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Z Kleinrok M Sieklucka-Dziuba A Sek E Rodziewicz U Latus 《Acta physiologica Polonica》1987,38(6):477-482
In experiments on male Albino-Swiss mice weighing 18-22 g insulin given in doses of 2 i.u./kg caused no change in the time of reaction to pain, while the same dose administered daily for 7 days potentiated the analgesic action of morphine (3 mg/kg s.c.). Glucose caused no change in this effect of insulin. After 14 days of insulin treatment the time of reaction to pain in the animals subjected to the action of morphine returned to its initial value. Twenty-four hours after the last administration of morphine the level of gamma-aminobutyric acid (GABA) was found to be decreased in the animals receiving insulin with glucose. These results suggest that the central action of insulin is dependent not only on hypoglycaemia produced by it, but may be due also to its direct action on the central structures and an indirect action mediated by its effect on other neurotransmitter systems. 相似文献
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R. Cuppini P. Ambrogini S. Sartini C. Bruno D. Lattanzi M. B. L. Rocchi 《Somatosensory & motor research》2013,30(4):279-285
Primary sensory neurons project to motor neurons directly or through interneurons and affect their activity. In our previous paper we showed that intramuscular sprouting can be affected by changing the sensory synaptic input to motor neurons. In this work, motor axon sprouting within a peripheral nerve (extramuscular sprouting) was induced by nerve injury at such a distance from muscle so as not to allow nerve-muscle trophic interactions. Two different procedures were carried out: (1) sciatic nerve crush and (2) sciatic nerve crush with homosegmental ipsilateral L3-L5 dorsal rhizotomy. The number of regenerating motor axons innervating extensor digitorum longus muscle was determined by in vivo muscle tension recordings and an index of their individual conduction rate was obtained by in vitro intracellular recordings of excitatory postsynaptic end-plate potentials in muscle fibers. The main findings were: (1) there are more regenerated axons distally from the lesion than parent axons proximally to the lesion (sprouting at the lesion); (2) sprouting at the lesion was negatively affected by homosegmental ipsilateral dorsal rhizotomy; (3) the number of motor axons innervating extensor digitorum longus muscle extrafusal fibers counted proximally to the lesion increased following nerve injury and regeneration but this did not occur when sensory input was lost. A transient innervation of extrafusal fibers by n motor neurons may explain the increase of motor axons counted proximally to the lesion. 相似文献
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I. Iscla P. D. Arini L. Szczupak 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1999,184(2):233-241
We studied a specific sensory-motor pathway in the isolated leech ganglia. Pressure-sensitive mechanosensory neurons were
stimulated with trains of action potentials at 5–20 Hz while recording the responses of the annulus erector motorneurons that
control annuli erection. The response of the annulus erector neurons was a succession of excitatory postsynaptic potentials
followed by inhibitory postsynaptic potentials. The excitatory postsynaptic potentials had a brief time-course while the inhibitory
postsynaptic potentials had a prolonged time-course that enabled their temporal summation. Thus, the net effect of pressure-sensitive
neuron stimulation on the annulus erector neurons was inhibitory. Both phases of the response were mediated by chemical transmission;
the excitatory postsynaptic potentials were transmitted via a monosynaptic pathway, and the inhibitory postsynaptic potentials
via a polysynaptic one. The pattern of expression of this dual response depended on the field of innervation of the sensory
neuron and it was under the influence of cell 151, a non-spiking interneuron, that could regulate the expression of the hyperpolarization.
The interaction between pressure-sensitive neurons and annulus erector neuron reveals how sensory specificity, connectivity
pattern and regulatory elements interplay in a specific sensory-motor network.
Accepted: 6 November 1998 相似文献
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The induction of heat shock proteins (Hsps) serves not only as a marker for cellular stress but also as a promoter of cell survival, which is especially important in the nervous system. We examined the regulation of the constitutive and stress-induced 70-kD Hsps (Hsc70 and Hsp70, respectively) after sciatic nerve (SN) axotomy in the neonatal mouse. Additionally, the prevention of axotomy-induced SN cell death by administration of several preparations of exogenous Hsc70 and Hsp70 was tested. Immunohistochemistry and Western blot analyses showed that endogenous levels of Hsc70 and Hsp70 did not increase significantly in lumbar motor neurons or dorsal root ganglion sensory neurons up to 24 hours after axotomy. When a variety of Hsc70 and Hsp70 preparations at doses ranging from 5 to 75 microg were applied to the SN stump after axotomy, the survival of both motor and sensory neurons was significantly improved. Thus, it appears that motor and sensory neurons in the neonatal mouse do not initiate a typical Hsp70 response after traumatic injury and that administration of exogenous Hsc/Hsp70 can remedy that deficit and reduce the subsequent loss of neurons by apoptosis. 相似文献
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Reproductive axis response to repeated lipopolysaccharide administration in peripubertal female rats
Nancy Cardoso Pablo Arias Berta Szwarcfarb Osvaldo Ponzo Silvia Carbone Jaime Moguilevsky Pablo Scacchi Roxana María Reynoso 《Journal of physiology and biochemistry》2010,66(3):237-244
Immune system disorders are often accompanied by alterations in the reproductive axis. Several reports have shown that administration of bacterial lipopolysaccharide (LPS) has central inflammatory effects and activates cytokine release in the hypothalamus where the luteinizing hormone releasing hormone (Gn-RH) neurons are located. The present study was designed to investigate the effect of repeated LPS administration on the neuroendocrine mechanisms of control of the reproductive axis in peripubertal female rats (30-day-old rats). With this aim, LPS (50 μg/kg weight) was administered to the animals during 25, 27 and 29 days of age and sacrificed on 30 day of life. Gn-RH, γ?amino butyric acid (GABA) and glutamic acid (GLU), two amino acids involved in the regulation of Gn-RH secretion, hypothalamic content were measured. LH and estradiol serum levels were also determined and the day of vaginal opening examined. The results showed a significant increase in Gn-RH and GLU content (p?<?0.0001), shared by a reduction of GABA one (p?<?0.0001). LH and estradiol serum levels were decreased (p?<?0.01, p?<?0.001) and delay in the day of vaginal opening was also observed in treated animals. Present results show that repeated LPS administration impaired reproductive function, modifying the neuroendocrine mechanisms of control of the axis in peripubertal female rats. 相似文献
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Summary An electron cytochemical technique is described for the localization of GABA-T, the enzyme which degrades the neurotransmitter GABA, in rat cerebellar cortex. The technique allows ultrastructural demonstration of GABA-T activity by the final deposition of an electron dense formazan precipitate at reaction sites, whilst maintaining adequate ultrastructural preservation for recognition of cellular and subcellular structures. Numerous electron dense precipitates are evident as discrete punctate deposits situated mainly in mitochondria of stellate cells, basket cells and astrocytic glial cells; they are also seen in axonal or dendritic profiles at some synaptic junctions. The technique enables the first cytochemical demonstration of the mitochondrial localization of GABA-T activity in nervous tissue to be presented. It establishes that GABA-T is present in supposed GABA neurones, in pre- or post-synaptic endings, or both, of presumed inhibitory synapses and in glial cells which may be associated with these synapses. From this seemingly ubiquitous distribution, functional aspects of GABA-T in these cells is considered. 相似文献
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Objective
To determine clinically related characteristics in patients with pure lower motor neuron (LMN) syndromes, not fulfilling accepted diagnostic criteria, who were likely to respond to intravenous immunoglobulin (IVIg) treatment.Methods
Demographic, clinical, laboratory and neurophysiological characteristics were prospectively collected from patients with undifferentiated isolated LMN syndromes who were then treated with IVIg. Patients were classified as either responders or non-responders to therapy with IVIg based on clinical data and the two groups were compared.Results
From a total cohort of 42 patients (30 males, 12 females, aged 18-83 years), 31 patients responded to IVIg and 11 did not. Compared to patients that developed progressive neurological decline, responders were typically younger (45.8 compared to 56.0 years, P<0.05) and had upper limb (83.9% compared to 63.6%, NS), unilateral (80.6% compared to 45.5%, P<0.05), and isolated distal (54.1% compared to 9.1%, P<0.05) weakness. Patients with predominantly upper limb, asymmetrical, and distal weakness were more likely to respond to IVIg therapy. Of the patients who responded to treatment, only 12.9% had detectable GM1 antibodies and conduction block (not fulfilling diagnostic criteria) was only identified in 22.6%.Conclusions
More than 70% of patients with pure LMN syndromes from the present series responded to treatment with IVIg therapy, despite a low prevalence of detectable GM1 antibodies and conduction block. Patients with isolated LMN presentations, not fulfilling accepted diagnostic criteria, may respond to IVIg therapy, irrespective of the presence of conduction block or GM1 antibodies, and should be given an empirical trial of IVIg to determine treatment responsiveness. 相似文献13.
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Summation was studied by a procedure close to that used in producing a conditioned reflex. Subthreshold electrical stimulation, which gave rise to a dominant focus in the cat motor cortex, was applied after photic stimulation. Under these conditions, summation occurred both when the two stimuli were applied simultaneously and when the weaker stimulus preceded the stronger one by a very short interval (tens of milliseconds). Increased excitability was characteristic of the dominant focus. An excessive increase in excitability weakened the summation reflex. Electrographically, this type of conditioning was reflected in an increase in amplitude of the primary negative wave of the direct cortical response, recorded in the motor area at a distance of 2–3 mm from the stimulation point. It is concluded from analysis of this electrophysiological phenomenon and comparison of the results with data in the literature that different mechanisms are involved in the summation process during different sequences of stimulation ("photic+electrical" and "electrical+photic").Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 1, No. 3, pp. 293–302, November–December, 1969. 相似文献
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Spike responses of area 4 neurons in the projection area of the contralateral forelimb to acoustic stimulation (1 sec), which became the conditioned stimulus after training, and to dropping of the platform beneath the test limb, which served as reinforcing stimulus, were studied in trained and untrained cats. Responses only of those neurons which were activated during a passive movement caused by dropping of the platform were studied. In trained animals the number of these neurons which responded to the conditioned stimulus if a reflex occurred was 100%, and in the absence of conditioned-reflex movements to the conditioned stimulus it was 70%, much greater than the number of neurons responding to the same acoustic stimulus in untrained animals (45%). On peristimulus histograms of responses of the test neuron population in untrained and trained animals to acoustic stimulation (in the absence of movements) only the initial spike response with a latent period of under 50 msec and a duration of up to 100 msec could be clearly distinguished. In the presence of reflex movement multicomponent spike responses were observed: an initial spike response and early and late after-responses linked with performance of conditioned-reflex limb flexion. Early after-responses 100–200 msec in duration, appearing after a latent period of 100–150 msec, were linked to the time of application of the conditioned stimulus, whereas the appearance and duration of late after-responses were determined by the time of onset of conditioned-reflex movement. The magnitude of the neuronal response to reinforcement in trained animals does not depend on the appearance of the conditioned movement.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 17, No. 1, pp. 93–102, January–February, 1985. 相似文献
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Yukio Mano Yuuji Morita Ryuji Tamura Shigeru Morimoto Tetsuya Takayanagi Richard F Mayer 《Journal of electromyography and kinesiology》1993,3(4):245-250
Cortical and spinal root (C8-T1) magnetic stimulation evoked single motor unit potentials in the abductor pollicis brevis and abductor digiti minimi muscles in a patient with chronic motor neuron disease. This patient was unique in that there were few surviving motoneurons in these muscles making it possible to record single motor units. Central motor conduction time was within normal limits. Cortical mapping of motor evoked potentials (MEPs) was carried out using a twin magnetic coil stimulating over the motor cortex at intervals of 1 cm along the coronal axis and 1–2 cm along the sagittal axis. As the site of cortical stimulation was moved from the centre, the latency of the MEPs increased by 0.7–0.8 ms suggesting one synaptic delay. This study provides further data that magnetic stimulation of the human cortex indirectly activates pyramidal cells via interneurons. 相似文献
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B Neumcke 《Journal de physiologie》1981,77(9):1135-1138
Differences in the electrophysiological properties of amphibian motor and sensory nerve fibres are reviewed. It is concluded that the differences are mainly due to an altered K-conduction system which suggests the presence of different K channels in the two types of nerve fibres. 相似文献
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Recent recordings from spinal neurons in hatchling frog tadpoles allow their type-specific properties to be defined. Seven
main types of neuron involved in the control of swimming have been characterized. To investigate the significance of type-specific
properties, we build models of each neuron type and assemble them into a network using known connectivity between: sensory
neurons, sensory pathway interneurons, central pattern generator (CPG) interneurons and motoneurons. A single stimulus to
a sensory neuron initiates swimming where modelled neuronal and network activity parallels physiological activity. Substitution
of firing properties between neuron types shows that those of excitatory CPG interneurons are critical for stable swimming.
We suggest that type-specific neuronal properties can reflect the requirements for involvement in one particular network response
(like swimming), but may also reflect the need to participate in more than one response (like swimming and slower struggling).
Action Editor: Eberhard E. Fetz 相似文献