Neurochemical aspects of the ontogenesis of gabanergic neurons in the rat brain

Coyle, Joseph T.; Enna, S.J.

doi:10.1016/0006-8993(76)91053-2

Cited by 369 publications

(142 citation statements)

References 31 publications

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Section: Discussionmentioning

confidence: 99%

“…Total brain concentration of GABA is 50% of adult levels at birth, while adult concentrations are found in the brainstem and cerebellum 4,8 . GABA uptake is at adult levels at birth 20 , while the activity of glutamic acid decarboxylase, the GABA synthetic enzyme is only 5% of adult levels 4 . GABA-receptor activity is present at 25%-33% of adult binding at birth and throughout the first postnatal days, and increases to adult levels by the fourth week 4,20 .…”

Section: Discussionmentioning

confidence: 99%

“…GABA uptake is at adult levels at birth 20 , while the activity of glutamic acid decarboxylase, the GABA synthetic enzyme is only 5% of adult levels 4 . GABA-receptor activity is present at 25%-33% of adult binding at birth and throughout the first postnatal days, and increases to adult levels by the fourth week 4,20 . Electrophysiologic studies demonstrated the opening of chloride channels by GABA in cultured astrocytes derived from 0-2 day old rats 10 .…”

Section: Discussionmentioning

confidence: 99%

“…Immunocytochemical 13 and biochemical 4,5 studies suggest that the γ-aminobutyric acid (GABA) neuronal system of the rat may mature relatively early. Thus, pharmacological manipulation of GABA neurotransmission may allow the generation of seizure paradigms useful in the immediately postnatal rat, when many conventional convulsants are not applicable 24,25 .…”

Section: Introductionmentioning

confidence: 99%

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Bicuculline induced seizures in infant rats: ontogeny of behavioral and electrocortical phenomena

Baram

Snead

1990

Developmental Brain Research

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The effects of bicuculline, a γ-aminobutyric acid (GABA) antagonist, were investigated in 258 immature rats between the third and 22nd postnatal days. Behavioral and electrocorticographic events were correlated. Bicuculline induced both behavioral and electrographic seizures as early as the third postnatal day, an age when the CD 50 for bicuculline was lowest, and therefore the sensitivity to it was the greatest. Bicuculline may thus be a suitable convulsant for epilepsy studies involving rats during the first postnatal week.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Bicuculline induced seizures in infant rats: ontogeny of behavioral and electrocortical phenomena

Baram

Snead

1990

Developmental Brain Research

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“…Thus other factors must influence the control exerted by opioids on the hypothalamus-pituitary-adrenal axis. It is unlikely to be related to immaturity of other intermediary neurochemical systems involved in control of ACTH since, like opioid systems, these develop rapidly in the early postnatal period (Coyle & Enna, 1976;Nomura et al, 1976 …”

Section: Discussionmentioning

confidence: 99%

Developmental responses to opioids reveals a lack of effect on stress‐induced corticosterone levels in neonatal rats

Bailey

Kitchen

1987

British J Pharmacology

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1 The neonate has an unusual capacity for survival and the possibility exists that mechanisms for controlling stress responses may differ in the developing animal. In adults both endogenous and exogenous opioids can modulate the corticosterone responses to stress. We have studied this effect in neonatal rats and found that opioid modulation is absent in early postnatal development.2 Neonatal rats ofeither sex were injected with morphine (5-50mg kg-'), fentanyl (10-100 .tLg kg-'), buprenorphine (O.1-30 mg kg') or naloxone (O.1-Omg kg-') and plasma corticosterone measured fluorimetrically 15 or 20 min later. In addition naloxone reversibility studies (1 mg kg-', co-administered) were carried out for the opioid agonists. 3 In adult rats, elevations in plasma corticosterone caused by injection stress were potentiated by morphine, fentanyl and buprenorphine. In neonates, though injection stress-induced rises in plasma corticosterone were absent at 10 days, elevations were observed at 21 days and later. However, significant potentiation of this corticosterone response by fentanyl was absent at 21 days and at later ages (30 and 40 days) for morphine and buprenorphine. The potentiating effect of all three agonists did not become fully effective until day 45. In addition, in animals acclimatized to injection stress by 7 day injection pretreatment, fentanyl did not significantly alter corticosterone levels in 30 day old neonates.4 High doses ofnaloxone (10mg kg-')significantly increased the corticosterone response to injection stress in adult rats but this effect was absent in 30 day old animals. A dose of naloxone (I mg kg-') which had no significant effect on the corticosterone response inhibited the effects of morphine, fentanyl and buprenorphine in 45 day old and adult rats. 5 This late development of opioid action is unusual in comparison with the maturation of endogenous peptides, receptors and antinociceptive responses and suggests that alternative mechanisms may be involved in stress-control in the neonate.

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Differences in the subregional and cellular distribution of GABAA receptor binding in the hippocampal formation of schizophrenic brain

Beneš

Khan

Vincent

et al. 1996

Synapse

144

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Recent postmortem studies have reported a marked upregulation of GABAA receptor binding activity in the anterior cingulate and prefrontal cortices of schizophrenic subjects. Because the hippocampal formation is a key corticolimbic region that has also been implicated by both postmortem and brain imaging studies in the pathophysiology of this disorder, the current report has sought to determine whether alterations of GABAA receptor binding might also be detected in this region from 15 normal controls and 8 schizophrenic subjects. Using a low resolution autoradiographic approach, the results show a significant increase of specific GABAA receptor binding activity in the area dentata (granule cell layer), CA4, CA3 (str. oriens, str. pyramidale), subiculum, and presubiculum of the schizophrenic group. The magnitude of the increase was greatest in CA3 and lowest in the CA1 sector. When high resolution analyses were performed on emulsion‐coverslip preparations, a modest increase of binding (43%, P = 0.05) was observed on pyramidal, but not non‐pyramidal neurons in sector CA1. Rather unexpectedly, GABAA binding in sector CA3 was not significantly different on pyramidal cells, but was almost three‐fold higher (P = 0.015) on non‐pyramidal neurons of the schizophrenic group. There was no relationship of age or the postmortem interval to the parameters showing significant changes in the schizophrenic group. Moreover, patients both with and without neuroleptic exposure showed upregulation of GABAA receptor binding activity. Taking together the rather modest increase of binding activity in CA1 and the more marked upregulation in CA3, as well as the differential changes on pyramidal neurons of CA1 vs. non‐pyramidal neurons in CA3, the findings reported here are consistent with the possibility that a disturbance of brain development could have occurred either perinatally or perhaps even well into the postnatal period, and have given rise to discreet subregional and cellular alterations of disinhibitory GABAergic modulation in sector CA3 of schizophrenics. Overall, the data reported here provide further evidence that alterations of GABAergic activity may occur in the hippocampal formation of schizophrenic patients. © 1996 Wiley‐Liss, Inc.

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Neurochemical aspects of the ontogenesis of gabanergic neurons in the rat brain

Cited by 369 publications

References 31 publications

Bicuculline induced seizures in infant rats: ontogeny of behavioral and electrocortical phenomena

Bicuculline induced seizures in infant rats: ontogeny of behavioral and electrocortical phenomena

Developmental responses to opioids reveals a lack of effect on stress‐induced corticosterone levels in neonatal rats

Differences in the subregional and cellular distribution of GABAA receptor binding in the hippocampal formation of schizophrenic brain

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