共查询到20条相似文献，搜索用时 31 毫秒
1.
Tetrodotoxin: effects on fish and frog melanophores 总被引：1，自引：0，他引：1
Tetrodotoxin blocks the response of killifish melanophores to electrical stimulation of their melanin-aggregating nerves. The direct response of killifish or frog melanophores to hormones is not affected. Since there is no effect on melanin aggregation resulting from the release of adrenergic neurotransmitter in killifish melanophores, we conclude that tetrodotoxin acts by blocking nerve conduction. 相似文献
2.
The response of single units in cuneate and gracile nuclei to cutaneous stimulation can be modified by prior stimulation of the motor cortex of the cat. Both excitation and inhibition of these neurons can be effected via the pyramidal tract. 相似文献
3.
Acquisition by innervated cardiac myocytes of a pertussis toxin-specific regulatory protein linked to the alpha 1-receptor 总被引：4，自引：0，他引：4
S F Steinberg E D Drugge J P Bilezikian R B Robinson 《Science (New York, N.Y.)》1985,230(4722):186-188
During development, the chronotropic response of rat ventricular myocardium to alpha 1-adrenergic stimulation changes from positive to negative. The alpha 1-agonist phenylephrine increases the rate of contraction of neonatal rat myocytes cultured alone but decreases the rate of contraction when the myocytes are cultured with functional sympathetic neurons. The developmental induction of the inhibitory myocardial response to alpha 1-adrenergic stimulation in intact ventricle and in cultured myocytes was shown to coincide with the functional acquisition of a substrate for pertussis toxin. A 41-kilodalton protein from myocytes cultured with sympathetic neurons and from adult rat myocardium showed, respectively, 2.2- and 16-fold increases in pertussis toxin-associated ADP-ribosylation (ADP, adenosine diphosphate) as compared to controls. In nerve-muscle cultures, inhibition of the actions of this protein by pertussis toxin-specific ADP-ribosylation reversed the mature inhibitory alpha 1-adrenergic response to an immature stimulatory pattern. The results suggest that innervation is associated with the appearance of a functional pertussis toxin substrate by which the alpha 1-adrenergic response becomes linked to a decrease in automaticity. 相似文献
4.
Electrophysiologic responses in hamster superior colliculus evoked by regenerating retinal axons 总被引：7，自引：0，他引：7
S A Keirstead M Rasminsky Y Fukuda D A Carter A J Aguayo M Vidal-Sanz 《Science (New York, N.Y.)》1989,246(4927):255-257
Autologous peripheral nerve grafts were used to permit and direct the regrowth of retinal ganglion cell axons from the eye to the ipsilateral superior colliculus of adult hamsters in which the optic nerves had been transected within the orbit. Extracellular recordings in the superior colliculus 15 to 18 weeks after graft insertion revealed excitatory and inhibitory postsynaptic responses to visual stimulation. The finding of light-induced responses in neurons in the superficial layers of the superior colliculus close to the graft indicates that axons regenerating from axotomized retinal ganglion cells can establish electrophysiologically functional synapses with neurons in the superior colliculus of these adult mammals. 相似文献
5.
R A Gillis 《Science (New York, N.Y.)》1969,166(904):508-510
A study of the effects of ouabain and propranolol on the spontaneous activity in the preganglionic sympathetic nerves to the cat heart showed that ouabain can produce both an inhibition and a stimulation of the spontaneous activity in sympathetic nerves. The inhibition appears to be reflex in nature and is not present when the buffer nerves are sectioned. The stimulation is correlated with the development of cardiac arrhythmias and is antagonized by propranolol. 相似文献
6.
Decreased hippocampal inhibition and a selective loss of interneurons in experimental epilepsy 总被引：46，自引：0，他引：46
R S Sloviter 《Science (New York, N.Y.)》1987,235(4784):73-76
The occurrence of seizure activity in human temporal lobe epilepsy or status epilepticus is often associated with a characteristic pattern of cell loss in the hippocampus. An experimental model that replicates this pattern of damage in normal animals by electrical stimulation of the afferent pathway to the hippocampus was developed to study changes in structure and function that occur as a result of repetitive seizures. Hippocampal granule cell seizure activity caused a persistent loss of recurrent inhibition and irreversibly damaged adjacent interneurons. Immunocytochemical staining revealed unexpectedly that gamma-aminobutyric acid (GABA)-containing neurons, thought to mediate inhibition in this region and predicted to be damaged by seizures, had survived. In contrast, there was a nearly complete loss of adjacent somatostatin-containing interneurons and mossy cells that may normally activate inhibitory neurons. These results suggest that the seizure-induced loss of a basket cell-activating system, rather than a loss of inhibitory basket cells themselves, may cause disinhibition and thereby play a role in the pathophysiology and pathology of the epileptic state. 相似文献
7.
Noradrenergic stimulation of cyclic adenosine monophosphate in rat Purkinje neurons: an immunocytochemical study 总被引：4，自引：0，他引：4
G R Siggins E F Battenberg B J Hoffer F E Bloom A L Steiner 《Science (New York, N.Y.)》1973,179(73):585-588
A specific immunofluorescent histochemical method for cyclic adenosine monophosphate was used to study rat cerebellum. After topical treatment with norepinephrine or stimulation of norepinephrine-containing afferents from locus coeruleus, there was a striking increase in the number of Purkinje cells with strong cyclic adenosine monophosphate reactivity. Other putative inhibitory transmitters had no significant effect on staining of Purkinje cells. The results provide the first histochemical support for the hypothesis that cyclic adenosine monophosphate can be generated postsynaptically in central neurons in response to noradrenergic stimuli. 相似文献
8.
Palmer LM Schulz JM Murphy SC Ledergerber D Murayama M Larkum ME 《Science (New York, N.Y.)》2012,335(6071):989-993
Interhemispheric inhibition is thought to mediate cortical rivalry between the two hemispheres through callosal input. The long-lasting form of this inhibition is believed to operate via γ-aminobutyric acid type B (GABA(B)) receptors, but the process is poorly understood at the cellular level. We found that the firing of layer 5 pyramidal neurons in rat somatosensory cortex due to contralateral sensory stimulation was inhibited for hundreds of milliseconds when paired with ipsilateral stimulation. The inhibition acted directly on apical dendrites via layer 1 interneurons but was silent in the absence of pyramidal cell firing, relying on metabotropic inhibition of active dendritic currents recruited during neuronal activity. The results not only reveal the microcircuitry underlying interhemispheric inhibition but also demonstrate the importance of active dendritic properties for cortical output. 相似文献
9.
Gamma-aminobutyric acid antagonism in visual cortex: different effects on simple, complex, and hypercomplex neurons 总被引：4，自引：0，他引：4
Intravenous bicuculline was used to examine how removing gamma-aminobutyric acid-mediated inhibition affects the visual response properties of single cortical neurons. Simple neurons were depressed and complex neurons showed increase in the vigor and range of responses. Hypercomplex cells were no longer inhibited by elongated stimuli. The results are consistent with present evidence concerning the origin and distribution of inhibitory connections within the cortex. 相似文献
10.
Repetitive presynaptic stimulation elicited slow membrane depolarization in neurons of inferior mesenteric ganglia from guinea pigs. This response was not blocked by cholinergic antagonists but was specifically and reversibly inhibited by a substance P analog, (D-Pro2, D-Phe7, D-Trp9)-substance P, which also depressed the depolarization induced by exogenously applied substance P. The atropine-sensitive slow excitatory and slow inhibitory postsynaptic potentials evoked in neurons of rabbit superior cervical ganglia were not affected by the substance P analog. These and previous results provide strong support for the hypothesis that substance P or a closely related peptide is the transmitter mediating the slow depolarization. The latter may represent a sensory input from the gastrointestinal tract to neurons of the prevertebral ganglia. 相似文献
11.
TYLER HR 《Science (New York, N.Y.)》1963,139(3557):847-848
Electrical stimulation of multiple peripheral nerves, elicited "H" reflexes in a patient, 61 years old, with botulism. These reflexes are extremely suggestive of some central release or failure of inhibitory control of a monosynaptic or polysynaptic spinal reflex arc. This "central" action of botulinus toxin is similar to that suggested for tetanus toxin. 相似文献
12.
Neuronal generation of the leech swimming movement 总被引：5，自引：0，他引：5
G S Stent W B Kristan W O Friesen C A Ort M Poon R L Calabrese 《Science (New York, N.Y.)》1978,200(4348):1348-1357
The swimming movement of the leech is produced by an ensemble of bilaterally symmetric, rhythmically active pairs of motor neurons present in each segmental ganglion of the ventral nerve cord. These motor neurons innervate the longitudinal muscles in dorsal or ventral sectors of the segmental body wall. Their duty cycles are phase-locked in a manner such that the dorsal and ventral body wall sectors of any given segment undergo an antiphasic contractile rhythm and that the contractile rhythms of different segments form a rostrocaudal phase progression. This activity rhythm is imposed on the motor neurons by a central swim oscillator, of which four bilaterally symmetric pairs of interneurons present in each segmental ganglion appear to constitute the major component. These interneurons are linked intra- and intersegmentally via inhibitory connections to form a segmentally iterated and inter-segmentally concatenated cyclic neuronal network. The network appears to owe its oscillatory activity pattern to the mechanism of recurrent cyclic inhibition. 相似文献
13.
电压门控钠离子通道对于脊椎动物脑神经起始、传播动作电位具有重要作用。为了解斑马鱼电压门控钠离子通道基因scn1Laa在脑神经中的作用,通过CRISPR/Cas9基因编辑技术,首次构建了可稳定遗传的生长没有受明显影响的scn1Laa缺陷型（scn1Laa-/-）斑马鱼家系。相比野生型,5 dpf（days post-fertilization,受精后5天）scn1Laa缺陷型斑马鱼兴奋抑制性神经元（氨基丁酸类神经元）表达相对增加,兴奋类神经元（谷氨酸能类神经元）和成熟神经元显著减少,脑部细胞增殖也显著减少。受精后5天和90 天的 scn1Laa缺陷型斑马鱼的运动较同时期野生型斑马鱼更为活跃,受精后90天的 scn1Laa缺陷型斑马鱼的运动具有明显的爆发性。以上结果表明,scn1laa缺失导致兴奋类神经元（谷氨酸能类神经元）以及神经细胞增殖减少,影响脑周围神经放电,导致运动神经调节障碍,出现运动行为异常活跃。即电压门控钠离子通道基因scn1Laa参与斑马鱼脑神经发育和生长,间接参与运动行为调节。同时本文也为进一步探究电压门控钠离子通道在脑神经中的作用奠定基础。 相似文献
14.
Lesch-Nyhan syndrome: evidence for abnormal adrenergic function 总被引：3，自引：0，他引：3
Subjects with the Lesch-Nyhan syndrome (hypoxanthine-guanine phosphoribosyltransferase deficiency with self-mutilation) exhibit an apparently unique pattern of adrenergic dysfunction characterized by elevated plasma dopamine beta-hydroxylase activity and an absence of pressor response to acute sympathetic stimulation. Patients with a partial deficiency of hypoxanthine-guanine phosphoribosyltransferase without self-mutilation do not exhibit these abnormalities of adrenergic function. 相似文献
15.
Tail shock produces transient presynaptic inhibition and longer lasting presynaptic facilitation of the siphon sensory neurons in Aplysia. The facilitation undergoes activity-dependent enhancement that is thought to contribute to classical conditioning of the gill- and siphon-withdrawal reflex. Inhibition of the sensory neurons has now also been shown to undergo activity-dependent enhancement when action potential activity in the sensory neurons is paired with inhibitory transmitter. This effect appears to involve an amplification of the same cellular mechanisms that are involved in normal presynaptic inhibition. These results suggest that activity-dependent enhancement may be a general type of associative cellular mechanism. 相似文献
16.
Electrical responses of insect central neurons: augmentation by nerve section or colchicine 总被引：3，自引：0，他引：3
Intracellular recording from the somata of central motor neurons in the cockroach Periplaneta americana normally shows little or no electrical response evoked by soma depolarization or by antidromic stimulation. Within 4 days after either cutting the axon or administration of colchicine, large action potentials can regularly be recorded from cell bodies of metathoracic motor neurons. Each experimental procedure evokes formation of a dense, perinuclear ribonucleic acid ring in the soma of neurons showing augmented electrical responses. 相似文献
17.
Electrical synapses are common between inhibitory neurons in the mammalian thalamus and neocortex. Synaptic modulation, which allows flexibility of communication between neurons, has been studied extensively at chemical synapses, but modulation of electrical synapses in the mammalian brain has barely been examined. We found that the activation of metabotropic glutamate receptors, via endogenous neurotransmitter or by agonist, causes long-term reduction of electrical synapse strength between the inhibitory neurons of the rat thalamic reticular nucleus. 相似文献
18.
Transneuronal transfer of herpes virus from peripheral nerves to cortex and brainstem 总被引：13，自引：0，他引：13
The transneuronal transfer of neurotropic viruses may represent an effective tool for tracing chains of connected neurons because replication of virus in the recipient neurons after transfer amplifies the "tracer signal." Herpes simplex virus type 1 was transferred transneuronally from forelimb and hindlimb nerves of rats to the cortical and brainstem neurons that project to the spinal enlargements to which the nerves receiving injections are connected. This transneuronal transfer of herpes simplex virus type 1 from peripheral nerves has the potential to be used to identify neurons in the brain that are related transsynaptically to different nerves and muscles. 相似文献
19.
Although acoustic communication is not pronounced in reptiles, analysis of single auditory neurons in the medulla oblongata shows that the cochlea is a frequency analyser. Auditory neurons of the lizard Coleonyx variegatus respond to acoustic stimuli over a range of less than 0.1 to 17 kilohertz and are maximally responsive between 0.8 and 2.0 kilohertz. The frequencies to which they are most sensitive differ from neuron to neuron, ranging from 0.11 to 4 kilohertz. Some neurons have an inhibitory area which greatly overlaps the response area, so that inhibitory areas do not seem to sharply tune the response area at this level of the auditory tract. The inhibitory area is responsible for producing in some neurons a phasic response and nonmonotonic relation between sound intensity and number of impulses. The response pattern shows a tendency to change from tonic to phasic in more advanced auditory centers. This may serve to code rapid changes in the acoustic stimuli. 相似文献
20.
CORRELL JW 《Science (New York, N.Y.)》1963,140(3565):387-388
Electrical stimulation of nerves to isolated rat and rabbit adipose tissue in vitro causes production of free fatty acids. Starvation increases the response. The response of white (epididymal) fat is prevented by sympathetic denervation. Direct evidence is provided showing that adipose tissue has the capacity to be an effector organ responsive to the nervous system. 相似文献