scholarly journals Ontogenetic Development of Sensitivity of the Cerebral Cortex to an Antagonist of GABAA Receptor Bicuculline

2018 ◽  
pp. 149-153
Author(s):  
P. MAREŠ ◽  
K. BERNÁŠKOVÁ ◽  
H. KUBOVÁ
Keyword(s):  
Cerebral Cortex ◽  
Gabaa Receptors ◽  
Age Groups ◽  
Reliable Index ◽  
Bicuculline Methiodide ◽  
Implanted Electrodes ◽  
Immature Rats ◽  
Specific Antagonist ◽  
Effect Relation ◽  
Cortical Maturation

Local application of four concentrations of bicuculline methiodide (a specific antagonist of GABAA receptors) was used to study a sensitivity of somatosensory cortex in four age groups of immature rats with implanted electrodes. Presence and latencies of two epileptic phenomena (focal discharges and seizures) were evaluated. Focal discharges exhibited moderate tendency to a decrease of sensitivity to bicuculline methiodide with maturation. Concentration-effect relation of incidence of focal discharges was observed only in 7- and 12-day-old but not in older animals. Results with incidence and latencies of seizures did not show relations to age or concentration of bicuculline. Neither of the epileptic phenomena can be used as a reliable index of cortical maturation.

EFFECT OF SERUM GONADOTROPHIN ON DEHYDROGENASES OF THE CITRIC ACID CYCLE IN THE OVARY OF THE RAT

1963 ◽  
Vol 42 (4) ◽  
pp. 480-484 ◽  
Author(s):  
B. Eckstein ◽  
R. Landsberg
Keyword(s):  
Citric Acid ◽  
Citric Acid Cycle ◽  
Age Groups ◽  
Succinic Dehydrogenase ◽  
Immature Rat ◽  
Acid Cycle ◽  
Immature Rats ◽  
Rat Ovary

ABSTRACT The succinic, malic and isocitric dehydrogenases in the ovary of immature and mature, normal and serum gonadotrophin injected rats were examined. The Qo2 of these enzymes were markedly enhanced in the gonadotrophin injected rats of both age groups, except in the case of succinic dehydrogenase in the ovary of the immature rats, where a slight non-significant decrease was noted. It is concluded that in the mature rat ovary, gonadotrophin administration stimulates the activity of all the examined dehydrogenases of the citric acid cycle, whereas in the immature rat ovary, at least the isocitric- and malic dehydrogenases are thus stimulated.

Multiple Saccades Are More Automatic Than Single Saccades

2007 ◽  
Vol 97 (4) ◽  
pp. 3148-3151 ◽  
Author(s):  
Paul van Donkelaar ◽  
Sandy Saavedra ◽  
Marjorie Woollacott
Keyword(s):  
Cerebral Cortex ◽  
Age Groups ◽  
Age Group ◽  
Control Task ◽  
Initial Saccade ◽  
Fixation Control

In this paper, we demonstrate that when a peripheral object is foveated by a sequence of multiple saccades, the initial saccade in the sequence is initiated markedly faster than a single accurate saccade to the same object. We suggest that multiple saccades represent a more automatic form of oculomotor planning that may be the result of a reduced influence from the cerebral cortex. To test this, we compared single and multiple saccade characteristics across development. We find that in contrast to the reduction in the latency of single saccades that is observed across development, the latency of initial saccades in multiple saccade sequences is remarkably stable across all age groups. Moreover, the longer the latency of this initial saccade, the more accurate it is, suggesting that there is a relation between the degree of procrastination and the accuracy of the response. Finally, the frequency with which multiple saccades occurred within each age group was positively correlated with the tendency to generate erroneous saccades during a fixation control task. Taken together, the present data suggest that multiple saccades are generated in a more automatic manner than single saccades.

scholarly journals Positive Allosteric Modulator of mGluR4 PHCCC Exhibits Proconvulsant Action in Three Models of Epileptic Seizures in Immature Rats

2012 ◽  
pp. 619-628 ◽  
Author(s):  
E. SZCZUROWSKA ◽  
P. MAREŠ
Keyword(s):  
Metabotropic Glutamate Receptors ◽  
Rhythmic Activity ◽  
Epileptic Seizures ◽  
Allosteric Modulator ◽  
Anticonvulsant Effect ◽  
Positive Allosteric Modulator ◽  
Adult Rats ◽  
Absence Seizures ◽  
Implanted Electrodes ◽  
Immature Rats

The activation of metabotropic glutamate receptors subtype 4 (mGluR4) potentiates models of absence seizures in adult rats. These seizures are age-dependent, but data concerning the role of mGluR4 in immature brain is insufficient. N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1acarboxamide (PHCCC), which is a positive allosteric modulator of these receptors, was used in three different models of seizures in immature rats: 1) convulsions induced by high doses of pentetrazol (PTZ; a model of generalised tonic-clonic seizures); 2) rhythmic electro-encephalographic (EEG) activity induced by low doses of PTZ (a model of absence seizures); and 3) electrically elicited cortical afterdischarges (ADs, a model of myoclonic seizures). We administered four doses of PHCCC (1, 3, 10 and 20 mg/kg) in PTZ-induced convulsions and two doses (3 and 10 mg/kg) in the two electrophysiological models of freely moving rats with implanted electrodes. Every dose and age group consisted from 8 to 10 rats. PTZ-elicited convulsions were not significantly influenced by PHCCC. In contrast, PHCCC potentiated the effect of a subconvulsant dose (60 mg/kg) of PTZ. The 10-mg/kg dose of PHCCC significantly prolonged the duration of PTZ-induced rhythmic activity episodes and shortened the intervals between individual episodes in 25-day-old rats (P25). In contrast, this potentiation was not seen in P18 rats. Cortical ADs were significantly prolonged with repeated stimulations by both doses of PHCCC in P12 and P18 animals. P25 rats exhibited only slightly longer AD durations. In conclusion, we did not find any anticonvulsant effect of PHCCC. On the contrary, proconvulsant action was demonstrated in all three models in immature rats.

THE ANATOMICAL AND PHYSIOLOGICAL EFFECTS OF PRENATALLY ADMINISTERED SOMATOTROPHIN ON CEREBRAL DEVELOPMENT IN RATS

1961 ◽  
Vol 22 (2) ◽  
pp. 183-193 ◽  
Author(s):  
B. G. CLENDINNEN ◽  
J. T. EAYRS
Keyword(s):  
Cerebral Cortex ◽  
Experimental Treatment ◽  
Physiological Effects ◽  
Pregnant Rats ◽  
Statistical Probability ◽  
Cerebral Development ◽  
Pituitary Growth Hormone ◽  
Abnormal Response ◽  
The Brain ◽  
Cortical Maturation

SUMMARY 1. Purified anterior pituitary growth hormone has been given to pregnant rats and a study made of the cerebral development of the young in terms of behaviour, electrical activity of the brain and the quantitative histology of the cerebral cortex. 2. The experimental treatment resulted in an increase in the size of the young at birth. The maturation of innate and reflex behavioural responses was little affected but the performance of cortically mediated behaviour was enhanced. Little significant change was observed in the electroencephalogram other than an abnormal response to photic stimulation. 3. These physiological effects were associated with a modified pattern of cortical maturation consistent with a hypertrophy of neurones. This was reflected in an enlargement of the perikarya and an expansion of protoplasmic processes resulting in an increase in the statistical probability of interaction between neurones. 4. The results are discussed in relation to the earlier and somewhat dissimilar findings reported by Zamenhof (1942), and are regarded as consistent with previously formulated hypotheses linking the structure of the cerebral cortex with its mode of functioning.

Antioxidant enzymes in cerebral cortex of immature rats following experimentally‐induced seizures: upregulation of mitochondrial MnSOD (SOD2)

2012 ◽  
Vol 31 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Jaroslava Folbergrová ◽  
Pavel Ješina ◽  
Hana Nůsková ◽  
Josef Houštěk
Keyword(s):  
Cerebral Cortex ◽  
Antioxidant Enzymes ◽  
Immature Rats ◽  
Experimentally Induced

scholarly journals Nicotine and Kainic Acid Effects on Cortical Epileptic Afterdischarges in Immature Rats

2012 ◽  
pp. 537-542
Author(s):  
V. RILJAK ◽  
D. MAREŠOVÁ ◽  
K. JANDOVÁ ◽  
J. POKORNÝ
Keyword(s):  
Kainic Acid ◽  
Age Groups ◽  
Treated Group ◽  
Albino Rats ◽  
Minor Role ◽  
Single Treatment ◽  
Immature Rats ◽  
Wistar Albino Rats ◽  
Epileptic Afterdischarges ◽  
Experimental Group

Aim of the study was to test the effect of nicotine (NIC) and kainic acid (KA) co-treatment in immature rats. Male Wistar albino rats (two different age groups) were chosen for the study. Experiments started on postnatal day (PD) 8 or 21 and animals were treated twice a day for three days with nicotine, fourth day KA was administered. Animals at PD12 (PD25 respectively) were examined electrophysiologically for cortical epileptic afterdischarges (ADs). First cortical ADs in PD12 animals were longer, when compared to PD25 rats (group treated with both substances). Nor NIC or KA treatment affected the length of discharges in PD12 rats. Older experimental group exhibited the shortening of the first ADs (group treated with NIC and KA, compared with groups exposed to single treatment). Few changes were found in KA treated group – 2nd and 4th ADs were shorter when compared with first ADs. These results demonstrate that NIC treatment played minor role in seizure susceptibility of PD12 rats, sensitivity to NIC differs during ontogenesis and subconvulsive dose of KA influenced the length of discharges only in PD25 animals.

scholarly journals Is Impedance a Parameter to be Taken into Account in Spinal Cord Stimulation?

2007 ◽  
Vol 4;10 (7;4) ◽  
pp. 533-540
Author(s):  
David Abejon
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
Pain Treatment ◽  
Energy Requirement ◽  
Age Groups ◽  
Primary Objective ◽  
Intractable Pain ◽  
Perception Threshold ◽  
Implanted Electrodes ◽  
Significant Difference

Background: Over the last few decades, spinal cord stimulation (SCS) has become one of the main treatments in the therapeutic arsenal available to pain treatment units. New stimulation systems have been developed and the indications of neurostimulation have been expanded. The premises for a successful technique remain the same; good patient selection, good surgical technique, and good management of electrical parameters when programming. Design: An observational report. Objectives: The primary objective of the study was to determine the relationship between changes in impedance (R) and energy requirement (E) elicited by changes in patients posture. The postures analyzed were supine (S), sitting (SI), standing (ST), and walking (W). As a second objective, the difference produced in the energy requirement when changing posture was analyzed. Methods: A study was carried out in 70 patients with chronic intractable pain implanted with a neurostimulation system between January 2000 and March 2006. We define the perception threshold (Tp); the discomfort threshold (Td); and the therapeutic threshold (Tt). The amplitude of perception was measured in mA. With the resulting data, the therapeutic range (TR) was determined. After performing all measurements with the patient in the ST position, the neurostimulation system was shut off and the patient maintained in the other position for 5 minutes before performing the measurements. The variables R and E were compared by age groups, sex, implant duration, and the time since implant placement. Patients were divided into groups according to whether the location of the implanted electrodes was cervical or thoracic. The full analysis by age, sex, and implant duration was performed in the cervical and thoracic implant groups. Results: No correlation was found between impedance and posture. When the results for R and E were analyzed by sex and age, no statistical differences were found in any of the values in any position. The analysis of time since implant greater than or less than 6 months did not find differences in the energy requirement, although there was a significant difference in the impedance value when patients were in the S position. No significant differences were observed in the analysis by age groups. Key words: Impedance, posture change, spinal cord stimulation

GABAergic effects on respiratory neuronal discharge during opossum development

1993 ◽  
Vol 264 (2) ◽  
pp. R331-R336
Author(s):  
J. P. Farber
Keyword(s):  
Gabaa Receptors ◽  
Breathing Pattern ◽  
Age Groups ◽  
Neuronal Firing ◽  
Respiratory Neurons ◽  
Gamma Aminobutyric Acid ◽  
Firing Rates ◽  
Medullary Respiratory Neurons ◽  
Expiratory Neurons ◽  
Gabaa Antagonist

Changes in breathing pattern between immature and adult animals could be due in part to changing postsynaptic sensitivity to particular neurotransmitters by respiratory neurons and/or to the fate of these neurotransmitters after release. To probe for such effects, gamma-aminobutyric acid (GABA) and the GABAA antagonist, bicuculline, were pressure injected by micropipette in very small volumes (approximately 25 pl) near identified medullary respiratory neurons in Inactin-anesthetized adult and suckling opossums. At a concentration of 10 mM, GABA induced suppression of respiratory neurons firing in animals from about 3 wk of age (the youngest animals tested) onward, with the largest responses occurring in adults. For those age groups tested with 0.5 and 50 mM GABA, shorter and longer responses, respectively, were observed. Bicuculline increased the discharge of respiratory units at all ages tested, but responses normalized to initial firing rates did not systematically differ between sucklings down to 4 wk of age and adults. Bicuculline also influenced the onset and cessation of firing in both inspiratory and expiratory neurons. Discharge of respiratory neurons in immature suckling opossums is characterized by few spikes and low firing rates with each breath. However, recovery of neuronal firing from an exogenous load of GABA and release of neuronal firing after antagonism of GABAA receptors does not show a developmental pattern that would implicate GABA as the crucial mediator of these effects.

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