THE EFFECTS OF CONVULSANT AGENTS ON PARTIALLY ISOLATED REGIONS OF THE CENTRAL NERVOUS SYSTEM

1956 ◽  
Vol 34 (4) ◽  
pp. 689-712 ◽  
Author(s):  
C. G. Drake ◽  
J. J. Seguin ◽  
G. W. Stavraky

The effects of removal of one motor cortex, a frontal lobe, or a complete cerebral hemisphere on the action of various convulsant agents were studied in chronic cats and in spinal preparations. In both sets of experiments, previously decentralized neurons responded to smaller quantities of convulsant drugs than did the intact ones, and pentylenetetrazol, camphor, and picrotoxin, as well as strychnine and acetylcholine, evoked greater and more prolonged responses from these neurons when sufficient time was allowed for sensitization due to partial isolation to take place (in the majority of experiments two to eight months).This was ascertained in myographic recordings and in studies of the electrical activity of the anterior horn cells in high spinal cats and white rats, as well as in photographic and statistical analyses of convulsions induced in chronic animals. The latter study revealed that the convulsions were asymmetrical in the operated cats, the muscular contractions being exaggerated and prolonged contralaterally to the cerebral ablation. The median convulsant dose (CD50) of pentylenetetrazol for the control cats was 7.8 mgm./kgm. (95% confidence limits 7.4–8.1) while that for the operated group was 6.8 mgm./kgm. (95% confidence limits 6.3–7.2). The latent period following the injection of pentylenetetrazol was significantly shorter for the operated group than for the control one, and the convulsions lasted longer in the operated cats than in intact animals. The longer duration of convulsions in the operated group depended on a significantly longer tonic and terminal clonic phase of the convulsion. Two patterns of convulsions could be elicited—a clonic and a more severe clonic–tonic–clonic (CTC) one. In the control group clonic convulsions were more frequent at low dosages of pentylenetetrazol while CTC convulsions pre-dominated at high dosages. In the operated group CTC convulsions were prevalent throughout the range of doses used and occurred in a greater percentage of animals than in the control group. Chemically induced convulsions play a prominent part in the study of epilepsy and in the treatment of some mental derangements, and it is felt that this investigation may contribute to the understanding of the mechanism of action of convulsant agents on the nervous system in which abnormal conditions prevail.

1956 ◽  
Vol 34 (1) ◽  
pp. 689-712 ◽  
Author(s):  
C. G. Drake ◽  
J. J. Seguin ◽  
G. W. Stavraky

The effects of removal of one motor cortex, a frontal lobe, or a complete cerebral hemisphere on the action of various convulsant agents were studied in chronic cats and in spinal preparations. In both sets of experiments, previously decentralized neurons responded to smaller quantities of convulsant drugs than did the intact ones, and pentylenetetrazol, camphor, and picrotoxin, as well as strychnine and acetylcholine, evoked greater and more prolonged responses from these neurons when sufficient time was allowed for sensitization due to partial isolation to take place (in the majority of experiments two to eight months).This was ascertained in myographic recordings and in studies of the electrical activity of the anterior horn cells in high spinal cats and white rats, as well as in photographic and statistical analyses of convulsions induced in chronic animals. The latter study revealed that the convulsions were asymmetrical in the operated cats, the muscular contractions being exaggerated and prolonged contralaterally to the cerebral ablation. The median convulsant dose (CD50) of pentylenetetrazol for the control cats was 7.8 mgm./kgm. (95% confidence limits 7.4–8.1) while that for the operated group was 6.8 mgm./kgm. (95% confidence limits 6.3–7.2). The latent period following the injection of pentylenetetrazol was significantly shorter for the operated group than for the control one, and the convulsions lasted longer in the operated cats than in intact animals. The longer duration of convulsions in the operated group depended on a significantly longer tonic and terminal clonic phase of the convulsion. Two patterns of convulsions could be elicited—a clonic and a more severe clonic–tonic–clonic (CTC) one. In the control group clonic convulsions were more frequent at low dosages of pentylenetetrazol while CTC convulsions pre-dominated at high dosages. In the operated group CTC convulsions were prevalent throughout the range of doses used and occurred in a greater percentage of animals than in the control group. Chemically induced convulsions play a prominent part in the study of epilepsy and in the treatment of some mental derangements, and it is felt that this investigation may contribute to the understanding of the mechanism of action of convulsant agents on the nervous system in which abnormal conditions prevail.


2018 ◽  
Vol 17 (2) ◽  
pp. 132-143 ◽  
Author(s):  
Mehmet Eray Alcigir ◽  
Halef Okan Dogan ◽  
Begum Yurdakok Dikmen ◽  
Kubra Dogan ◽  
Sevil Atalay Vural ◽  
...  

Background & Objective: Aroclor 1254 is a widespread toxic compound of Polychlorinated Biphenyls (PCBs), which can create significant nervous problems. No remedies have been found to date. The aim of this study was to reveal the damage that occurs in the central nervous system of rat pups exposed to Aroclor 1254 in the prenatal period and to show the inhibiting effect of curcumin, which is a strong anti-oxidant and neuroprotective substance. Method: The study established 3 groups of adult female and male Wistar albino rats. The rats were mated within these groups and the offspring rats were evaluated within the group given Aroclor 1254 only (n=10) and the group was given both Aroclor 1254 and curcumin (n=10) and the control group (n=10). The groups were compared in respect of pathomorphological damage. The immunohistochemical evaluation was made of 8-hydroxdeoxyguanosine (8-OHdG), 4-hydroxynoneal (4HNE), myelin basic protein (MBP) expressions and TUNEL reaction. The biochemical evaluation was made of the changes in the TAS-TOS and Neuron Specific Enolase (NSE) levels. Damage was seen to have been reduced with curcumin in the 8OHdG and TUNEL reactions, especially in the forebrain and the midbrain, although the dosage applied did not significantly change TAS and TOS levels. Consequently, it was understood that Aroclor 1254 caused damage in the central nervous system of the pup in the prenatal period, and curcumin reduced these negative effects, particularly in the forebrain and the midbrain. Conclusion: It was concluded that curcumin could be a potential neuroprotective agent and would be more effective at higher doses.


2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Qianli Tang ◽  
Qiuyan Jiang ◽  
Suren R. Sooranna ◽  
Shike Lin ◽  
Yuanyuan Feng ◽  
...  

To observe the effects of electroacupuncture on pain threshold of laboring rats and the expression of norepinephrine transporter andα2 adrenergic receptor in the central nervous system to determine the mechanism of the analgesic effect of labor. 120 pregnant rats were divided into 6 groups: a control group, 4 electroacupuncture groups, and a meperidine group. After interventions, the warm water tail-flick test was used to observe pain threshold. NE levels in serum, NET, andα2AR mRNA and protein expression levels in the central nervous system were measured. No difference in pain threshold was observed between the 6 groups before intervention. After intervention, increased pain thresholds were observed in all groups except the control group with a higher threshold seen in the electroacupuncture groups. Serum NE levels decreased in the electroacupuncture and MP groups. Increases in NET andα2AR expression in the cerebral cortex and decreases in enlarged segments of the spinal cord were seen. Acupuncture increases uptake of NE via cerebral NET and decreases its uptake by spinal NET. The levels ofα2AR are also increased and decreased, respectively, in both tissues. This results in a decrease in systemic NE levels and may be the mechanism for its analgesic effects.


2021 ◽  
Vol 11 (11) ◽  
pp. 249-265
Author(s):  
B. Lobasyuk ◽  
L. Bartsevich ◽  
A. Zamkovaya

Justification. Mental retardation is a persistent decrease in human cognitive activity against the background of organic damage to the central nervous system. Neurophysiological diagnostics, in particular electroencephalography (EEG), most adequately reflects the morpho-functional state of the central nervous system, which is the basis of the mechanisms of mental activity, and the originality of the bioelectrical activity of the brain can be considered as the main indicator that determines a decrease in the level of intellectual development and, thereby, characterizes this state. This provision actualizes the search for highly informative indicators of the originality of the bioelectrical activity of the brain in children with intellectual disabilities. Purspose. With the use of periodometric analysis investigate EEG’s indicators and interhemispheric asymmetry of rhythms amplitudes in MR patients. Materials and methods. The EEG was recorded in a state of calm wakefulness with closed eyes with Neuron-Spectrum-2 electroencephalograph. Differences in indicators were tracked using the calculation of the coefficient of compliance (CC), EEG functional asymmetry coefficients in amplitude were determined, too. Results. It was revealed that in MR patients the amplitudes of the rhythms were greater than in healthy subjects. The greatest increase was determined in theta rhythm in the anterior temporal and posterior temporal leads in the left hemispheres. Duration indices in the delta, theta and alpha ranges of the EEG in mental retardation compared with the control group were increased, and the indices of the duration of beta rhythms - decreased. When analyzing FMPA in MR persons it turned out that in right-handers the negativeness of FMPA indices increased, and in left-handers there was an increase in the positivity of FMPA indices. Conclusions 1. With mental retardation, the amplitudes of the rhythms were greater than in healthy people. The greatest increase was determined in theta rhythm in the anterior temporal and posterior temporal leads in the left hemispheres. 2. The indices of duration in the delta, theta and alpha ranges of the EEG of MR subjects were increased, and the indices of the duration of beta rhythms – decreased. 3. When analyzing FMPA in MR persons, it turned out that in right-handers the negativeness of FMPA indices increased, and in left-handers there was an increase in the positivity of FMPA indices.


1998 ◽  
Vol 17 (3) ◽  
pp. 231-275 ◽  
Author(s):  
Marciavan Gemert ◽  
James Killeen

The diverse, structurally unrelated chemicals that cause toxic myelinopathies have been investigated and can be categorized into two types of primary demyelinators. Some demyelinating chemicals seem to leave intact the myeli-nating cells (oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system), while others damage the myelinating cells as well as the myelin. The significance between the two is that with the myelinating cells still in tact, repair of the myelin sheath can occur. However, if the myelinating cells are destroyed, repair and reversal of the neuropathy may not occur. Histologically, these chemicals produce an edema of the white matter of the brain, and in some cases the peripheral nervous system, that appears spongy by light microscopy. By electron microscopy, vacuoles can be seen in the myelin surrounding axons. These vacuoles are characterized as fluid-filled separations (splitting) of myelin lamellae at the intraperiod line. In some cases these vacuoles can degenerate further to full demyelination, affecting conduction through those axons. Regeneration of the myelin layers can occur, and in some cases occurs at the same time other axons are undergoing toxic demyelination. Several of these chemicals, however, have been shown to increase cerebrospinal fluid pressure in the brain, optic nerve, and spinal cord, and/or intraneuronal pressure in the perineurium surrounding the axons in the peripheral nervous system. This increased pressure has been correlated with decreased conduction capacity through the axon, ischemia to the neuronal tissue from decreased blood flow because of pressure against the blood vessels, and, if unrelieved, permanent axonal damage. Several of these chemicals havebeen shown to inhibit oxidative phosphorylation, while others uncouple oxidative phosphorylation. One chemical appears to inhibit an enzyme critical to cholesterol synthesis, thus destabilizing myelin. Another hypothesis for a mechanism of action may be in the ability of these compounds to alter membrane permeability.


2021 ◽  
Vol 5 (6) ◽  
pp. 16-19
Author(s):  
Chunpeng Wang ◽  
Xiaohui Liu ◽  
Shiwen Guo

Objective: The purpose of this study is to explore the role of sphingosine kinase 2 (SphK2) in the treatment of glioma, which is the most common primary tumor in the central nervous system. Methods: A total of 82 patients were included in this study, with 27 cases in the control group and 55 cases in the glioma group; the expressions of SphK2 and gp130 in the two groups were compared by immunohistochemical method, and the correlation between the two factors was analyzed. Results: Both SphK2 and gp130 were upregulated in the glioma group, and the two factors were significantly correlated. Conclusion: The high expression of SphK2 may play an important role in the occurrence, development, and diagnosis of glioma.


2019 ◽  
Vol 19 (1S) ◽  
pp. 68-70
Author(s):  
N A Didkovsky ◽  
I K Malashenkova ◽  
D P Ogurtsov ◽  
S A Krynskiy ◽  
N A Hailov ◽  
...  

The aim of the work is to study the level of systemic inflammation and changes in adaptive immunity in the early period after acute psychosis to assess their participation in the pathogenesis of alcoholic mental and cognitive disorders. We examined 28 patients with alcoholic psychosis (AP) and a control group of 17 healthy volunteers. Indicators of systemic inflammation and immunity, including key cytokines and lymphocyte subpopulations, were investigated. After acute psychosis of patients with alcoholism, pronounced activation of humoral immunity with impaired clearance of immune complexes, increased content and activity of Th2 with signs of insufficiency and dysfunction of Th1, reduced content and activity of cytotoxicity system cells and signs of systemic inflammation (increased CRP, cortisol, cytokines). Activation of Th2 response and an excess of proinflammatory mediators in patients with AP through various ways of interaction with the Central nervous system (n. vagus, choroidal plexus of the ventricles, and others) can participate in the disorders of metabolism of neurotransmitters in the Central nervous system involved in the pathogenesis of alcoholism, and in the maintenance of neuroinflammation. A high level of systemic inflammation can be both a trigger of psychosis and a manifestation of violations of neuroimmune interactions, as well as the development of excitotoxicity and damage to neurons in acute psychosis.


2015 ◽  
Vol 26 (1) ◽  
pp. 50-53

Multiple sclerosis is the most common demyelinating disease of the central nervous system, affecting mostly young people. There were many risk factors for MS identified, however a direct cause of the disease is still unknown. Pathological changes in the SM lead to the myelin sheath damage around axons, what prevents proper transmission of nerve impulses in the central nervous system. The aim of this study was analyzing and comparing the amino acids profile in the blood serum of MS patients to control group of healthy individuals and evaluating the relationship between them. Significant (p<0.05) differences in the level of glutamate, aspartate and taurine in the blood serum of MS patients were revealed. A positive glutamate and aspartate level correlation in the serum has been demonstrated. Gender is significant only in the case of glutamate level in blood serum. The studies highlight the important role of neurotransmitters in MS and are the initial step in proteomic research.


PEDIATRICS ◽  
1974 ◽  
Vol 54 (4) ◽  
pp. 522-522
Author(s):  
Richard J. Schain

The paper by Quinn and Rapoport1 in the May issue of Pediatrics indicates a higher incidence of minor physical anomalies ("stigmata") in hyperactive boys compared to a control group. The authors believe that the presence of stigmata are a clue to the occurrence of insults affecting the fetus during early development. It is suggested that the hyperactive behavior disorder is also a result of the same insult affecting the central nervous system during early morphogenesis.


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