former explanation since implantation of a corticosterone releasing pellet after adrenalectomy fully prevented the change in mIPSC frequency. We conclude that, in the absence of humoral negative feedback, local GABAergic input of parvocellular neurons in the paraventricular nucleus is enhanced. This may provide a compensatory mechanism necessary for maintaining controllable network activity.

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Section: Effect Of Adxmentioning

confidence: 92%

“…Conversely, removal of the humoral feedback by adrenalec-tomy led to increased benzodiazepine binding, as measured in whole-hypothalamus preparations of the rat. This effect was reversed by corticosteroid substitution Goeders et al 1986;Majewska et al 1985).…”

Section: Introductionmentioning

confidence: 95%

Effect of Adrenalectomy on Miniature Inhibitory Postsynaptic Currents in the Paraventricular Nucleus of the Hypothalamus

Verkuyl

Joëls

2003

Journal of Neurophysiology

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“…The role of stress in the induction of changes in the cortical GABA system in schizophrenia and bipolar disorder is an interesting issue to explore. For example, glucocorticoid hormones have the ability to bind to the GABA A receptor (Sutanto et al 1989) and have been found to directly increase its activity (Majewska et al 1985;Lambert et al 1987). In this regard, it is noteworthy that the binding of [ 3 H]corticosterone is greatest in sector CA2 (McEwen 1982;Stumpf et al 1989) where schizophrenics and bipolars both show a marked decrease of nonpyramidal neurons and also the largest increase of GABA A receptor binding (see above).…”

Section: The Neurodevelopmental Hypothesismentioning

confidence: 98%

GABAergic Interneurons Implications for Understanding Schizophrenia and Bipolar Disorder

Beneš

Berretta

2001

Neuropsychopharmacology

989

643

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Neurons that express the compound, ␥ -aminobutyric acid (GABA), are broadly present throughout the central nervous system, although telencephalic structures, such as the cerebral cortex, show the most abundant quantities of this neurotransmitter (Jones 1987). In the discussion that follows, the anatomy and physiology of various types of GABAergic interneurons in the cortex and hippocampus will be discussed and related to recent postmortem studies implicating this transmitter system in the pathophysiology of schizophrenia and bi- 25 , NO . 1 polar disorder and their treatment with neuroleptic drugs (for more comprehensive reviews on cortical and hippocampal neurons see: Hof et al. 1993;Freund and Buzsaki 1996;Somogyi et al. 1998). NEUROBIOLOGY OF GABAERGIC INTERNEURONSBased on Golgi-impregnation studies, Ramon y Cajal provided the first descriptions of several different morphological subtypes of interneurons in the cerebral cortex and hippocampus (Ramon y Cajal 1893, 1911. In more recent years, it has been shown that, with some overlap, different morphological subtypes also have distinct distributions, connectivity, neurochemistry, and electrophysiological properties (for reviews see Hof et al. 1993;Freund and Buzsaki 1996). It is interesting to note that every segment of a pyramidal neuron, such as the soma, dendritic branches and spines, and the initial axonal segment, receives dense GABAergic synaptic innervation (O'Kusky and Colonnier 1982;Hendry et al. 1983;Houser et al. 1983; Beaulieu et al. 1992; for reviews see Jones 1993;Freund and Buzsaki 1996). Even more interestingly, each of these segments appears to be innervated by distinct GABAergic neuronal subtypes (see below).These differences strongly suggest that each of these subtypes plays a fundamentally different role in physiological and pathological mechanisms. In the discussion that follows, cortical interneurons will be described first, since our most basic understanding of GABAergic cells is derived from these populations. In more recent years, however, similar characterizations of interneurons in hippocampus have emerged. Although these cells show some striking similarities to their cortical counterparts, there are also some unique features that distinguish them. For this reason, interneurons in the hippocampus are discussed separately. Cortex Neuroanatomical Studies of Cortical Interneurons.Various types of GABAergic neurons can be categorized according to the type of synaptic profiles they are associated with, as this has direct implications for understanding the physiological role of these cells in cortical circuits. These categories are discussed below.A XO -S OMATIC I NHIBITORY S YNAPSES (B ASKET C ELLS ). The most commonly encountered interneurons ( Figure 1A) are multipolar in shape, i.e., they may have three or more primary dendritic branches emanating from their cell bodies, some having somata that are as large as those of pyramidal neurons (Jones and Hendry 1984). Using immunocytochemistry to localize the enzyme ). These cells also ...

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“…Adrenalectomy generally increases binding of benzodiazepines, GABA or muscimol in striatum, midbrain (Kendall et al, 1982), cortex (Acuna et al, 1990) and hypothalamus (Majewska et al, 1985;DeSouza et al, 1986). However, the latter may be secondary to a rise in ACTH levels after ADX (Kendall et al, 1982;DeSouza et al, 1986).…”

Section: Inhibitory Amino Acids'mentioning

confidence: 99%

Mineralocorticoid and glucocorticoid receptors in the brain. Implications for ion permeability and transmitter systems

Joëls

Kloet

1994

Progress in Neurobiology

368

168

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Glucocorticoids are modulators of GABAA receptors in brain

Cited by 184 publications

References 12 publications

Effect of Adrenalectomy on Miniature Inhibitory Postsynaptic Currents in the Paraventricular Nucleus of the Hypothalamus

Effect of Adrenalectomy on Miniature Inhibitory Postsynaptic Currents in the Paraventricular Nucleus of the Hypothalamus

GABAergic Interneurons Implications for Understanding Schizophrenia and Bipolar Disorder

Mineralocorticoid and glucocorticoid receptors in the brain. Implications for ion permeability and transmitter systems

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